THROUGHOUT THE WORLD, CARVER HIGH FIDELITY AUDIO COMPONENTS ARE ACCLAIMED FOR TECHNOLOGY, RESPECTED FOR EXECUTION OF DESIGN, AND DEPENDED UPON FOR RELIABILITY. THEY ARE ALSO, AND PERHAPS THIS IS MOST IMPORTANT OF ALL, APPRECIATED FOR MUSICALITY.
POWERFUL—MUSICAL--ACCURATE
FOUR TECHNOLOGIES THAT HAVE CHANGED AUDIO FOREVER AND THE MAN WHO MADE THEM POSSIBLE.
Magnetic Field Amplifier Technology.
Early on, Bob Carver realized that virtually all available amplifiers were seriously underpowered. It took much more power to properly reproduce reality than could be produced using standard circuits. His first company, Phase Linear, became a leader in amplifier technology through the Seventies, producing the first really high-powered audio amplifiers. However, Bob was not satisfied.
"Why do powerful amplifiers have to be large, bulky, hot and expensive?", Bob asked himself.
The result is the Magnetic Field Power Amplifier which does the work of an eighty pound amplifier in a compact, cool-running nine-pound cube! Suddenly, sufficient power has become both affordable and manageable for the home stereo owner.
Read about it in detail on pages 4 and 5.
Sonic Holography Technology.
Bob Carver has always been an ardent fan of all types of live music. Like any discerning listener, he realized the limitations of conventional stereo for reproducing the reality of a musical performance. No matter how good the sound source was, how distortion-free the circuit path and how elaborate the loudspeakers, stereo was a pale copy of the concert hall.
"Why can't the sound field be expanded into three dimensions to fill a listening room--wider, higher and deeper than mere stereo?", he asked himself.
The result is Sonic Holography, a patented circuit which unlocks new dimensions of detail and spaciousness from any conventional stereo sound source.
Learn how it can redefine musical reality using your existing speakers, on pages 10 and 11.
Asymmetrical Charge-Coupled FM Detector Technology.
FM has always been the black sheep of the audio world. Unlike disc and magnetic sound sources, it is compromised by problems of transmission and reception that have often made it unacceptable as an audiophile medium.
"Why can't FM sound as good as other musical sources?", Bob wondered.
He knew that the method used to broadcast stereo FM was inherently deficient, having been designed for mono transmission and later "patched" to allow for stereo. Thus, conventional improvements in tuning circuitry were of little avail since they actually increased the reception of certain kinds of interference, distortion and noise.
Bob went to the heart of the problem and devised a revolutionary new approach which concentrated on "repairing" a part of the FM signal which is particularly prone to distortion.
The result is not only clean, clear signals from previously noisy stations but also the ability to receive weak stations which would normally have been buried in background noise.
Learn how it can improve your FM listening experience on pages 14 and 15.
Digital Time Lens Technology.
Compact Discs represent a significant improvement in frequency response and dynamic range, not to mention ease of use and permanence.
However, audiophiles' critical ears discerned differences between certain CD discs and their analog, phonograph equivalents.
"Why aren't some Compact Discs living up to their potential to reproduce music? Why is there a lack of ambience and shifting of tonality in some releases?", he dared ask.
After exhaustive electronic tests, Bob had several answers. He then set about inventing the Digital Time Lens circuitry which could return digital sound exactly as it was intended, with complete ambience and frequency balance.
Then and only then did Carver Corporation offer a Compact Disc player. Along with superb playback capabilities and a wide range of useful features, it gives the listener the option of applying Digital Time Lens technology to CD's which require it.
Learn more about this exclusive Carver feature on pages 22 and 23.
As you can see, Carver Corporation does not merely produce electronics to fill slots in its product line. Carver is committed to the design and manufacture of audio electronics which bring the listener as close as possible to the sound of the original musical performance.
Today, in a modern factory located north of Seattle, Washington, Carver is continuing to push the audio art to unprecedented heights and price/performance standards. On the coming pages, you will learn the details of how Carver electronics can make your listening experience more Powerful, Musical and Accurate.
--------- ------------------
MAGNETIC FIELD POWER AMPLIFIER TECHNOLOGY.
All our amplifiers and receivers utilize Bob Carver's proprietary technology, the Carver Magnetic Field Power Amplifier.
Its innovative design simultaneously solves three of the most basic problems found in conventional power amplifiers: high cost, great weight, and excessive heat generation.
The most basic audio problem has been and always will be how to turn electrical energy into physical waves of sound.
In other words, how to use the same electrical current that powers lights and vacuum cleaners to exactly amplify and emulate faint impulses and present them to your speakers.
Speakers need electricity to move air. They use it to generate magnetic fields inside the voice coils of their drivers. As the coils are repelled by fixed magnets within the speaker, they move outward, pushing the speaker cone with them. It, in turn, transfers that movement to the air in your listening room. A drum beat sounds on the record; energy flows to your speakers; the speakers push the air in some semblance of the original drum beat's impact.
The small speaker drivers which provide treble need only move a few thousandths of an inch and do not require much power. But larger drivers such as bass woofers must move considerable amounts of room air to achieve realistic impact. They travel back and forth hundreds of times per second, often against their own internal air resistance as well. That requires power.
The plain fact is, few amplifiers have the technical capabilities to provide enough power.
They can translate say, 90% of a musical waveform into the power your speakers need. But just can't deliver that Iast10%. If you look at graphs of this ever-present problem, you'll notice the top of the impulse has been clipped off. That's where the phrase "clipping" comes from.
musical waveform no-clipping clipping Even though most clipping happens as the amplifier is trying to complete a bass waveform, audible distortion is generated in the treble range. Called clipping distortion, these impulses are spikes of non-musical, high frequency power caused as the amplifier hits the bottom of its power reserves. At moderate levels, these spikes veil music with a thin film of distortion that occurs with every musical impulse.
At higher sound levels, they concentrate so much energy in the tweeter that it can burn out. It is important to remember this when considering amplifiers of higher power: Most speakers are destroyed by insufficient amplifier power-most often in the 20-50 watt range-not high power.
Before Bob Carver, the only way to get enough power to completely eliminate clipping distortion was to buy a traditional, brute-force power amplifier design. Often weighing over100 lbs., these designs store massive amounts of power against the instantaneous demands of music. They are very costly and inefficient because they produce a constant high-voltage level at all times-irrespective of the demands of the ever-changing audio signal. Even when there is no preamplifier signal to amplify, conventional designs are drawing half power from your electrical outlet and converting it to heat! Consider this analogy for how power supplies work. Imagine an enormous cast iron tub containing several hundred gallons of water. That's rather how conventional amplifiers store power: Huge capacitors and a gigantic power transformer soak up electricity and store it in advance.
When power is needed, it is transferred to the speakers (the bucket in our analogy) the circuitry "refills" the sink during a lull. This means there is actually LESS POWER during peak demands-and MORE wasted power during lulls.
Note that it takes an enormous "tub" to store enough water (amp power) to fulfill sudden demand. When this reserve is not being drawn on, the stored power is "evaporated" into heat.
Bob Carver set out to find a better way. A method of delivering the power speakers need without heat, bulk and distortion. The solution is elegant and effective.
Imagine a lightning-fast valve on the incoming water main line (the power outlet into which the Carver Amplifier is plugged). When water is needed, the valve senses the demand and opens, using the waterline's pressure to quickly deliver a large quantity of water.
Note that this approach provides ALL THE POWER NEEDED during peak demands... without keeping excess around during lulls. Also note that the WATER MAIN is doing the work of storing the excess, not a huge reservoir.
The "valve" we've described is our analogy for the Magnetic Field Coil inside each Carver amplifier. By delivering power only when needed, it can satisfy your speakers' need for power while generating less heat and virtually no distortion.
The patented Carver Magnetic Field Coil looks like a small transformer and yet it operates much differently than conventional transformers.
Because it can deliver extremely high peak to average ratios, it is perfect for musical signal applications.
The output of a Carver amplifier is, in reality, the output of the power supply being switched on and off at a rate directly related to the incoming audio frequency. The switching is done by a commutator which supplies an amplitude-modulated, step-like approximation of the audio signal to the output. This approximate waveform is then converted to a replica of the audio input by a small feedback linear amplifier. In effect, the small linear amplifier uses as its power supply rail the changing output of the commutator.
Since the instantaneous voltage output of the commutator is very close to the instantaneous output of the power amplifier, the voltage drop across the output devices is small and the overall efficiency is high. Instead of large heat sinks, Carver amplifiers' modest cooling requirements are provided by their chassis.
Theory of Operation of the Magnetic Field Coil
Referring to Figs. B1A, B1B and B1C, TR1 is fired and turns on at time t1. Current flows into MCI from time t1 to time t2. During this interval, current also flows in the secondary winding and charges C2 and C3 to voltage equal to V2 times the winding ration of MC1.
Since the output is clamped at + or-80 volts by D3 and D4, C2 and C3, the difference between the reflected clamp voltage (V2) is: V2 = 80 (n1 /n2). V1 must appear, because of conservation of energy, somewhere. Ordinarily, the voltage drop (V1 V2) would appear as IR losses in the primary. However, by winding a magnetic shunt into the Carver Magnetic Field Coil, a deliberate and controlled leakage Inductance L1 is formed. This cause V1 - V2 to appear across L1 in the form:
(V1-V2) =-L di/dt.
Fig. B1 Theory of operation of Magnetic Field Coil.
Fig. B6--Clipping detector circuit.
The energy associated with that quantity is stored in the field of Ll. The amount of energy thus stored is 1/2L1i2, where i is the current flowing at time t2. The amount of power that would otherwise be wasted is:
Power = energy/time = 1/2L1i2/t = 1/2L1i12/(t2-t1).
At time 12, the incoming 60-Hz line has fallen below the clamping voltage, hence D3 and D4 switch off. Once D3 and 04 are turned off, the tank circuit formed by L1 (the leakage inductance) and C1 (the commutating capacitor) begins to oscillate. However, since TRI commutates off as soon as its current passes through zero, only one half cycle of oscillation can take place. Once TR1 has commutated off, the field surrounding L1 begins to collapse. Since the flux linkages of L1 are common with n2, a flyback voltage appears on the secondary and causes D3 and D4 to switch on again, clamping the output to 80 volts. At time t4 current is no longer maintained by L1 since the stored energy has been transferred to the secondary of MC1 and to the load. The same sequence of events takes place during the negative half of the input voltage cycle.
Commutator Details. A more detailed examination of the power supply reveals that the secondary of the Magnetic Field Coil has multiple taps which drive three full wave bridge rectifiers to form six different levels of supply voltage: + or 25, + or 50, and + or 80 volts. A duty-cycle control circuit maintains these three voltage levels relatively constant, with some "softness" of regulation programmed into the system for good dynamic headroom of the amplifier. The output of these six voltage levels goes to the input of the commutator.
The commutator delivers an output voltage that is a step-like approximation of the audio envelope. The time-varying, conjugate-output voltages of the commutator go to a pair of complementary transistors to remove the steps, or to a small 15-watt amplifier whose B + and B supplies vary in level with the audio signal.
Fig. 65 Block diagram of Carver Magnetic Field Amplifier.
Protection circuits. As indicated in Fig. B5, Carver amplifiers employ an assortment of protective circuits, all designed to make the amplifier as fail-safe as possible.
The Carver Magnetic Field Amplifier Clipping
Detector senses the presence of high-frequency components that occur during clipping. The circuit, detailed in Fig. B6, has two inputs: The input audio signal and the output audio signal from the amplifier. So long as the output follows the input, the output of the differential amplifier, A2, will be zero. If the output fails to follow the input because of clipping or overload, A2 will have an output that is then differentiated by C1R1 and peak rectified by D1C2. This positive d.c. voltage is then time-integrated by D2C3. The voltage appearing at C3 represents the "stress history" imparted to the high-frequency driver during prolonged clipping. Too much clipping will cause the trip threshold to be exceeded, shutting off the supply.
Fig. B7 Voice-coil temperature integrating circuit.
A Voice-Coil Temperature Integrator circuit represents a first-approximation analog of a high-fidelity loudspeaker's thermal properties. The audio output of the amplifier is rectified and filtered by D1 and C1. Average voltage on C1 is related to the spectral energy distribution and to signal amplitude. C2 charges through R1. The voltage on C2 represents, to a first approximation, the thermal stress history of the loudspeaker system, taken as a whole. The integral Vi dT, the volt-amp time product, increases faster for high frequencies than for low frequencies. (Tweeters break down more easily than woofers, generally speaking.) The logarithmic junction of Q1 is used to get the product of v x i (power) delivered to the speaker.
Fig. B9 Shutdown circuit.
Fig. B8 Overcurrent trip circuit.
Two other trip circuits protect against overcurrent and out-of-phase low-frequency impulses. If too much current flows in the 0.1-ohm resistors in the output circuit, transistor Q1 in Fig. B8 turns on Q2 which trips the power supply. R1C1 serve as an integrating circuit (with an approximate time constant of 200 milliseconds) to prevent shut-down during very brief overloads.
Since the output of the left-channel amplifier is 180 degrees out of phase with the right channel (see Equipment Profile), in-phase signals at the input to the left and right channels will result in a small signal at Tpl. Out-of-phase signals, on the other hand, will produce a large signal at Tp1. Accordingly, the low frequency response at Tp1 is small for (L + R) signal components, and large for (L - R) signal components.
Response for high-frequency signals is virtually zero for both (L + R) and (L R) signals because of the bypassing effect of C1. A dropped tonearm, for example, will generate large (L R) signals, whereas musical bass tones generate primarily (L + R) in-phase signals.
Therefore, a low-frequency shutdown is arranged so that it will allow high-power, low-frequency musical signals to pass through, but will shut down for high power, low-frequency faults. The power supply will try to come on again but will turn off almost immediately (in about 20 milliseconds) after rising in voltage only slightly.
It should be clear from all of the above that the Carver Magnetic Field Amplifier is an extremely sophisticated piece of audio equipment that has left little to chance insofar as long-term reliability is concerned. L.F. Reprinted with permission from Audio Magazine
© CBS Inc. 1980
Carver amplifiers are not merely powerful.
They have been designed by a music lover with a critical ear for the nuances of natural sound.
Consider this comment by the editor of an audiophile magazine about one of the amplifiers you'll read about on the pages that follow: "...the equal of any power amplifier in transparency, focus and smoothness and, of course, are ahead of any other we tested in sheer gut shaking power and dynamic range. We especially enjoy hearing spatial detail, instrumental definition and completely natural dynamics on familiar records to a degree we did not know was extractable from the grooves when we listened through lesser amplifiers." A new recording and playback medium has made the power and accuracy of Carver amplifiers even more necessary for committed music lovers. If you haven't heard the fantastic dynamic range of the new Compact Digital Audio Discs, you're in for a wonderful surprise.
f you have, you'll agree that the sheer sonic impact of this recording medium makes underpowered amplifiers not only inadequate, but potentially fatal to even the best speakers.
You can increase your enjoyment of any kind of music by selecting one of four Carver Magnetic Field Power Amplifiers: The Carver M-200t (120 watts/channel), the Carver M-4001, 201 watts/channel), the Carver M-500t (250 watts/channel) and the Carver M-1.5t, which provides 600 watts per channel long-time-period reserve power into 8 ohms, and up to 750 watts per channel Dynamic Headroom.
Or, you may choose from one of three Carver Receivers ranging from 200 to 90 watts per channel.
Any of these choices will open up new worlds of listening enjoyment as your speakers ore finally given the freedom to fully reproduce he music you enjoy.
-- --- ---- ---
CARVER M-1.5t MAGNETIC FIELD POWER AMPLIFIER
Our M-1.5t description starts out with a story instead of the usual superlatives.
Once, Bob Carver visited a famous sound researcher who was attempting to recreate the "snip" of an ordinary pair of scissors. He used no less than TWENTY-FOUR 200-watt amplifiers for playback, yet when viewed on an oscilloscope it was apparent that the top of that instantaneous transient was being distorted. Believe it or not, he needed more power! It was evident that real-world sound occurs very quickly and requires far more power than ANY current amplifier could produce.
The M-1.5t is a culmination of Bob's search for Enough Power, the ultimate amplifier for the reproduction of music today and for years to come.
Why one thousand two hundred watts? Music is full of surprises such as explosive crescendos, combinant crests of demand created by multiple instrument sounds and the shock levels that some well-recorded instruments can instantly attain. This is what makes music live. These incredibly intense bursts of sound don't necessarily have to be loud. They are too short in duration. But, like the scissor snip, they are intense and demand power.
Recorded music sounds dull without these constantly-occurring, high-intensity peaks.
If your amplifier cannot provide the instantaneous power to surmount these rigorous musical punches when they are presented at its inputs, it makes a sound of its own devising, literally an electronic gagging we call clipping.
The result is an audible degradation which has pervaded your listening for years. A form of distortion which has been difficult to avoid S until the M-I.5t arrived.
How can the M-1. 5t weigh less than some preamps and yet pack more muscle than power amps weighing FIVE times as much?
The M-1.5t vs. convention. A traditional amplifier's power supply has only two chances during each AC line voltage cycle to recharge and store energy. To meet musical demands in between, it must maintain a reservoir of energy, which means that as conventional amplifiers grow more powerful, their transformers and supply capacitors must grow proportionately larger, too. The result is a vast increase in size, mass, heat and expense.
Light as a preamplifier, cool as a cucumber, the M-1.5t transforms almost all of the energy it draws into useable audio power with a patented power regulator. Engineered to be directly responsive to the moment-to-moment power requirements of your music, it is a direct "valve" from the power circuits of your house with no need for inefficient intermediate storage. Your speakers are literally getting their energy from the power generator! This is done with a patented Trac switch and Magnetic Field Coil which actually spend most of their time stepping UP the line voltage values and only deliver maximum line voltages at times of peak musical demand.
Rating the M-1.5t. The conservative 350 watt per channel rating on the back of the M-1.5t only hints at its true capabilities. When a musical note sounds, each channel of the M-1.5t immediately puts out up to 600 watts, diminishing over several seconds to the rated 3 50 watts.
Several seconds is a long time in the life of a music waveform. Any peaks requiring anything like 600 watts will come and go in a few HUNDREDTHS of one second. Let the waveform subside for as little as 1/100 of a second and the amplifier resets itself, capable of providing the 600 watts per channel again.
Because of the tremendous capacity of the M-I. St's power supply, there has been no need to isolate the channels. Thus, when pressed hard, either channel is free to BORROW an additional 150 watts from the other for a total of 750 watts.
Brute power controlled. Implicit in this much power is a set of carefully designed speaker and amplifier protection circuits.
Should you ever overload your amplifier, a unique clipping eliminator circuit pulls the M-l.5t out of clipping.
Next we designed a set of total shut-off mechanisms into the M-l.5t to protect against: 1) temperatures above 70°C, 2) excessive out of-phase infrasonic/low frequency signals, 3)
excessive DC currents. Your speakers are protected from ungrounded line-level connections, oscillation, and real-world accidents like shorted speaker wires.
The M-1.5t's final protection mechanism is very special. While good speakers have voice coil heat dissipation safeguards, the M-l.5t also keeps track, actually averaging loudspeaker input and "remembering" for about three minutes backward in time. If it judges the amount to exceed the safe limits for high quality loudspeaker woofer voice coils, it will momentarily interrupt power to cool them.
A window on power. Thirteen LED's on the M-1.5t's face simply monitor power. The fourteenth signals headroom exhausted.
(When it blinks at high levels, you know the special anti-clipping circuits are operating.) The fifteenth LED is a diagnostical fault indicator. Along with first two LED's, and an internally-generated tone, it informs you of overload problems, routine protection shut down and other occurrences.
The music of power. Of the Carver M-l. 5t, Peter Aczel, Editor and Publisher of The Audio Critic has said. " ... the equal of any power amplifier in transparency, focus and smoothness and, of course, far ahead of any other we tested in sheer gut-shaking power and dynamic range. We especially enjoy hearing spatial detail, instrumental definition and completely natural dynamics on familiar records to a degree we did not know was extractable from the grooves when we listened through lesser amplifiers. At this level of sonic performance, the astoundingly small size and cool operation of the M-1. 5t become the icing on the cake, rather than the main attraction."
Power for life. The Carver M-1.5t is all the amplifier your hi-fi system will ever need. If you like the final edge of reality in your playback, no matter what sound level you choose, the M-l. 5t is your answer. Are you ready?
Specifications: M-1.5t
Power: 350 W/channel into 8 ohms, 20Hz to 20kHz, with no more than 0.5% THD Power CO Clipping: 550 W/channel into 4 ohms; 430 W/ channel into 8 ohms 600 W/channel long term power into 8 ohms S/N: >100dB IHFA-weighted Freq. Bandwidth: +0,-3dB 1Hz to 100kHz I.M. Dist: 0.15% SMPTE Slew Factor: >200 Display: LED 1 msec attack 1 sec release Input Impedance: 100k ohms Protection: Short Circuit, Voice Coil temperature trip, Clipping, Thermal shutdown, DC offset Dimensions: 3 1/2"H, Weight 16 lbs.
--- --- ----
CARVER M-500t MAGNETIC FIELD POWER AMPLIFIER
Why you need more amplifier power. If you think two hundred and fifty watts a channel with peak reserves of up to 700 watts is overkill, read on. You'll change your mind. The reasons are logical and ultimately surprising.
Power is not loudness. Certainly to play music at high sound levels, speakers do require more power. But we're talking high fidelity, not sound reinforcement. Assume you don't intend to play your music any louder than you do now when you own a Carver M-500t... the improvement will still be audible.
LOW power kills speakers. NOT high power. A 40-watt receiver can actually burn out a speaker faster than the M-500t! Here's why.
To produce a bass note, a speaker can take up to 80% of an amp's power. If a woofer is to move faster or farther than your receiver can provide power for, the amplifier circuitry generates a high-frequency harmonic spike, a sort of electronic "cry of pain" which is routed directly to the tweeter either producing horrible distortion or eventual burn-out of the tweeter. Thus the tweeter (and your ears) are punished for the woofer's inability to get power from a weak amp.
Adequate power makes an audible difference. While the burned tweeter example is an extreme one, some audible clipping occurs virtually every time a low bass pulse sounds, even at moderate listening levels. The strike of a floor tom, beat of a tympani or snap of a Fender bass all can draw short peaks of over 500 watts per channel. When your modestly powered amplifier can't handle it, there are audible consequences.
Prove it to yourself by auditioning good speakers with the Carver M-500t and any 100 watt unit. It won't take a Golden Ear to hear the tight, crisp bass notes and the sudden absence of annoying high-end distortion you previously accepted as a normal part of music: The M-500t's power is freeing your entire signal chain from the tyranny of insufficient power! And if the new digital Compact Discs excite you, healthy power reserves are mandatory. Digital technology's tremendously expanded dynamic range taxes the best conventional amps and makes many more obsolete.
Why you'll want the Carver model M-500t Magnetic Field Power Amplifier.
If you're wisely sold on the electronic and sonic benefits of generous power resources, now we'll explain why you needn't invest in a massive "arc welder" power amp to satisfy those needs.
While the M-500t is a bit larger than our remarkable M-400t cube amp, it weighs just 22 pounds. Less than some preamps! No cooling fans vent its backside: no extruded fins protrude: the unit runs barely warm to the touch.
In contrast, conventional amps continually court meltdown by converting up to 60% of their energy into heat. The M-500t transforms fully 80% of its energy into useable audio energy. Thanks to a more advanced, more elegant and more practical approach to the design of power supply sections. Gone are the coffee can sized capacitors, massive power transformers and gigantic heatsinks found in old-style high-power amps costing thousands of dollars.
In their place is a patented, compact Magnetic Field coil which stores and controls energy, eliminating all need for heavy, costly parts required by the very best traditional designs.
Instead of two mono amps with dual transformers, capacitors, etc., each channel of the M-500t can actually BORROW unused power from the other channel during peak loads. Indeed, the M-500t can be operated as a 700-watt mono amp without any special switching! Conventional amplifiers are crude next to the M-500t's micro-computer monitor system.
Instead of controlling input stages, causing delays and distortion, the M-500t's computer acts as a FINAL gate, just before the speaker terminals, for instant overload protection. Thus sonic perfection stands no risk of being marred even while fully protecting your valuable loudspeakers against potential damage.
Dual, lighted, precision VU-ballistic meters provide a musically accurate picture of power output averaging yet react instantaneously to important transients.
We made sure the M-500t has a completely neutral signal path transparent in sonic character, resulting in zero listener fatigue. First compare the power, musicality and accuracy of the M-500t to any traditional amplifier made.
You'll be impressed by the superb, colorless sound of the cool, unruffled, light-heavyweight M-500t.
Specifications: M-500t
Power: 251 W/channel into 8 ohms. 20Hz to 20kHz, with no more than 0.15% THD Power @ Clipping: 350 W/channel into 4 ohms; 270 W/ channel into 8 ohms Bridged Power: 700W at 8 ohms S/N: >100 dB IHF A-weighted Freq. Bandwidth: +0,-3dB1Hzto100kHz I.M. Dist: .05% SMPTE Slew Factor: >176 Display: Peak responding meters, 5 meet attack, 1 sec decay Input Impedance: 15K ohms Protection: Short Circuit, Thermal shutdown, DC offset Dimensions: 3 1/2" H, 17 1/2" W, 12 1/2" D, Weight 23 lbs.
--- --- ---
CARVER M-400t MAGNETIC FIELD POWER AMPLIFIER
Why 201 watts per channel?
Does the remarkable Carver M-400t put out more power than you ever considered necessary for accurate music reproduction at normal listening levels? The surprising fact is, you need every watt of the power provided by this remarkable little ten-pound cube. Here's why.
Music is full of surprises such as quick transients, combinant crests of demand created by multiple music waveforms and the explosive levels that some well-recorded instruments can instantly attain. We hear all this in live music: indeed, this is what makes music live. But we don't hear these incredibly intense bursts of sound as being loud-they are too short in duration-just live! Nonetheless these lightning-fast, high intensity peaks MUST be reproduced to make recorded music feel real.
And that's up to the power amplifier. If the amplifier cannot provide the instantaneous power to surmount these rigorous musical peaks, it makes a sound of its own devising, literally an electronic squeal of anguish. It may be an inoffensive "click" at low levels, a sound you've come to accept as part of the music or it may be an annoying "snap" which we call clipping, an ominous sign the amplifier's reserves are being drained with each waveform.
That sound is proof of the audible degradation of your system sound when adequate power is lacking. Prove it exists, compare the M-400t and any lower-powered amplifier with the same signal chain and speakers. One sounds crisp and fresh. The other vaguely muddled, even at low volumes.
Manufacturers of underpowered electronics have helped foster several myths we'd like to address after you've convinced your ears that 201 watts/channel is musically refreshing.
MYTH 1. Power means loudness. The point of more power is to have much of it in reserve, not to blast the neighbors. We don't expect for you to play your music any louder than you did when you under-powered your system without an M-400t.
MYTH 2. High power kills speakers. Actually, LOW power destroys many more speakers. Yes, illogical as it may seem, the lowly 40-watt receiver can "kill" a speaker far faster than the M-400t! When an amplifier can't put out what a speaker demands, it sends a nasty spike of high frequency sound out to the speaker, which is routed to the easy-to-burn-out tweeter.
Which often does. The less power your system has, the more chance there is these clipping spikes will occur when you play music with lots of bass, compact discs, or turn up your volume to very loud levels.
MYTH 3. High power means heat and weight. The M-400t weighs less than most pre amps and yet packs more muscle than power amps weighing five times as much. How? After all, no cooling fans vent it, no extruded fins protrude and the unit runs barely warm to the touch!
The M-400t vs. convention. In a traditional amplifier, the power supply only has two chances during each AC line voltage cycle to recharge and store power. To meet musical demands in between it must maintain a reservoir of power.
This means that as conventional amplifiers grow more powerful, their transformers and supply capacitors must grow proportionately larger and court meltdown by converting up to 60% of their energy into heat.
The M-400t transforms fully 80% of its energy intake into useable audio energy with CARVER Z-1
--- --- ---
WIDE BAND Z COUPLER
While CARVER Magnetic Field Power Amplifiers are usually found in systems which are controlled by a preamplifier, a growing number of serious audiophiles with modest budgets utilize a Magnetic Field Power Amplifier (connected through a CARVER Z-1 Wide Band Z Coupler) with low-power receivers or integrated amplifiers.
a patented power supply engineered to be directly responsive to the moment-to-moment power requirements of your music.
This is no simple feat, however, and requires a special Triac commutator and Magnetic Field Coil which actually spend most of their time stepping UP line voltage values and are only called upon to handle maximum line voltages at times of maximum demand.
Sophisticated protection for your system. The M-400t dutifully responds to musical input and will transmit those demands to your speakers ... which will get quite a work-out. To prevent damage, the M-400t has an elaborate logic-controlled protection system, and to prevent clipping and over driving. The system simply shuts down output for several seconds before resumption, testing output demand before continuing. Should the problem be a short or other massive malfunction, no damage can occur.
Physically the M-400t is simplicity itself.
Only a matched set of power LED's accent its front. Volume is controlled by the input signal eliminating the need for gain controls.
The M-400's back utilities are spare and to-the-point: speaker terminals and input sockets.
The most important test. Hardware, buzzwords and specmanship aside. your final decision should be made by the sound of an amplifier. Compare the Carver M-400t to any 200-250 watt/channel conventional power amplifier around, Class A, B, H. G, Z. O or otherwise. The class that stands out will be the superb colorless sound of the cool, unruffled, light-heavyweight M-400t. Powerful. Musical. Accurate and, above all, affordable.
Specifications: M400t
Power: 201 W/channel into 8 ohms, 20Hz to 20kHz, with no more than 0.5% THD Power @ Clipping: 300 W/channel into 4 ohms; 250 W/channel into 8 ohms Bridged Power: 500W at 8 ohms SIN: >100dB IHF A-weighted Freq. Bandwidth: +0, 3dB 1Hz to 100kHz I.M. Dist: 0.05% SMPTE Slew Factor: >135 Display: LED Peak responding 1 msec. attack .5 sec decay Input Impedance: 30k ohms Protection: Short Circuit; Voice Coil temperature trip; Clipping; Thermal shutdown; DC offset Dimensions: 6 3/5" cube, Weight 9 lbs.
The CARVER Model Z-1 Wide Band Z Coupler is an impedance matching device which enables a receiver or integrated amplifier to be used with CARVER Magnetic Field Power Amplifiers.
Many low-powered receivers and integrated amplifiers have excellent phono stages and line amplifiers. However, their power amplifier sections, in addition to being underpowered, are frequently incapable of even mediocre performance with many loudspeaker loads.
The Z-1 presents an optimum noninductive load to the power amplifier in the low-power receiver or integrated amplifier. When coupled with the Z-1, the outputs of the receiver or integrated amp are used to drive the CARVER Magnetic Field Power Amplifier. The result is awesome sonic performance from a relatively inexpensive system.
Dimensions: 2 x 2 x 2 3/4"
-- -- ---- --
CARVER M-2 00 t MAGNETIC FIELD POWER AMPLIFIER.
The smallest Carver Magnetic Field Power Amplifier is more powerful than most company's largest amplifiers! Once you have heard the M-200t, you will wonder how you managed with less power.
Because any less power regularly submits your ears to audible distortion called clipping. At moderate levels, you may not think you notice it. But that's because underpowered TV's, car radios, portable sound sources and virtually all low powered hi-fi components have made us accustomed to the haze of minute distortions which occur thousands of times per minute.
The M-200t has the reserves of power necessary to allow your speakers to complete each musical waveform ... instead of snapping it off.
The resulting clarity can restore a surprising amount of impact and detail to your existing records-played over your existing speakers with no further modifications.
Yet it is with the emergence of digital recording and playback technology that the M-200t stops being a luxury and turns into an absolute necessity. When you first hear a CD, your ideas of "loudness" and "softness" are completely overturned. Digital holds surprises with every passage, ranging from utter silence to exploding power that taxes your whole hi-fi signal chain, causing clipping distortion that isn't subtle anymore. The kind of clipping which can actually damage speakers.
The simple answer is to add the M-200t with its remarkable amplifier and speaker protection circuitry. This Magnetic Field Amplifier has the ability to deliver the power needed for digital in a cool-running package a THIRD the size of traditional amplifier designs.
Its sophisticated amplifier and speaker
protection circuits monitor conditions that could damage your equipment, shutting the M-200t down before problems occur. Voice coil overheating, long-term clipping, catastrophic short circuit and even excessive DC voltages are problems which the M-200t is designed to automatically circumvent.
The result is the freedom to truly enjoy Compact Discs or any other music source at realistic listening levels. If you're interested in upgrading your system with a minimum outlay of money and maximum immediately audible sound improvement, visit your Carver dealer soon. You'll discover that even a "small" Carver amplifier can make a LARGE increase in your listening enjoyment.
Specifications: M-200t
Power: 120 W/channel into 8 ohms, 20Hz to 20kHz, with no more than 0.15% THD Power .@ Clipping: 200 W/channel into 4 ohms; 130 W/channel into 8 ohms Bridged Power: 350W at 8 ohms S/N: >100dB IHFA-weighted Freq. Bandwidth: + 0, 3db 1Hz to 100 kHz I.M. Dist: 0.15% SMPTE Slew Factor: >100 Display: Power/Protection LED Input Impedance: 100k ohms Protection: Short Circuit, Voice Coil temperature trip, Clipping, Thermal shutdown, DC offset Dimensions: 2.55"H, 17.32"W, 9.20"D, Weight 10.25 lbs.
-- -- --- --
CLOSER TO REALITY. THE MAGIC OF SONIC HOLOGRAPHY.
Why did stereo catch on back in the Fifties? Why aren't we perfectly content listening to mono? The answer is obvious, you say: Stereo is more lifelike.
True. Slightly more lifelike. The way a color photo is more "realistic" than a black and white photo. Yet, like these two-dimensional representations, stereo is a compromise when compared to reality. No matter how good your speakers are, no matter how good the sound source is, the results are only barely comparable to a live performance.
Conventional stereo sound is an illusion, and for some listeners not a particularly successful or convincing one. Stereo reproduction is subject to fundamental distortions of spatial perspective, sufficiently severe that no six-year-old with normal hearing will be fooled into confusing a stereo playback with a real, live sonic event.
Consider, by analogy, the illusion of depth perspective that is provided in drawings and paintings by converging straight lines and the hazy reduction of contrast in "distant" objects.
The geometry of perspective is part of the perceived real world, and rendering it is an essential requirement for any realistic painting. Still, few people viewing paintings have ever been fooled into believing they were looking through a window at a real three-dimensional scene. And while stereo sound is both more realistic and more pleasing than monophonic reproduction, it is still only an attractive illusion.
Rather, the imaging of stereo is an acquired taste which audiophiles learn to be sensitive to acclimating to its unnatural perspective in order to enjoy the portrait of sound which the stereo system paints upon the wall between the loudspeakers.
In reality, sound approaches you not just head on but from the sides and from behind. It reverberates through a room, giving you cues as to not only the position of the performers but your position as well. Incidentally, this sort of sonic information is not limited just to classical music recorded in a concert hall. Multi-track pop music also contains ambient and reverberant information. After all, a guitar amp, drum or saxophone are played and recorded in a three-dimensional space. It's just not very apparent listening to stereo.
Previous approaches to heightening the feeling of dimension concentrated on adding more sound sources, usually behind the listener.
On certain kinds of recordings, the resulting reverberant effects can be very pleasing. In fact, we incorporate this type of rear channel enhancement on our C-4000 Preamplifier.
Still, using this method exclusively assumes that what is coming from the front stereo speakers is the best possible version of sonic reality.
Bob Carver knew that more was possible with just two speakers and regular sound sources, The key is Sonic Holography.
Very briefly, the Sonic Hologram presents timing and phase information that now exists in your records, but has been inaudible with normal stereo components. With Sonic Holography, this information emerges in three-dimensional space around the listener. The precise location of instruments and voice can be pinpointed.
As one reviewer put it, "The effect strains credibility... the miracle is that it uses only the two normal front speakers." Why is Sonic Holography so much more lifelike and how does it achieve the effect with normal stereo records? First let's consider stereo. The problem is simple: Each ear hears both speakers.
To see why this is important, consider the process of recording and reproducing a sound--one musical note played by one instrument, located several feet to the left of the center of the stage. A live sound source produces one sound arrival at each ear.
What do you hear as a listener if you are located in an ideal front-and-center seat? The sound spreads out in all directions at a speed of approximately 1100 feet per second. If you are facing the center of the stage, the sound arrives at your left ear first and at your right ear very shortly afterward--how long afterward depends on its angle of arrival.
----p52
If the sound source is exactly in front of you, identical signals arrive at both ears at the same time. Since the instrument in our example is only a few feet left of stage center and so is only slightly to the left of front (rather than 90 degrees around to the left), the arrival of the sound at your right ear is delayed by a small fraction of a millisecond and since your head blocks high frequencies, but isn't large enough to be an effective barrier for lows, your right ear receives a sound that is slightly filtered by the acoustic shadow of your head.
Inside your brain is organic "circuitry" which analyzes these dual arrivals and reports just exactly where the source of the sound is.
Actually, its job is infinitely more complicated since it is also receiving lots of reflections from different directions. It sorts all of these out and gives you additional information as to where you are in relation to the sound source, as well as what size the room is and what its reverberant qualities are.
If the sound is recorded and later played back via loudspeakers, the result will depend on the microphone technique employed. Consider the simplest and most common method: The sound is recorded via a single close-up microphone whose signal is "pan-potted" i.e. split and recorded in both stereo channels but slightly stronger in the left channel in order to place its image slightly to the left of center. In playback the sound emerges simultaneously from both speakers (a little louder in the left). Assume that you are sitting equally distant from the speakers, facing the mid-point between them. The sound from the left speaker arrives at your left ear, and at the same time the sound from the right speaker arrives at your right ear.
There's a little difference in intensity and so your ear-brain "circuitry" pinpoints the sound a little to the left of center. Fine so far.
Unfortunately, there was one live instrument ... but there are two speakers. A fraction of a millisecond later the sound from the left speaker, after filtering by the acoustic shadow of your head, arrives at your right ear; and similarly the sound from the right speaker arrives at your left ear. Not so fine.
----p52b
Remember that in the "live" listening experience the single sonic event produced just two arrivals at the ear; the delay and frequency spectrum differences between the arrivals at the two ears are the primary cues which the brain uses to determine the direction of the sound source.
But now the sonic event has been muddled with a total of four arrivals at the ears. Your ear brain analysis center can't figure out where the other two sonic events are coming from. This is an undesirable side effect sometimes referred to as Interaural Crosstalk. It results in a smearing of the stereo effect because your hearing mechanism cannot properly perceive all the imaging and spatial information that is being sent out.
The goal of the Carver Sonic Hologram Generator is to eliminate the "extra" set of sonic arrivals that occur with conventional stereo playback, but which do not occur in real life.
---p52c
Special circuitry analyzes and generates a third set of impulses which are calculated to exactly cancel the second, muddying set. You don't hear this audio signal. It is, instead a sort of mirror image of the extra sonic arrivals, but out of phase so that one set "neutralizes" the other.
Thus restoring perception of differences in depth and ambience in the stereo image which are "masked" in ordinary stereo playback.
-- --- --- --
SONIC HOLOGRAPHY
Live performance: Note that in the concert hall setting the sound is heard with timing and amplitude cues. Three dimensional!
Conventional stereo: Note that when listening to conventional stereo the sound is heard, more or less, on a Flat curtain of sound between the two speakers. Volume differences only. The timing cues are gone.
Sonic Holography: With SONIC HOLOGRAPHY, the sound is reproduced much like that of a concert performance. complete with timing. phase and amplitude cues.
To summarize,
--A live sound event consists of: One set of sonic arrivals at the ear
--Stereo reproduction consists of A first set of sonic arrivals plus a second set that causes interaural distortion.
--Sonic Holography provides: A special set of cancellation signals that intercept and cancel the distortion-causing sound arrivals of the second set resulting in: Only one set of sonic arrivals at the ear. (Just as the live performance.)
The ear/brain system can now receive the unambiguous timing and phase information that exists when we listen to real sonic events with only two arrivals-one per ear. A great deal of the subtlety of a real performance, including a clear sense of the size or "sonic signature" of the performance environment can be recovered from the recording, which is all but lost In conventional stereo playback.
The aural sound stage expands beyond the speakers and often beyond the wall of your listening room as well. Instruments, vocalists and sound effects come into focus, each in their own, tangible position. It is if you have adjusted the focus of a telescope. What was blurred becomes sharp. What was narrow is turned into a dramatic panorama.
Can any other methods achieve exactly the same effect? No. Unlike reverberant systems or binaural add-on devices, the Carver Sonic Hologram Generator is not a signal processor per se.
It does not change the existing signal, but rather adds extra, invisible cancelling signals.
Why is this process called Sonic Holography?
An optical hologram is a photograph made with a laser whose coherent beam of light is split into two beams and used to illuminate an object; the two beams are recombined, forming alternate rings of constructive and destructive interference, and the interference pattern is photographed. When the picture is developed and another laser is used to project it, a three-dimensional image of the photographed object is projected in space.
By analogy, a sonic hologram generator takes the beam of sound produced by each loudspeaker and splits it so that a related beam of sound is produced by the opposite speaker in such a way that acoustic interference patterns of the sound occur in the air near each ear, revealing the true three-dimensional sound image that was hidden in the stereo recording.
Sonic Holography in action is spectacular.
You don't need a trained ear to notice the difference. Suddenly the listening field extends wider, higher and deeper than the speakers. You are literally immersed in the performance. But don't take our word for it. Begin by reading what major audio magazines had to say about Sonic Holography.
"When the lights were turned out we could almost have sworn we were in the presence of a real live orchestra." Hal Rodgers, Senior Editor, Popular Electronics "The effect strains credibility-had I not experienced it, I probably would not have believed it... the miracle is that it uses only the two normal front speakers". Julian Hirsch, Hirsch-Houck Labs, Stereo Review
... it brings the listener substantially closer to that elusive sonic illusion of being in the presence of a live performance." Larry Klein, Technical Director, Stereo Review "... seems to open a curtain and reveal a deployment of musical forces extending behind, between and beyond the speakers ...terrific." High Fidelity The next step is to visit your nearest Carver dealer and hear one of the four precision components which incorporate Bob Carver's patented Sonic Holography circuitry: The C-4000 and C-1 preamplifiers, The Carver Receiver 2000 and an add-on component, the C-9 Sonic Hologram Generator.
Each not only has the potential to bring your existing record collection alive but also to make Compact Discs all the more stunning. Experience Sonic Holography soon and hear what you've been missing all these years.
-- -- --- -- --
CARVER 4000t HIGH FIDELITY CONTROL CONSOLE
Under all those buttons and knobs is, first and foremost, one of the finest audio preamplifiers in the world. Although the 4000t can combine up to five separate functions to recreate the vivid reality of live sound, its primary role is that of a fine "straight-wire" preamplifier dedicated to perfectly amplifying real-world musical signals without a trace of distortion.
Its phono stage lets you match virtually any cartridge to the ultra-sensitive phono pre amp stage where infinitesimal impulses from your cartridge are translated into line level voltage. Not only does the 4000t allow capacitance matching between itself and the cartridge/cable load, it eliminates a main source of noise and distortion in the bargain.
As the signal passes through successive stages it retains fidelity to the point where one watt of real-world output results in just 0.000000251 watts of distortion. Zero normalized phase shift. Zero group delay. Noise performance within 1dB of the theoretical limit of real-world cartridges. No slew limiting. No overload.
A superb range of controls. There are separate tone controls for each channel, plus a choice of turnover frequencies and a defeat for instant comparison. A 12dB/octave infrasonic filter helps eliminate speaker cone flutter and distortion caused by warped records, acoustic feedback, and tonearm resonance, there is a discrete headphone amplifier, and a speaker mute switch which allows you to cut sound momentarily without changing the master volume control setting. A stereo-mono switch instantly checks for cartridge and speaker phasing errors. You can dub between two tape decks interchangeably. Additional external processors may be added at any time and switched from the front panel. And of course ALL sound processing circuitry is instantly defeatable for comparison and for the pursuit of eternal flatness, may it exist in all our hearts and longings.
Yet we think there is more to reality than flatness.
Consider the nature of music. Music arrives at our ears in-phase, alive with all nuances of the reverberant room, the crisp dynamics of instruments, the position, sound quality and even natural spectral frequency responses all vivaciously present. It was this challenge of reproducing reality which set Bob Carver to creating the complete 4000t.
The achievement of Sonic Holography.
Consider each sonic event of a musical performance. For example, when a drum strikes a note in front of you, each ear receives a sound arrival which tells it just where that drum is in space: one sound source; two sound arrivals.
A pair of speakers attempt to deceive your ear with two sound arrivals just like in real life. But then each ear gets another sound arrival from the opposite speaker. Two sound sources; four sound arrivals. Confusion.
Sonic Holography generates yet another set of signals which exactly cancel the spurious second set of sound arrivals. Your ear again hears true sound with two sound arrivals.
Sound suddenly bursts forth wider than your speakers. Higher (and lower) than your speakers. Closer and farther back-even to the sides of you. Instead of a tiny window, the image of sound is a giant panorama, freeing you from the room's dimensions.
Example: "Time" from Dark Side of the Moon by Pink Floyd. Each clock is individually discernible. Did you know that they were set up in rows? Example: Suite in F by Holst. You can discern the position of the first and second trumpet sections and even the three saxophones. The tuba's valve sounds are discernible below the sound emanating from his bell! Example: Your favorite music, no matter what your tastes.
Restoring the hall: Time Delay. Along with the sound field in front of us, we must consider the total listening environment including reflected sounds received from behind us.
These place us within the listening environment, giving depth and dimension, immersing us in sound.
The 4000t time delay system is designed to re-create this larger feeling of acoustic space with a special processing circuit. This requires just two inexpensive speakers and an auxiliary amplifier which may be unobtrusively placed behind the listener. Adjustments allow you to control the "size" of the environment you wish to simulate; a line level output is provided.
Correcting digital software: The Digital Time Lens. The Digital Time Lens adds the finishing touches of sonic accuracy and realism to Compact Discs. It turns an innovation into near perfection by correcting the ratio of L-R to L + R and restoring the octave-to octave balance of the original performance.
You will hear not only the greater dynamic range, quietness and richer bass you expect from compact disc technology, but also the musicality, spectral balance and spatial qualities of well executed high fidelity stereophonic reproduction.
Eliminating the noise: The Autocorrelator Noise Reduction System. Tape, record vinyl and even your electronics inevitably add hiss to music. Eliminating this final veil between you and reality is achieved by a special circuit which discriminates between random noise and musical information, stripping hiss-from 2kHz to 20khz. Non-random, low frequency noise such as hum and rumble are removed by a level-sensitive dynamic filter that operates below 200Hz. Music emerges from an almost silent background.
The Carver 4000t as an instrument.
With SONIC HOLOGRAPHY, Time Delay, Autocorrelator and Digital Time Lens features, the Carver 4000t opens up the opportunity for truly realistic sound reproduction. And you are in control.
Precision, gold band, laser trimmed resistors.
24K gold contacts on all mating surfaces insure perfect signal transfer.
G-10 glass/ epoxy circuit boards insure electrical stability year after year after year.
Precision machined (not stamped) metal parts.
Sealed, lubricated switches eliminate noisy switches over the lifetime of the instrument.
High clamping pressure, hot molded external connectors with dual wipers insure absolute electrical contact.
Specifications: 4000t
Distortion: THD 0.05%/IHF IM 0.003%/TIM 0.0% S/N: 98dB
Phono 1: 89dB re 5mV @ 47 ohms
Phono 2: 84dB re 5mV @ 47k ohms
Freq. Resp: + 0, 3dB, 1Hz to 60kHz
Equalization: +/- 6dB at 8kHz and 2kHz/ +/- 6dB at 40Hz and 150Hz
Noise Reduction: 10dB from 2kHz to 18kHz/10dB from 20Hz to 200Hz
Infrasonic Filter: 12dB/octave from 15Hz down
Time Delay: 26 msec front to rear placement
Dimensions: 6 3/4"H, 19"W, 8.5"D, Weight 11 lbs.
-- -- -- -- --
CARVER C-1 SONIC HOLOGRAPHY PREAMPLIFIER
The C-1 as one of the world's best preamplifiers. Forget for a moment the miracle of Sonic Holography.
Concentrate on one of the best preamplifiers on the market today. And one of the best pre-preamplifiers.
Accurately amplifying the infinitesimal output of a moving magnetic phono cartridge (with its varying impedance and capacitance), while matching the theoretical RIAA equalization curve built into every master disc, is the true determiner of a preamplifier's "sound." We start with two separate extended curve phono stages utilizing the quietest multiple emitter transistors in the world. The result is zero cartridge interaction. Zero normalized phase shift. Zero group delay. And noise performance within one dB of the theoretical limit of real-world cartridges.
No slew limiting. No overload.
Unmeasurably low TIM distortion. In fact, its output can drive virtually any load. No matter how resistive; no matter how capacitive.
Many esoteric preamplifiers would stop here, making a name for themselves just on the elaborate technology we have incorporated into the C-1's phono stage, pre-preamplifier.
Next, we paid such close attention to following stages by designing out group and phase delay that the C-1 can drive real-world loads with an input to output null in excess of 86dB. That means a watt of output signal tracks the input signal with such astonishing precision that just 0.0000002 51 of the output signal is imperfect, a level absurdly lower than the molecular level of your eardrum.
Included is a precision, infrasonic filter circuit to cut power robbing, destructive cone flutter caused by warped records, floor vibrations, direct drive turntable resonances and acoustic feedback from high listening levels.
They result in visible cone flopping, waste of amplifier power, and obvious distortion.
Next we added a set of variable turnover tone equalization controls, allowing general room and speaker adjustment. By providing a way of varying the mid-point of both bass and treble controls, you can change the "shade" as well as the intensity of tone control. If you prefer you can switch out the EQ control section at any time for instant sound comparison.
A good preamplifier should also be the total nerve center of your stereo component system. So we were careful to include five important switching features besides source selection.
Not only can you operate two tape decks through the C-1, you can dub from one to the other without reconnection.
A special external processor loop allows you to add outboard devices without engaging a tape monitor circuit. A stereo/mono switch lets you check speaker and signal source phasing.
Finally, instead of simply providing a powered headphone outlet which cuts out speakers when you plug in, we designed a speaker defeat switch which lets you select speakers, headphones or both.
Put quite simply, the specifications, features and performance of the C-1 preamplifier up to this point should place it in the $1000 to $3000 price range.
The C-1 is your gateway to Sonic Holography.
While the best you can claim from good stereo is that it "images between the speakers," Sonic Holography expands that postcard of sound into a magnificent cycloramic mural.
Wilder than your speakers. Higher than your speakers.
Extending around you, closer than, yet many feet deeper than your speakers. A true three-dimensional stage.
The difference between a porthole and picture window.
How does Sonic Holography work? Snap your finger a few feet from your right ear. That single "sonic event" resulted in two "sound arrivals." One to your right ear and one at your left ear. Now while ALL sound events in real life result in two sound arrivals, conventional stereo bombards the ear with FOUR sound arrivals: giving you a muddled and completely different set of cues than your ear-brain system has learned to process over a millennia of evolutionary adaptation.
Bob Carver's special circuitry analyzes these spurious signals and sends out another set which exactly cancel the second, confusing set. The result is your ears get just one pair of sound arrivals and think they're actually witnessing the sound event! High Fidelity magazine said it "seems to open a curtain and reveal a deployment of musical forces extending behind, between and beyond the speakers." Julian Hirsch of Hirsch-Houck Labs noted, ... the effect strains credibility." All with two ordinary stereo speakers and the C-1's Sonic Hologram section.
Quite frankly, while Sonic Holography works with virtually any speaker system, it requires precise attention to initial speaker placement. This initial set-up is made easier by detailed, lucid instructions and rewards the listener with a quantum leap in sound reality, whether you fancy Lizst or Def Leppard.
No matter what your listening tastes, the C-1 represents the ultimate combination of sheer musicality and superb value in one fine electronic instrument.
Specifications: C-1
Distortion: <.04% IM (CCIR or SMPTE); <.04% THD S/N: 96dB, IHF A-weighted, below 2V RMS
a. Phono: M.M. 82dB IHF A-weighted below 5mV HMS
b. Phono: M.C. 86dB IHF A-weighted
Freq. Resp: 5Hz 200kHz, +1 3dB
Equalization: ± 6dB @40Hz and 8kHz/ ± 6dB at 150Hz and 2kHz
Infrasonic Filter: 18dB/octave below 20Hz, f3 = 15Hz
Dimensions: 3.5"H, 19"W, 10"D, Weight 8 lbs.
-- -- -- - -
CARVER C-2 STEREO PREAMPLIFIER
The C-2 preamplifier joins a tradition of excellence. Imagine a sound system in your home utilizing your favorite turntable with either a moving coil or moving magnet phono cartridge being taped by your cassette deck and reel to reel.
Now imagine taping from one tape deck to another with the ease of just one click. Then, when you wish to move on to new dimensions, switch to either your digital disc player, your tuner or an extra signal processor at will.
All this flexibility is offered by the C-2 with one overriding prime directive: To reproduce your music with absolute sonic purity. This is made possible with the use of the finest quality electronic components, mounted on the highest quality, glass-epoxy circuit boards. The end result is the virtual absence of distortion.
The CARVER C-2 preamplifier offers the discriminating audiophile with a relatively moderate budget the opportunity for uncompromised sound and handsome design.
Let's take a "guided" tour of the C-2's front panel and explore the advanced features this remarkable preamplifier can bring to your system.
The Selector switch controls the various signal sources which you may have in your system: turntables with moving magnet and/or moving coil phono cartridges, FM tuner and an auxiliary input that's perfect for the new generation of Compact Digital Disc players, laser video disc soundtracks or VCRs. You can even hook up the audio output of many computers such as the Commodore 64, Apple or PC sound cards.
The Selector switch also controls which signal is sent to your cassette and/or reel-to-reel decks. In conjunction with the next switch this allows not only taping any input source but transferring the signal (dubbing) between two tape recorders.
The tape Monitor switch is normally left off unless you want to listen to a tape or check out how well it's being recorded. When you wish to play a cassette or open reel tape, simply click the selector from Off to Tape source I or 2. Ergonomically, this is a far easier approach to signal selection than the traditional "Tape Monitor" and "Dubbing" buttons often stuck off to the side of the regular controls.
A special Mode switch allows listening in mono, stereo, reversed-phase stereo, left-only and right-only modes. This allows enjoyment of classic monophonic transcriptions and provides a quick way of checking speaker phasing and turntable/cartridge performance.
In between these two signal selection buttons is a Headphone plug which allows you to enjoy the new breed of high-performance individual listening devices. Unlike some preamplifiers, this is not an underpowered afterthought. The C-2 lets you add headphone extensions of up to fifty feet and even pair up two sets of headphones without loss of volume or degradation of sound quality.
The C-2's Bass and Treble Tone Knobs control equalization circuits which allow carefully-planned increases and decreases in the overall sound spectrum. They are designed to boost and cut at the outer edges of the bass and treble frequency range without major effect to the midrange areas.
After the self-explanatory Balance control are four switches controlling various important functions. If you are not in need of equalization, a corresponding switch is provided which totally disengages the circuitry for "flat" response.
An External Processor Loop switch lets you add and enjoy equalizers, expanders, special speaker EQ boxes, open-ended noise reduction units or our own C-9 Sonic Hologram Generator.
The Mute control lets you cut off sound output without changing the volume control during record changes, telephone calls or while listening to headphones only.
Additional specialized circuits are accessed from the back of the C-2 as well. An Infrasonic Filter circuit helps protect your speakers from power-robbing, ultra-low bass distortions caused by turntable resonance, warped records, acoustic feedback and other "real world" problems.
Next to the phone inputs are a second set of sockets which allow precise control of Phono Cartridge Loading Impedances. By adding or subtracting resistance values with special plugs, your cartridge and connecting cable can be balanced to sound their best without peakiness or hollowness caused by improper loading impedance.
Two Line Gain Sockets allow a high-level gain choice of 15 or 2 5 dB to ensure the best possible match with your power amplifier's input needs.
The preamplifier measures 17.3 inches wide, 9 inches deep, 2.5 5 inches high. Weight approximately 6.5 pounds.
Technical excellence aside, the true measure of the C-2 is its overall sonic accuracy: rich, musical, and totally uncompromised sound delivered in a truly affordable package.
Explore the promise and performance of the C-2 at your Carver dealer today.
Specifications: C-2
Distortion: THD .05%; .05% IM (SMPTE); .05% IM (CCIR) 96db, IHF A-weighted re 2V:
a. Phono: M.M. 83dB IHF A-weighted re 5mV @ 47k ohm
b. Phone: M.C. 77dB IHF A-weighted re 500 uV @ 47k ohm
Freq. Resp.: 3dB @ 3Hz and 80kHz Equalization: ± 7dB @ 100Hz/ ± 7dB @10kHz
Infrasonic Filter: 18dB/Octave below 20Hz, f3 15Hz
Input Impedance: 100k ohm parallel with 150 pf
Output Impedance: 600 ohm
Dimensions: 2.55"H, 17.3"W, 9"D, Weight 6.5 lbs.
Gain Increase: +10dB boost, rear access
-- -- -- - -
CARVER C-9 SONIC HOLOGRAM GENERATOR.
Now any hi-fi system, from the smallest receiver to the largest separate stack, can be used to expand your listening horizons with the magic of Sonic Holography.
We've extracted the complex Sonic Hologram circuitry found in our C-6000 and C-1 audiophile pre-amplifiers and placed it in a compact outboard unit.
It connects in minutes to any receiver, preamplifier or integrated amplifier which has a tape monitor loop or external processor circuit.
True realism with Sonic Holography.
The illusion of stereo imaging is an acquired taste which audiophiles learn to be sensitive to-acclimating to its unnatural perspective in order to enjoy the portrait of sound which the stereo system paints upon the wall between the loudspeakers.
In reality, sound approaches you not just head on but from the sides and from behind. It reverberates through a room, giving you cues as to not only the position of the performers but your position as well. Incidentally, this sort of sonic information is not limited just to classical music recorded in a concert hall. Multi-track pop music also contains ambient reverberant information. After all, a guitar amp, drum or saxophone are played and recorded in a three-dimensional space. It's just not very apparent listening to stereo.
Sonic Holography presents timing and phase information that now exists in your records, but has been inaudible with normal stereo components. With Sonic Holography, this information emerges in three-dimensional space around the listener. The precise location of instruments and voice can be pinpointed.
You don't need a trained ear to notice the difference. Suddenly the listening field extends wider, higher and deeper than the speakers.
You are literally immersed in the performance.
Specifications C-9:
Rated Output: 2Vms
Maximum Output: 6Vms
Total Harmonic Distortion: less than 0.05% (20Hz to 20kHz)
IM Distortion: less than 0.05% (SMPTE)
TIM Distortion: less than .001% Noise: less than 100µV, IHF A-weighted
Image Resolution: 5° horizontal, 20° vertical (in THEORETICAL mode)
Dimensions: 1 3/4" x 3 7/8" x 17”; Weight 3.5 lbs.
CARVER MCt -- MIRROR-IMAGE GEOMETRY MOVING COIL TRANSFORMER
The Carver MC-t performs as well as esoteric transformers costing hundreds of dollars, making the potential of moving coil cartridges affordable for all music lovers.
Moving coil cartridges give the ear a feeling of fine-grained delicacy, of sheerness, transparency and effortlessness not found with even the best moving magnet cartridges. They have been likened to the differences between a fine silk scarf and a heavy woolen muffler, or a crisp champagne vs. a heavy-bodied vintage port.
Unlike bulky moving magnet cartridges, moving coil cartridges put the heavy magnets around a lightweight coil at the end of the cantilever, resulting in quicker response to the movement of the stylus. Unfortunately, far less energy is generated by waving a coil around in a magnetic field than by waving the magnets around a coil of wire. Some sort of pre-preamplifier is needed to get their output up to line level.
Some preamplifiers include electronic circuitry to perform the step-up to higher voltages. Unfortunately, even the finest active circuit cannot match a passive transformer for sheer quiet and ultimate signal to noise ratio.
Because they are simply two interwoven coils of wire without any power source or other components, they are as noise-free as the metal they're composed of. A signal enters the smaller of the coils and creates a magnetic flux which is picked up by a larger coil and hence "amplified" to line voltage.
Until Bob Carver approached the problem, moving coil transformers cost as much as $500. Handmade and often composed of exotic metals, they provided performance for a price too dear for many consumers. Less expensive transformers often exhibited ringing, phase shift and low frequency distortion.
Here, as with many other "esoteric" areas of audio, Carver has combined quality and affordability in a single product.
Dual, mirror-image transformers share a shielded space. The heart(s) of the MC-t are two totally separate transformers. One for the right channel and one for the left, sharing a specially designed geometric space which eliminates interaction. Each of the four coils is wound with the finest, low-oxygen wire in a proprietary configuration. Distortion and ringing are non-existent. Signals which enter and exit the MC-t differ only in their strength, not in their quality.
But we didn't stop with the coil configuration. A critical concern is shielding, since any sensitive coil of wire acts as a sophisticated antenna, collecting external signals ranging from radio transmissions and hair dryers to the very patch cords and speaker wire in your system! To combat this interference, the MC-t is housed in a seamless, mu-metal case, which in turn is shielded by grain oriented silicon steel, based on designs used in high-performance defense and space guidance systems. The internal transformers operate in total isolation from the electronically-noisy outside world.
The MCt can be switched to perfectly match the desired impedance of any fine moving coil cartridge.
Massed instruments and voices resolve into individual yet interwoven points of sound.
The intricacies of harmonics, overtones and ambiance spring sharply into focus. Harshness melts into musical piquancy. Storm clouds of muddy bass emerge as lofty peaks of tight, well-defined fundamentals. The very bouquet of a recording rises to fill your listening room.
Audition the remarkable MC-t at your Carver dealer soon and learn what moving coil technology can do for the sound of your favorite music.
Specifications:
Dimensions: 6" wide. 2" high. 3" deep.
Weight: 1 Ib. 11 oz.
Gain: 24 dB. Signal-to-noise ratio: greater than 100 dB IHF A-weighted.
Impedance: 3.9 ohms, 39 ohms, 110 ohms.
Frequency response: 3dB at 3Hz and 80 kHz
---- --------------
THE ASYMMETRICAL CHARGE-COUPLED FM STEREO DETECTOR: CLEARING THE AIR.
The Asymmetrical Charge-Coupled FM Stereo Detector
Bob Carver's third major audio innovation has a very long name and a very simple purpose.
To make FM sound as good as other stereo sound sources. Free of background hiss and annoying interference.
Unlike Sonic Holography and Magnetic Field Amplifier technology which solve problems that some of us have been unaware of, Bob Carver's third significant breakthrough solves problems you may hear every time you tune in an FM station. Non-musical sounds you've heard a thousand times. Annoying distortion that may have weighed against even spending the money for an FM tuner due to poor broadcast/reception sound quality.
FM was originally designed to broadcast rich, full-frequency mono. Frequency modulation transmitters were intended to broadcast better sound by varying frequency over a narrow, assigned band instead of changing the intensity of the signal (amplitude) the way AM did. A "carrier" frequency is modulated by music from 30Hz tol5kHz. And by other sources above that.
(see sidebar) Back in the Fifties, the result was less noise, deeper lows and crisper highs. Voila! High fidelity broadcasting.
This system worked just fine-and still does if you have a mono FM receiver. However, stereo arrived in the Fifties and engineers set about finding some way to send TWO signals. They toyed with putting the left channel on FM and the right channel on AM, splitting left and right channels into two smaller bands within the assigned FM band and a number of other "discrete" approaches.
None of which impressed the FCC. "Whatever you come up with," they ruled, "has to be able to deliver the whole signal to all those folks with mono FM receivers. We're not going to allow instant obsolescence just because some audiophiles want this new-fangled stereo." (This is the same reasoning that insured owners of black and white TV sets could still receive color transmissions.) The approach that was finally adopted is clever to say the least. It divides each FM band into blocks. The first is composed of left-channel-plus-right-channel (L + R). This is just a combination of both channels, much the way you'd hear through an FM clock radio that only has one speaker. it's mono, just like back in the Fifties.
The second band is left-minus-right (L R), that is, all those things which differ between left and right. This second signal is assigned its own "carrier" frequency above the range of human audibility. Special summing and subtracting circuits eventually sort the signals out at your FM tuner.
A brilliant solution ... if you live within sight of the transmitter. Unfortunately, this important second signal (L-R) is extremely prone to mishaps between the transmitting tower and your FM tuner. These are usually induced by multipath reflections off hills, buildings and the ground, causing more than one L-R signal to arrive at your tuner to confuse things.
The effect is much like that of TV picture ghosting which increases with the number of skyscrapers and tall hills between you and the tower. In both cases, the main signal deviates in frequency, "beating" with the reflected signals (phase modulation), causing destructive interference patterns which bear no resemblance to the original signal. Even the most expensive FM tuners are tricked into reading this phase modulation as frequency modulation. In fact, the better the tuning circuit, the more easily it is deceived!
Audio Ghosting. To get stereo FM perfectly, you'd have to be the only house in the middle of a vast flat plain with no other buildings anywhere on the plain.
Because any protruding mass-hills, mountains, skyscrapers, other antennas, even bridges-looms up to reflect signals while on their way to your tuner.
Then you get TWO signals. One directly, and one or more a fraction of a second later, after it's taken a longer angular path of bouncing off something. (This happens with TV and AM, too.
AM isn't audibly affected, but you can see the frustrating result on TV: a second, third and fourth image.) These additional images are disastrous to FM reception because they reinforce and then remove part of the signal alternately. As the main signal deviates in frequency, it beats with the reflective signal, causing constructive and destructive interference patterns which bear no resemblance to the original signal. An engineer calls these "beats" phase modulation.
While stereo FM receivers have made much of cancelling one component of this interference, they have never addressed the truly audible distortion caused by phase modulation.
Without waxing too technical, suffice to say that your FM receiver is tricked into reading phase modulation as frequency modulation, which is decoded and made into a brand new signal. The better your current tuner, the more faithfully it's deceived!
--------Multipath is caused by multiple reflections of the LR signal Charge-coupling circuitry cancels all but the true LR signal
----------Thus instead of just degrading the existing signal, multipath reception problems actually
CAUSE NEW AUDIBLE SOUNDS. And we've all heard how bad these sounds sound.
How, then, can the Carver ACCD circuitry improve this theoretically unsolvable problem? The first portion of the design can be thought of as the "Search and Destroy" section. It takes advantage of the fact that almost all noise and distortion is in the L-R signal portion. And, for every instantaneous noise or distortion voltage on one channel, there is a replica in the opposite channel.
The Carver Charge-Coupled circuit detects these dirty, mirror images and cancels them before they can reach your ears. They are in effect, "played off against each other" before being compared and combined with the L + R signal and decoded into stereo.
The results are a dramatic reduction in hiss, clicks, pops, picket-fencing and the myriad indescribable, unpredictable noises which often disturb FM listening. But just cancelling out parts of a signal is not enough. If Carver ACCD circuitry merely eliminated objectionable portions of L R, it could potentially suppress so much that no signal would exist at all. It would have thrown the baby (the stereo characteristics) out with the dirty bathwater (the noise and multipath). Luckily, 85% of the L-R signal duplicates the L + R signal, so quite a bit can be cancelled without losing imaging and ambience. The other 15% is totally different and represents the instantaneous phase relationships which produce stereo listening experiences. Rather than compromise and leave 15% of the signal at the mercy of topography, architecture and distant transmitters, Bob invented another circuit which could "treat" this last critical15% of the L-R signal while maintaining its sonic integrity.
It's called the Leading Edge Detector.
Bob Carver performed extensive psycho acoustic research to bring us Sonic Holography.
During these experiments, he discovered that, if properly matrixed, only 1/3 of the remaining nonredundantl5% of the L-R signal is required to convince our senses of a fully separated stereo experience. That may sound complicated, but it just means that out of 100% of the fragile L-R signal, onlyl5% of it is different that the sturdy L + R signal. And out of that, only 5% is really telling our ear-brain center anything important about imaging, spacial relationships or ambiance.
The Leading Edge Detector circuit operates only on this final 5% of the L-R signal necessary for our ears and brain to construct true stereo localization. By processing this narrow segment and then carefully interleaving it into the FM tuner's receiver matrix, a net noise and distortion reduction of 93.5% (over 20dB) is achieved.
But for the vast majority of American FM listeners, multipath distortion from building, hills and even just plain flat ground are the cause of most listening woes. For them, ACCD circuitry can deliver a stereo signal as noise-free as mono.
When first introduced in our TX-11 tuner, reviewers substantiated Bob's theory with down-to-earth raves over the improvement in sound quality. For example, "Distinguished (by) its ability to pull clean, noise-free sound out of weak or multipath-ridden signals that would have you lunging for the mono switch on any other tuner we know of." High Fidelity "Breakthrough in FM tuner performance. A tuner which long-suffering fringe area residents and those plagued by multipath distortion have probably been praying for.
"The significance of its design can only be fully appreciated by setting up the unit, tuning the weakest, most unacceptable stereo signals you can find, then pushing those two magic buttons.
Separation was still there; only the background noise had been diminished, and with it, much of the sibilance and hissy edginess so characteristic of multipath interference." Audio "... if you are way out in the suburbs or in a 'deep fringe' area, the Carver TX-11 tuner may well make a difference between marginal reception of the station signals you've been yearning to hear and truly noise-free reception of those same signals, permitting you to enjoy the music and forget about noise and distortion." Ovation "The Carver TX-11 is one of the few important circuit developments in FM radio to come ". along in the past several years. Audio "Its noise reduction for stereo signals ranges from appreciable to tremendous. It makes the majority of stereo signals sound virtually as quiet as mono signals, yet it does not dilute the stereo effect." Julian Hirsch, Stereo Review Now there are five ways to hear what they heard. Our Asymmetrical Charge-Coupled FM Detector circuit is available in the TX-2 Tuner, Carver Receiver, Receiver 2000 and Receiver 900 as well as the breakthrough TX-11 Tuner.
Visit your Carver dealer soon and tune into the only significant improvement in FM since the Fifties.
Tuning in on FM. How it works.
The FCC assigns FM channels ever 200 kHz across the FM dial at odd decimals, like 101.7 and 98.3. Each of these bands contains a number of different signal components.
-----p59 FM Signal
One we don't have to be concerned with is a special subcarrier at 67kHz called the Subsidiary Communications Authorization (SCA) signal. It is leased by FM stations to background music companies. Special receivers decode it and fill your local elevator, department store or grocery market with audible anesthetic. More recently, the band has been used to transmit coded financial information, news and other text, as well as for special programming for the visually impaired and foreign language translations.
At the opposite end of the frequency modulation spectrum is the mono L + R signal. This is the cornerstone of FM: the summed signal. You need to receive nothing else to get a nice, wide-frequency mono sound.
But in order to receive stereo, a lot more has to happen. A difference signal also has to be generated. This L-R signal is encoded into a subcarrier at 38kHz, two and a half octaves above the upper range of human hearing. In the encoding process, this subcarrier is cancelled out leaving two sidebands. Each is 15kHz wide and also well above the range of human hearing.
Now, you'll also note a "pilot" signal at 19kHz.
What's THAT for? If the two L-R sidebands are broadcasted with the 38kHz subcarrier, audible interference is caused. Yet it has to be there in some form. So the encoder first makes a "copy" of it at half the frequency (19kHz) and then eliminates it from the signal. At the receiver, the 19kHz signal is doubled back to 38kHz and used to decode the L-R signal. Note that this whole nifty plan goes awry when we get to the 19kHz pilot signal which IS audible without special signal processing.
At the receiver the signal is added and subtracted to produce two different channels.
A good way to think of this whole L - R/ L + R process is to consider a stereo transmission with a guitar on one channel and a singer on the other.
When the signals are added together, you get L + R, both singer and guitar together.
---Now one signal is combined with a "negative" version of the other signal, resulting in L R, or those components found in one channel but not the other.
---Your FM receiver gets both of these signals, one at 30 Hz to 15kHz and the other in the two sidebands up at 23-38kHz and 38-53kHz. After decoding them, they are processed two different ways.
L + R and L-R are subtracted from each other to get just the channel with the guitar.
----And the signals are combined which cancels out the guitar, leaving just the channel with the vocalist.
Mathematically, it's represented as:
(L+R) + (L - R) = L+R+L-R = 2xL (L+R)-(L-R) = L+R-L+R = 2XR
Of course the L and R sources are much more complicated than that since single instruments aren't on single channels. But in general you can begin to understand just how "jury-rigged" the whole FM broadcasting process is, just how complicated the decoding process within an FM receiver is ... and just how remarkable it is that we can get stereo at all, much less at anything approaching hi-fi quality.
-- -- -- - - - -
CARVER TX-II
STEREO FM TUNER WITH ASYMMETRICAL CHARGE-COUPLED FM STEREO DETECTOR.
Finally, an FM stereo tuner which can drastically reduce multipath and distant station noise and still provide fully separated stereo reception with space depth and ambience.
A rich, textured sound as it was intended thirty years ago.
Thirty years? Yes. Back then, FM was a noise-free, wide band alternative to thin, static-filled AM. But it was monophonic and by the Fifties stereo was the new recording standard.
Unfortunately, the transmission system selected to turn mono FM into stereo ended up degrading the ratio of signal to noise FIFTEEN TIMES! (More than 23 dB) That's the system we live with today: hiss and distortion filled unless you're in direct line with a strong station.
Understanding FM. Stereo FM is not like a 2-track cassette with separate signals next to each other.
Rather, there is a Left-Minus-Right and a Left Plus-Right signal. (A receiving circuit adds and subtracts the sums and differences to get Left only and Right-only Signals.) Left + Right comes in just fine because it's mono. It's that Left Right signal (stereo information) that's to blame because it's extremely prone to "mishaps" on the way to your home.
Audio Ghosting. To get stereo FM perfectly, you'd have to be in the only house in the middle of a vast flat plain with no other buildings anywhere. Any protruding mass-(hills, skyscrapers, other antennas)-looms up to reflect signals while on their way to your tuner, resulting in two signals.
One directly, and one a fraction of a second later, after it's bounced off something.
The result is not only scratchy reception but rhythmic pulsing of the sound (called "beating") and whole new noises caused as conventional receiver circuitry wrestles with the interference.
Not even the most expensive traditional tuner circuitry can conquer these problems because none of them approach the problem the way Bob Carver's TX-11 does.
Charge-Coupling , the "Find and Cancel" circuit. Almost all noise and distortion is exactly 180 degrees out of phase with itself. For every instantaneous noise or distortion voltage, there is a replica in the opposite channel.
Simply put, the TX-I l's Charge-Coupled circuit detects these tell-tale, dirty mirror images and cancels them before they reach your ears.
If that sounds like we're eliminating the L R channel entirely, we're not.
While 85% of the information carried in the "dirty" L R channel is duplicated by "clean" L + R signal (and can be edited out by our Charge Coupling circuit), 15% is the critical phase relationship information which produces ambient stereo.
Stopping at 85% would give us stereo plus 15% distortion; knocking off 100% would be mono. Here's how we achieved mono quality with stereo ambiance.
The Leading Edge Detector. While studying the relationship of ear and brain during development of Sonic Holography, Bob Carver discovered that only one third of non redundant L R information (I/3 of 15%, or just 5%) is required to convince our senses of a fully separated stereo experience. But only if that 5% is properly electronically processed.
The Carver Leading Edge Detector operates on just that part of the L R signal required for our ears and brain to construct true stereo localization. By blending that 5% back into the TX-11's signal matrix, a net reduction of 93.5% or in excess of 20dB of noise reduction is achieved! All of the ambient and localizing information is recovered.
Without the hiss.
Without the distortion.
Sixteen presets for a reason. The reason you'll appreciate no less than sixteen different instant FM listening choices.
You'll suddenly pull in stations in surprisingly distant cities and suburbs. Underpowered local FM stations will be noise and distortion free. Stations previously overpowered by strong adjacent signals will sound as steady as if they were alone on the dial. Stations which threw intermittent tantrums of intolerable racket will be pacified.
The TX-II's special circuitry can't make weak stations louder-you'll have to do that with your volume control-but when you do turn up a feeble station it will be clean and clear.
Quartz synthesis. The TX-II uses an incredibly precise circuit which generates a perfect replica of the desired FM frequency and then matches it to the incoming signal for perfect drift-free reception.
Digital tuning ...Digital readout. Touch the UP or DOWN button and the tuner automatically stops at each FM station it can adequately tune.
The TX-II remembers. Not only will it store sixteen stations even when unplugged for up to three weeks, it also remembers the last station you played before it was shut off.
Wide and narrow band selection. In areas with many signals. FM frequency bands can end up close enough to cause interference.
The Narrow setting eliminates bleed-through from other stations without losing frequency response. Use the Wide mode when such interference is not a problem to receive slightly greater dynamic range.
Full instrumentation. Not only does the TX-II digitally display station response, it also reads out six, 10-dB signal strength stops, indicates when the quartz circuitry has closed on a station and when a stereo station has been detected.
How to sell yourself a TX-II. Visit your dealer and ask to hear the most expensive, famous or esoteric tuner he sells. Tune to a multipath-ravaged, hiss filled station and compare the sound to the affordable Carver TX-II. Now press TX-II's Multipath and Noise Reduction Circuits. And appreciate what Carver technology has done for the FM tuner.
Specifications: TX-11
IHF Sens: 1.0uV
50dB Quiet in Stereo: 3 1 uV
Distortion: 05%
THD S/N: 82dB
Freq. Resp: 20Hz to 15kHz +/- 0.1dB
Stereo Separation: 45dB
Alt. Channel Select:
Wide 110dB
Narrow 35dB
Capture Ratio: 1.0dB
Noise Reduction: up to 23dB
Multipath Reduction: 14dB
Dimensions: 17.5"W, 3.5"H, 12.5"D; Weight 11 lbs.
----- ----------- -----
CARVER TX-2
AM/FM STEREO TUNER WITH ASYMMETRICAL CHARGE-COUPLED FM STEREO DETECTOR
If you're tired of having to treat AM and FM as mere background music due to the quality of the signal, you should seriously consider the Carver TX-2. The TX-2's Asymmetrical Charge-Coupled FM circuit makes stereo FM the sonic equal of phonograph records and good cassettes.
Even if the TX-2 didn't have this special circuit, it would be the rival of any tuner you find on the market today. Sleekly styled and ergonomically designed, it has the features which make tuning, holding and adjusting stations as easy as touching a single button.
Not a single knob interrupts the front of the TX-2, for all controls are activated by large, inlaid pressure pads. Touch the power switch and watch the tuning panel come alive. You'll see a crisp, easy-to-read digital tuning read-out.
Automatic scanning and 16-preset memory. Press AUTO, then touch the UP or DOWN button and watch the TX-2 search the dial for strong stations. The LOCKED light will indicate perfect tuning. If it's one of your favorites, just enter it on one of the eight pre-sets pushbuttons. The LED above the button will light, so you can remember its position. Continue until you've picked eight FM stations.
That's probably more than you listen to right now. Because you probably can't GET eight perfect FM signals right now. With the TX-2, you probably can. That under-powered but well-programmed college station. The FM station behind the hill you could never tune just right ... they're all waiting to become presets on the TX-2.
Manual tuning and superb AM, too. The Asymmetrical Charge-Coupled circuit does more than just clear away the hash caused by multipath distortion. It also lets you tune distant stations using the MANUAL control. Find a fascinating but faint signal buried in the background hiss? The TX-2's circuitry goes to work.
Like a curtain rising, the annoying hiss falls way, leaving a clear signal, as accurate and well-modulated as stronger, local stations.
How about AM? You probably don't listen because the quality has been so low. You'll be surprised just how good many stations sound when received through the TX-2. That's why we give you eight AM presets! Most tuners and receivers treat AM like a poor afterthought with only token investment made in circuitry. The TX-2 uses components and design as good as those in its FM section, cutting distortion to below 1% for a crystal-clear signal.
Everything you need to make broadcast part of your listening experience. From the six-stage signal strength indicator to 75 and 300-ohm inputs , the TX-2 gives you everything you need to clean up AM and FM stations' acts. We even provide an easy-to-read manual written like a textbook on how to get the best reception through antenna selection and placement.
Whether you live in a rural area where the FM signals you really like have been too far away or in a crowded urban sculpture of skyscrapers, high-rises and factories which deflect FM like mirrors, the TX-2 represents an opportunity to enlarge your listening horizons.
The TX-2 has also been designed to function as a superb companion to the Carver C-2 preamplifier and the Carver M-200t Magnetic Field Power Amplifier.
Visit your nearest Carver dealer for a personal audition of the Carver TX-2.
Specifications, TX-2
FM TUNER:
IHF Sens:1.8uV
50dB Quiet Sens in Stereo: 5.0uV
Distortion: 2% THD
S/N: 74dB Freq. Beep: 20Hz to 15kHz + .5dB
Stereo Separation: 42 dB
Alt. Channel Select: 58 dB
Capture Ratio: 1.0dB
Noise Reduction: up to 23dB
Multipath Reduction: 13dB
Dimensions: 2.55"H, 17.3"W, 9"D; Weight 9 lbs
AM TUNER:
IHF Sens: 20uV S/N: 55dB
Distortion: 0.9% Selectivity: 42dB
Image Rejection: 45dB
I.F. Rejection: 34dB
AGC Figure Merit: 50dB
---- ----- -------
THE CARVER RECEIVER 2000.
Magnetic Field Amplifier technology.
Sonic Holography.
Asymmetrical Charge-Coupled FM
Detector technology.
Three major Carver technologies in one exquisitely full-featured, remote-control receiver.
Everything necessary for music enjoyment. Settle back in your chair and pick up the Carver Receiver 2000's infrared remote control.
Press the POWER button. Two hundred watts RMS per channel comes alive. Enough to give Compact Discs the impact and clarity they deserve. As the music comes to life, you realize it would be a superb candidate for Sonic Holography. Another touch of the remote control and you're suddenly at the performance, a part of the musical experience. Later on, you select one of your favorite FM stations from the six presets. And then switch to AM stereo for a ball game. All from the comfort of your chair.
The Carver Receiver 2000 has inputs for phono, compact disc player and even video sound sources. It allows 2-1 and 1-2 dubbing through dual tape deck inputs and outputs and selection of two sets of speakers or a combination.
Defeatable tone controls are provided for bass, midrange and treble as well as a preset "loudness" equalization curve for accentuation during low level listening.
The bright digital readout and signal strength LED's are only a hint of the high quality quartz synthesized FM section and AM STEREO circuitry within. Choose from six FM and six AM station presets, tune manually or use the Receiver 2000's automatic station search feature.
From the silky feel of the large, easy to-use knobs, to the unswitched power sockets on the Receiver 2000's back, you'll find that no detail has been overlooked. Even if it didn't have three of Bob Carver's major innovations tucked inside it, the Receiver 2000 would be one of the finest receivers you could own.
----p62 Conventional power amps vs. The Carver Receiver's Magnetic Field Amplifier.
Solid line: audio output signal. Broken line: power supply voltage. Shaded area: wasted power. Vertical lines: power to speakers
Ample Power for Digital. Even before Compact Disc players, clipping distortion has been the critical listener's enemy. Speakers need electricity to move air. They use it to generate magnetic fields inside the voice coils of their drivers. As the coils are repelled by fixed magnets within the speaker, they move outward, pushing the speaker cone with them. It, in turn, transfers that movement to the air in your listening room. A drum beat sounds on the record; energy flows to your speakers: the speakers push the air in some semblance of the original drum beat's impact.
The plain fact is, few receivers have the technical capabilities to provide enough power.
They can translate say, 90% of a musical waveform into the power your speakers need. But just can't deliver that last 10%. Check out the graph in the Magnetic Field Amplifier section of this brochure. You'll notice the top of the impulse has been clipped off. That's where the phrase clipping comes from.
Even though most clipping happens as the receiver is trying to complete a bass waveform, audible distortion is generated in the treble range. Called clipping distortion, these impulses are spikes of non-musical, high frequency power caused as the amplifier hits the bottom of its power reserves. At moderate levels, these spikes veil music with a thin film of distortion that occurs with every musical impulse.
---The Magnetic Field Amplifier draws directly from the source. eliminating bulky power supplies.
Before Bob Carver, the only way to get enough power to completely eliminate clipping distortion was to buy a traditional, brute-force power amplifier design or one of the very few adequately powerful receivers. They are very costly and inefficient because they produce a constant high-voltage level at all times-irrespective of the demands of the ever-changing audio signal. Even when there is no signal to amplify, conventional designs are drawing half power from your electrical outlet and converting it to heat! The Carver Receiver 2000 uses a better way. A method of delivering the power speakers need without heat, bulk and distortion. The solution is elegant and effective.
Imagine a lightning-fast valve on your incoming power outlet. When power is needed, the valve senses the demand and opens, actually using the power of the actual power generator to deliver the needed current and voltage.
Note that this approach provides VAST POWER WHEN NEEDED during peak demands... without keeping excess around during lulls.
The "valve" we've described is the Magnetic Field Coil inside the Carver Receiver 2000. By delivering power only when needed, it can satisfy your speakers' need for power while generating less heat and virtually no distortion.
The finest receiver FM section ever offered. The Carver Receiver 2000 employs Asymmetrical Charge-Coupled Detector technology which makes FM sound as good as other stereo sound sources. Free of background hiss and annoying interference. Even on stations which were previously too weak to enjoy.
FM was designed to be mono, that is, Left plus Right Channel added together (L + R). Later on, when stereo became the rage, an additional signal was added, L R, which carries stereo and ambient information and is decoded by your FM receiver.
Unfortunately, this important second signal (L - R) is extremely prone to mishaps between the transmitting tower and your FM tuner.
These are usually induced by multipath reflections off hills, buildings and the ground, causing more than one L-R signal to arrive at your tuner to confuse things.
The effect is much like that of TV picture ghosting which increases with the number of skyscrapers, and tall hills between you and the tower. Even the most expensive FM tuners are tricked into reading this phase modulation as frequency modulation. In fact. the better the tuning circuit, the more easily it is deceived! The Receiver 2000 can cut through this frustrating problem, though.
It takes advantage of the fact that almost all noise and distortion is in the L-R signal portion. And, for every instantaneous noise or distortion voltage on one channel, there is a replica in the opposite channel.
The Carver Charge-Coupled circuit detects these dirty, mirror images and cancels them before they can reach your ears. They are in effect, "played off against each other" before being compared and combined with the L + R signal and decoded into stereo.
The results are a dramatic reduction in hiss, clicks, pops, picket-fencing and the myriad indescribable, unpredictable noises which often disturb FM listening.
The effect is astonishing. As it was described in a leading audio magazine, "The significance of (this) design can only be fully appreciated by setting up the unit, tuning the weakest, most unacceptable stereo signals you can find, then pushing those two magic buttons.
Separation was still there; only the background noise had been diminished, and with it, much of the sibilance and hissy edginess so characteristic of multipath interference."
True realism with Sonic Holography.
The illusion of stereo imaging is an acquired taste which audiophiles learn to be sensitive to-acclimating to its unnatural perspective in order to enjoy the portrait of sound which the stereo system paints upon the wall between the loudspeakers.
In reality, sound approaches you not just head on but from the sides and from behind. It reverberates through a room, giving you cues as to not only the position of the performers but your position as well. Incidentally, this sort of sonic information is not limited just to classical music recorded in a concert hall. Multi-track pop music also contains ambient and reverberant information. After all, a guitar amp, drum or saxophone are played and recorded in a three-dimensional space. It's just not very apparent listening to stereo.
Sonic Holography presents timing and phase information that now exists in your records, but has been inaudible with normal stereo components. With Sonic Holography, this information emerges in three-dimensional space around the listener. The precise location of instruments and voice can be pinpointed.
You don't need a trained ear to notice the difference. Suddenly the listening field extends wider, higher and deeper than the speakers.
You are literally immersed in the performance.
But don't take our word for it. Begin by reading what major audio magazines had to say about Sonic Holography.
As one reviewer put it, "The effect strains credibility ... the miracle is that it uses only the two normal front speakers." The best of everything in one compact component. There has never been a more complete method of enjoying music than the Carver Receiver 2000. With the power, the tuning ability and the miracle of Sonic Holography this is by far the most capable receiver ever offered. From its remote control to the wealth of tone and switching features, the 2000 lacks only speakers and your choice of sound sources to propel you into the fantastic world of sonic reality.
Specifications: The Receiver 2000
POWER AMP:
Power: 200 W/channel Into 8 ohms, with no more than 0.15% THD
Slew Factor: >100
Frequency Bandwidth: 1Hz to 30kHz +/- 0.1dB
Protection:
Short Circuit
DC Offset
Low/High Frequency Trip
FM TUNER:
IHF Sens: 1.8u V
50dB Quieting Sens in Stereo: 4.5uV S/N: 78dB
Distortion: 1% Freq. Resp: 20Hz to 15kHz t 1dB
Stereo Separation: 45dB
Capture Ratio:1.5dB
Noise Reduction: 7dB
Multipath Reduction:13dB
AM TUNER:
Sens: 20uV S/N: 55dB
Distortion: .6%
Selectivity: 42dB
PREAMP:
Distortion: .05% S/N: 90dB
Freq. Resp: 20Hz to 20kHz + 0.5dB
Phono S/N (MM): 85dB
Phono S/N (MC): 78dB
Phono Input Impedance: 47K ohm
Dimensions: 5.5"H, 19"W, 17.9"D, Weight 33 lbs.
--- -- - - - - - -
THE CARVER RECEIVER WITH ASYMMETRICAL CHARGE-COUPLED FM STEREO DETECTOR
Meet the original Carver Receiver, the one that has stunned critics and audiophiles with its combination of power, features and finesse.
To give you the RMS watts you need for today's recording advances plus virtually noise free stereo FM reception. Carver has designed a receiver with astonishing performance. An instrument designed to make the most of innovations such as stereo/hi-fi video and digital audio discs. An extraordinary synergy of circuitry incorporating two of the high fidelity art's most advanced technological breakthroughs: Bob Carver's Magnetic Field Power Amplifier and his Asymmetrical Charge Coupled FM Detector.
With the Carver Receiver you command 130 watts per channel and a fully digital quartz synthesized AM-FM stereo tuner through a highly sophisticated and meticulously engineered pre-amplifier section.
At your fingertips, the comprehensive control of your entire system. On the front panel: control for turntable, video/audio disc player selection, an auxiliary input selector, and two tape input selectors.
Not only can you individually control bass, treble and midrange tone, but the loudness contour as well. And all tone controls can be taken totally out of the preamplifier circuit for "flat" response.
Choose from two sets of speaker outputs, a combination of both or eliminate them entirely for headphone listening through the Carver Receiver's special headphone amplification circuitry.
Monitor and dub between two sets of tape decks. Match the meter output range to your listening levels. Even switch to mono to detect speaker and cartridge phasing problems instantly.
Pick up to six FM and six AM stations at the touch of a button without having to tune all over the dial. Even activate a special AM filter circuit to cut hiss and sharpness. All in a compact unit no larger than any other conventional receiver lacking the innovations and human engineering Carver has become famous for.
Consider, there are very few 130 watt-per channel receivers on the market today. Frankly, no other company has discovered how to make adequate amplifier power as affordable, light, compact and cool to operate as Carver. Their loss is your gain.
Only the Carver Receiver can surmount the inherent problems of sound reproduction which plague lesser powered receivers at all listening levels.
You see, even at modest listening levels your speakers are making peak power demands which cannot be fulfilled with your existing amplifier. Lightning-fast transients, combinant crests of demand created by multiple waveforms and high intensity-peaks.
Conventional, weaker receivers never deliver enough power, and somewhere, just before each sound pulse is finally formed, it gives out and sends a sort of electronic "note of regret," called clipping. This sharp high-end distortion veils the sound terribly, undoing all the accuracy of recording, cartridge and electronics as well as speakers.
At moderate listening levels, you may not have noticed it. Yet when you sonically compare the Carver Receiver to any other receiver in straight A/B comparisons, you'll INSTANTLY notice the improvement which adequate power makes.
Because it's patented Magnetic Field Amplifier and ultra-sophisticated speaker protection circuitry delivers 130 watts per channel of pure, clean power. So you can truly appreciate your favorite music.
Unlike conventional amplifiers which produce a constant high voltage level at all times, irrespective of the demands of the ever-changing audio signal and indeed even when there is no audio signal in the circuit at all, the Magnetic Field Amplifier's power supply is signal responsive and highly efficient. It produces exactly and only the power needed to carry the signal with complete accuracy and fidelity.
At all times the Carver Receiver monitors your speakers for conditions that could cause damage, allowing them to cool off long before they reach a state which could be damaging.
The same circuits also guard against surges caused by shorts and accidental dropping of the tonearm on a record when the volume is turned up.
These built-in precautions afford you new listening freedom because you don't have to be afraid to unchain the power of the Carver Receiver. Whether you're spinning your original copy of Dark Side of the Moon or a state-of-the-art Compact Digital Disc of the 1812 Overture, you can play it at the volume you want without compromising sound quality or your speakers.
The resulting spaciousness, sonic impact and sheer musicality will invigorate your existing speaker's system, your own ears and those of your friends.
The Carver Receiver also gives you FM stereo performance unmatched by that of any other receiver. As it is transmitted from the station the stereo FM signal is extremely vulnerable to distortion, noise, hiss and multipath interference. In fact, because of the transmission system in use today, the signal to noise ratio of FM stereo has been degraded fifteen times (more than 23 dB!). However, when you engage Carver's Asymmetrical Charge Coupled FM Detector circuit, the stereo signal arrives at your ears virtually noise-free. The result is fully separated stereo with space, depth and ambience! You'll suddenly pull in stations in surprisingly distant cities and suburbs. Underpowered but interestingly programmed college FM stations will be noise and distortion-free. Stations previously overpowered by strong adjacent signals will sound as steady as if they were alone on the dial. Stations which threw intermittent tantrums of intolerable racket will be pacified.
The special circuitry can't make weak stations louder-you'll have to do that with your volume control-but when you crank up a feeble station it will not be submerged in a sea of hiss and multipath.
You will also appreciate the AM section.
Meticulous attention to a very aspect of tuner performance gives you an AM section with true high fidelity response. You will not find another receiver with such high performance anywhere.
The Carver Receiver has been designed for serious music listeners who seek fidelity, accuracy and musicality.
We know you will want to visit your nearest Carver dealer for a personal audition of this remarkable instrument.
Specifications--The Carver Receiver
POWER AMP:
Power: 130 W/channel Into 8 ohms, with no more than 0.05% THD
Power at Clipping: 157 W/channel into 8 ohms
Slew factor: >80
Frequency Bandwidth:1Hz to 30kHz ± 1dB
Protection:
Short Circuit
DC Offset
Low/High Frequency Trip
FM TUNER:
IHF Sens: 1.8uV
50dB Quieting Sens. In Stereo: 4.5uV
S/N: 76dB
Distortion: .2%
Freq. Resp: 20Hz to 15kHz +/-1dB
Stereo Separation: 42dB
Capture Ratio: 1.5dB
Noise Reduction: 7dB
Muitipath Reduction: 13dB
AM TUNER:
Sens: 20uV S/N: 55dB
Distortion: 0.9%
Selectivity: 42dB
PREAMP:
Distortion: .05%
S/N: 90dB
Freq. Resp: 20Hz to 20kHz + .5dB
Dimensions: 5.7"H, 17.3"W, 17.9"D, Weight 28.6 lbs.
--- ---- ----
THE CARVER RECEIVER 900 WITH ASYMMETRICAL CHARGE-COUPLED FM STEREO DETECTOR
The Carver 900 is-in terms of power-the smallest of the Carver Receivers. However no other product currently offered by any other manufacturer delivers the same amount of power, features, specifications or out-and-out performance found in the Carver Receiver 900. The Carver Receiver 900 sets standards which are unapproachable by any other comparably priced receiver. Because even with their "smallest" receiver, Carver has created a component which is truly powerful, musical and accurate.
No other receiver in this class has a clean NINETY watts per channel FTC. Moreover, no other receiver can deliver a stunning 180 watts during the dynamic peaks that Digital demands.
And no other non-Carver receiver can resolve noisy FM into a clean, clear signal comparable to disc sources.
How many stations do you normally listen to? The Carver Receiver 900 can remember eight AM and eight FM stations. Just touch a button to switch between your favorites. Is the station noisy or weak? Engage the Carver Asymmetrical Charge-Coupled Detector and resolve interference-prone and distant stations into rich, full stereo. Suddenly your listening possibilities are vastly increased. No other brand of receiver has the technology to combine quartz-synthesized digital FM with added circuitry to solve the real-world interference problems that are present across the landscape. Naturally the 900 includes memory preset, auto-seek and manual scan as well as an accurate LED signal strength meter and stereo indicator.
At ninety watts per channel RMS, the Carver 900 provides serious power for today's new acoustic suspension speaker designs.
Power to resolve records and tape with new impact and clarity. Power to ignite your imagination with a digital disc! Either way, Carver's smallest" receiver will deliver pyrotechnic dynamics and freedom from clipping distortion that will render your favorite music with new clarity.
And of course the Carver 900 Receiver has The Right Features. You've eschewed separates because you like the combination of controls and features found on an all-in-one receiver, right? You'll soon discover that the Carver 900 delivers them all. Generous, human-engineered volume control with a silky feel you won't find on anything but larger Carver receivers. Defeat able center-detented bass and treble control.
Large easy-to-use program source controls for CD's, FM, AM, Phono, and VIDEO sound inputs. Tape dubbing for 1:2 and 2:1 sources.
Precision balance, loudness control and mono button. Dual speaker outputs. Switched and unswitched AC receptacles. Even a separate headphone circuit and output jack. The Carver 900 gives you everything you need to outdistance any comparably-priced receiver. Moreover, the 900 once-and-for-all settles the argument as to which modestly-priced receiver gives you the most features, power and noise free FM reception.
Specifications—Receiver 900
POWER AMP:
Power: 90 W/channel into 8 ohms, 20Hz to 20kHz, with no more than 0.15% THD
Power at Clipping: 108 W/channel at 8 ohms
Slew Factor: >68
Frequency Bandwidth: 1Hz to 30kHz +/-1db
Protection:
Short Circuit
DC Offset
Low/High Frequency Trip
FM TUNER:
IHF Sens: 1.8uV
50dB Quieting Sens in Stereo: 5uV
S/N: 74dB
Distortion: .2%
Freq. Resp.: 20Hz to 15kHz +/-1dB
Stereo Separation: 40dB
Capture Ratio:1.0dB
Noise Reduction: 7dB
Multipath Reduction:13dB
AM TUNER:
Sens: 20uV
S/N: 55dB
Distortion: 0.9%
Selectivity: 42dB
PREAMP: Distortion: 0.05
S/N: 90dB
Freq. Resp.: 20 Hz to 20kHz +/- 1db
Dimensions: 4.33"H, 19"W, 17.9"D, Weight 26 lbs.
--- --- ---
DIGITAL TIME LENS TECHNOLOGY AND COMPACT DISCS.
Compact Discs represent the first significant improvement in audio sound sources since the stereo phonograph record. You don't have to be a "golden ear audiophile" to instantly perceive the remarkable sonic improvement.
Still, one must view digital sound with the same historical perspective applied to such breakthroughs as stereo, transistor amplification and FM broadcasts. Each was demonstrably better than what preceded it. And yet each had shortcomings which were improved later on, when the initial blush faded.
Just as Bob Carver has enhanced FM reception, power amplification and the effect of stereo, so he has taken digital Compact Disc sound to its next plateau with Digital Time Lens Technology.
While hundreds of articles and reviews have been written on the digital audio recording process, it is valuable to review just how the process works in theory to better appreciate the Digital Time Lens' further contribution.
Analog recording uses magnetic tape to record varying amounts of musical signal. The more musical impulses in a given passage of music, the more magnetism is imparted on that portion of tape passing the recording head.
While this recording method has given us thirty years of memorable recordings, it labors under at least five physical limitations which cause audible degradation of the signal. 1) Tape has finite limits as to the amount of energy it can record. Saturation and distortion occur when the limit is reached, yet musical dynamics extend far louder and softer than the medium can handle.
2) Magnetic tape, by its very composition, imparts some internal energy which we hear as hiss. Thus quiet parts of recordings can suffer from annoying background noise. 3) it is very hard for tape to deal with extremely high and extremely low frequencies, again due to physical realities of tape oxide composition, speed and head configuration. 4) Even if problemsl-3 are minimized, the result gets scratched into the surface of a piece of plastic and played back by letting a small diamond wiggle around in the groove. Not theoretically the best method by any stretch of the imagination. 5) Even if said grooved plastic disc is the best virgin vinyl and the wiggly diamond is a $1000 handmade cartridge on a $2000 turntable, the record can come to a bad end in seconds at the hands of a)a five-year-old with a peanut butter sandwich, b an inquisitive pussycat, c) your best friend after half a bottle of Cabernet.
Digital recording gets around all of these problems. The musical signal is sampled and analyzed by a computer which, in effect, impartially measures the signal with a ruler. It is recording impartial digital comments such as, "This segment is VERY loud+98dB-and goes down to 20Hz." "This segment is extremely quiet and contains a flute solo with harmonics to19,000Hz." "This segment increases in dynamics by 60dB in less than a hundredth of second, etc." Instead of trying to make a physical model of these measurements the way analog tape does, digital recording simply "prepares a report," coded in l's and 0's much the way a floppy disc can contain the text of a book encoded in binary language.
The Compact Disc playback unit "reads" the report and changes the sound back to analog musical impulses which are fed into your hi-fi just like a tuner, cassette deck or phonograph source. Except that the digital source will be free of background hiss, contain the full range of frequencies from deepest fundamentals to almost inaudible highs and provide dynamics ranging from gossamer-soft to thunderstorm loud.
Since it's not limited by actually trying to emulate the musical signal, more sheer excitement, sonic impact and definition of individual instruments reaches your preamplifier. Unquestionably digital has proved a quantum leap ahead of previous recording and playback methods. You might compare it to a good stereo disc versus an Edison wax cylinder. That's how much better a Compact Disc can be than the average vinyl recording. Still, this wonderful process has received some qualified criticism from experts who have extremely good ears. Many professional musicians, audiophiles and audio journalists, while praising the quietness and dynamic range of Compact Discs, have often expressed a lingering disappointment in the way music itself sounds on many commercial examples. This is particularly evident when the compact disc is compared with a well-executed analog counterpart. The complaint boils down to a lack of ambience and spatial detail, along with a midrange which often has been described as sounding bright, hot and harsh.
When Bob Carver received his first Compact Disc player, he too was not prepared for the compromises in sound he heard on some discs.
The three-dimensional perspective which his analog system provided in lush abundance on phono discs evaporated into a flat, brittle wasteland. The next day, he purchased no less than 23 Compact Discs and their analog, vinyl counterparts and set about quantifying the differences.
As expected, the CD discs were quieter, exhibiting better dynamic range and richer, tighter bass. But testing uncovered two inherent flaws: 1) Different spectral energy balance. The overall frequency response was shifted on the CD towards more midrange above 400 Hz; 2)
The amount of Left-minus-Right channel Information versus the amount of Left-plus-Right differed by about 1.25dB between analog and digital.
It is important to understand that the Left minus-Right (LR) component of stereo carries the three-dimensional part of sound field information, much as is done with FM stereo (refer to the section on Carver's tuner circuitry). A deficiency of1.25dB doesn't sound like much.
But since power goes up as the square of the voltage, it means that analog records carry a whopping thirty-three percent more ambience information than digital discs. That's a noticeable reduction in three-dimensionality, imaging and other psychoacoustic factors that put the realism into music.
How does the Digital Time Lens correct these problems? Bob Carvers circuitry adjusts
the ratio of L R to L + R and restores the octave-to-octave balance originally intended by the musician and recording engineer as evidenced by the analog recording.
More specifically, Bob discovered that the L + R component of a digital disc had to be equalized somewhat differently than the L-R component of the digital disc so that it would match the analog disc (the analog version of the same musical recording). There were two equalization curves necessary to make the digital disc sound the same, exactly the same as its analog counterpart. In addition to equalizing the L + R band and the L-R band independently, it was necessary to increase the level of the L-R band so that it would match the L-R level that was on the analog disc.
Now, since the equalizations were different for the two bands, it was necessary to introduce a time correction in the L + R band because the equalization was steeper in the L-R and so the signal would go through the L-R with a greater group delay than it would go through the L + R signal chain and would arrive out of step, so a compensating delay, just micro-seconds, is employed in the L + R signal chain so that when the two signals arrive at the matrix to be turned back into left signal and right signal, they arrive without time domain errors.
The Digital Time Lens, Theory and Practice.
Bob Carver, along with many others, was displeased by the sound of the earliest CD's and decided to find out why some didn't sound the same as the LP versions of the same recordings. Unlike many who have complained about poor stereo imaging, lack of depth and strident, harsh treble--and who have blamed the CD digital system itself-Carver was enough of a mathematician and engineering theorist to know that the system itself was inherently blameless.
After extensive comparison tests between LP's and their CD versions, which included time-synched playings of both types of record while measurements and observations were made, Bob concluded that there were two major differences between certain CD's and their LP equivalents. The first had to do with stereo depth or separation. In any stereo program, the stereo effect is transmitted by the difference between left and right signals.
Bob discovered that many CD's have less relative L-R information than do the LP's for the same programs at the same musical moment.
In order to see it, Bob devised a special test circuit that would amplify the difference. The figures show the Lissajous patterns obtained from the same instant of musical program in its LP (fig B2) and CD (fig B3) versions.
Fig. B2--Lissajous pattern showing (L-R)/ (L + R) ratio from an LP record.
Fig. B3--The same instant of music as in Fig. B2 but taken from the CD version. Note the decreased difference (L-R) content, as shown by the narrowed trace.
In this type of display, a straight, thin diagonal line from the lower left to the upper right would represent a purely monophonic signal. The more stereo "difference" information there is, the more the line spreads out into an ellipse.
Notice that there is significantly more difference (L-R) signal in the LP version of the music! The second major difference noted by Bob Carver between some CD's and their LP counterparts was a difference in equalization, or the overall frequency response. Using a fine moving-coil cartridge to play the LP versions of certain programs, Carver noted that there was a slight BOOST in the mid-bass region and a slight CUT in the mid-treble region compared with the response obtained when playing the CD version of the same program.
Bob's objective in designing the Digital Time Lens was to give the user the ability to introduce the converse of the two effects at will. That essentially is what he has done: If there is a deficiency of L-R signal in some CD's, the user can interpose a form of matrix/dematrix circuitry that will put back some of the extra L-R signal. If there is overly bright mid-treble and somewhat diminished mid-bass in a CD, the user can add a little mid bass and attenuate some mid-treble frequencies by means of a switchable circuit. L.F. Reprinted by permission from Audio Magazine, © CBS Publications, 1985.
If you have read the excerpt from Audio Magazine included on this page, you will note that the reviewer qualified his comments by noting that not all CD's need the beneficial effect of the Digital Time Lens.
We concur. Later on in the review, the same reviewer noted, "I suspect that many owners will ... put little marks on their CDs that indicate whether they should be played with the Time Lens or not. I find nothing wrong with such an arrangement." Again, we concur. It took a lot of courage on Bob Carver's part to play the part of the truthful child confronted with the Emperors’ new clothes, the part of the person with the courage to point out that digital could often sound better.
But unlike a mere critic, Bob Carver has done something about the shortcomings he perceived. He has given every music lover the final tool necessary to open up an exciting new world of sound.
CARVER DIGITAL TIME LENS
You can't buy a better CD Player than the Carver CD Player. Impartial magazine reviews prove it. Qualified listeners prove it. Your own ears will prove it in a demo at your Carver Dealer.
Unfortunately, some of you already own Compact Disc Players. There is a solution.
The outboard Digital Time Lens adds the finishing touches of sonic accuracy and realism to Compact Digital Audio Discs. It turns an innovation into near musical perfection.
If you are willing to make a commitment to vastly improving your sound source with a Compact Digital Disc player, you should also go the short extra step that lets digital realize its true potential.
That step is a Carver Digital Time Lens, connected between your CD player and preamplifier.
Visit your nearest Carver dealer and ask for a demonstration of how we've "focused" digital playback into a crystal-clear image of the original performance.
Input: 2 v. 50k ohms Impedance Output: 2 v.
Distortion: 0.005%.
Frequency Response: 20 Hz-20 kHz
Dimensions: 17 1/4" wide, 4" deep, 11" high.
Line Voltage: 120 VAC 60 HZ Dither signal: 0dB - 70 dB adjustable.
THE CARVER COMPACT DISC PLAYER WITH DIGITAL TIME LENS
How logical it is for a company dedicated to delivering music with maximum dynamic impact to offer a state-of-the-art CD player. Anyone who ever wondered why Carver makes amplifiers capable of delivering hundreds of watts of power need wonder no longer after they have heard the Carver Compact Disc Player as a sound source.
There are dozens of brands of Compact Disc players available right now, many of them rushed to market as "me too" line extensions with little regard for the finer technical points of digital playback technology. Carver was in no hurry. They wanted to do digital right.
Because the state of the art has advanced considerably since the first players appeared several years ago. Unlike many of the "off brand" models now available which employ less advanced technology, the Carver Compact Disc Player makes use of the latest triple laser beam pick-ups and sophisticated oversampling and digital filtering technology.
Except for features like display and programming, the real determining factor in CD player quality is its ability to reconstruct music from digital information bits. And that is not an easy job nor one that can be effectively achieved while skimping on circuitry.
The Carver Compact Disc Player reads discs with more precisely focused laser power than most other models, resulting in improved tracking and less chance of drop-outs when dust or smudges are encountered on a CD. Along with a potentially audible signal ranging up to 20kHz, there are endless images of the signal at 40K, 80K, 160K etc. While they are above the range of human hearing, they must be removed from the signal to prevent harmonic problems which could turn into audible distortion. Earlier CD models placed an anti-imaging filter after the digital/analog converter stage. Carver uses DIGITAL filtering ahead of the D/A converter through a process called double oversampling. The signal is passed through a shift register which delays the samples, so that the weighted average of a large number of signals is generated. Through a complicated process. frequency bands are suppressed between 20kHz and 160kHz. eliminating harmonic distortion problems early on before the complicated D/A translation.
The same oversampling process also distributes the same amount of noise over twice as wide a frequency range, resulting in half as much noise in the final signal. Then after translation to analog, the signal is once again filtered for a gentle roll-off above 17kHz that imparts à more natural musical sound to the final output.
One of the important tests applied to determine the effectiveness of digital-to-analog translation circuitry is the reproduction of a square wave. When Audio Magazine applied this test to the Carver Compact Disc Player. their test equipment displayed the following: One doesn't need an engineering degree to recognize the accuracy of the Carver Compact Disc Player's output. The reviewer observed that "Reproduction of a I-kHz digitally generated signal was as close to a true square wave as have ever seen from a CD player that used digital filtering. (The Carver Digital Disc Player) shows a virtual absence of phase error." On top of this unerring ability to produce warm, real-sounding music from the CD's digital bits, the Carver Compact Disc Player has the remarkable Digital Time Lens circuit which can further enhance your listening enjoyment.
When Bob Carver received his first Compact Disc player, he was surprised at the sound derived from some discs. The three-dimensional perspective which his analog system provided in lush abundancy on phono discs evaporated into a flat, brittle wasteland. After extensive testing. Bob had uncovered two inherent flaws in some but not all Compact Discs: I) Different spectral energy balance. The overall frequency response was shifted on the CD towards more midrange above 400 Hz: 2) The amount of Left-minus-Right channel information versus the amount of Left-plus-Right differed by about 1.2 5dB between analog and digital.
Bob Carver's circuitry adjusts the ratio of L-R to L + R and restores the octave-to octave balance originally intended by the musician and recording engineer as evidenced by the analog recording.
In addition, the L + R component of a digital discs is equalized by the Digital Time Lens differently than the L-R component and the level of the L-R band is increased slightly to enhance ambient effects found on corresponding analog discs.
The result is a warmer sound with more of the three-dimensional am Tent information that places us in the same space with performers.
You won't need the Digital Time Lens on all CD's. But it is there when you need it. And only on the Carver Compact Disc Player.
Ease of operation is a hallmark of Carver components and the Carver Compact Disc Player is no exception. A subtle but easy-to-read LCD display not only shows selection number, elapsed time and total time of the CD. but also "talks" to the user. Turn on the Carver Compact Disc Player and the display asks for a disc. When the disc tray is open, the display reminds you with an OPEN readout. When a CD has completed playing, the multi-function display reads END. With the Carver Compact Disc Player's Programmable Random Access Playback System, track search and programming of up to nine different selections is a snap, as is automatic repeat of a previous selection or an entire CD. For classical music lovers, the Carver Compact Disc Player has complete indexing capabilities as well.
The large, easy-to-use feather-touch controls include pause, fast forward and reverse.
You can even monitor music at high speed to find a certain portion of a selection.
If you really enjoy music, you owe it to yourself to begin your digital experience with the only full-feature CD player that has the Carver touch. The only CD player that can actually improve on what is already the best playback medium ever offered.
Audition the Carver Compact Disc Player with Digital Time Lens at your Carver dealer soon.
Specifications Frequency response: 5Hz-20kHz THD: 0.5% Signal-to-noise ratio: 96dB Output voltage: 1,9V Channel Separation: 86dB ¡à 1kHz Dynamic Range: 96dB
CRITICAL ACCLAIM
"Bob Carver is definitely an audio and r. f . genius." (Leonard Feldman, Audio Magazine)
THE MAGNETIC FIELD POWER AMPLIFIER
The technology of the Carver Magnetic Field Power Amplifier solves some of the most basic problems of conventional power amplifiers: high cost, great weight, and excessive heat generation.
The Carver M-400t is the first amplifier to utilize this technological breakthrough. A 200 watt per channel amplifier in a seven-inch cube weighing less than ten pounds, the M-400t is powerful, accurate, and musical.
"Its distortion and noise levels are entirely negligible. It is hardly conceivable that a small, inexpensive, lightweight cube such as this could deliver as much clean power as any but a few of the largest conventional amplifiers on the market-but it does ... An important new amplifier design." (Hirsch-Houck Labs in Stereo Review)
Music reproduction was superb and completely free of any false bass coloration or muddiness. The amplifier handled the toughest transients we were able to feed it, with ease. It is, to put it mildly, quite an achievement and one that is likely to change the way many of us think of power amp design in the future." (Leonard Feldman in Audio)
When Ovation Magazine reviewed the M-500t, they reported: "The amplifier just doesn't look big enough or heavy enough to deliver the kind of power that it claims. But after listening to it for a while, we found ourselves opening it up "full throttle," and only then did we appreciate Bob Carver's remarkable achievement. The amplifier's sound quality is excellent: it need not take second place to even the most esoteric and costly amplifiers in that regard. Listening to its tight, clean bass and its well-balanced, uncolored midrange and treble reproduction, one tends to forget that the cost of that power-on a "dollars per watt" basis, is only $1.11 per watt."
Of the Carver M-1.5t, Peter Aczel, Editor and Publisher of The Audio Critic has said, " .. . the equal of any power amplifier in transparency, focus and smoothness and, of course, far ahead of any other we tested in sheer gut shaking power and dynamic range. We especially enjoy hearing spatial detail, instrumental definition and completely natural dynamics on familiar records to a degree we did not know was extractable from the grooves when we listened through lesser amplifiers. At this level of sonic performance, the astoundingly small size and cool operation of the M-1.5t become the icing on the cake, rather than the main attraction."
SONIC HOLOGRAPHY
The problems of sonic imagery inherent in conventional stereophonic reproduction have been solved by the Sonic Hologram Generator, available in three different components: The C-4000 and C-1 Preamplifiers and the C-9 Sonic Hologram Generator.
Very briefly, the Sonic Hologram presents timing and phase information that exists in stereo program material-but is normally inaudible. With Sonic Holography, this information emerges in three-dimensional space around the listener who is thus able to' establish the precise location of the instruments and voice.
The impact on the listener of Sonic Holography is best described by the most experienced and knowledgeable experts in the audio industry.
"When the lights were turned out we could almost have sworn we were in the presence of a real live orchestra." Hal Rodgers, Senior Editor, Popular Electronics "The effect strains credibility-had I not experienced it, I probably would not believe it ... the 'miracle' is that it uses only the two normal front speakers." Julian Hirsch, Hirsch-Houck Labs, Stereo Review " ... it brings the listener substantially closer to that elusive sonic illusion of being in the presence of a live performance." Larry Klein, Technical Director, Stereo Review " ... seems to open a curtain and reveal a deployment of musical forces extending behind, between and beyond the speakers,., terrific." High Fidelity "Instruments and performers are located where they belong whether to the front of, between, beside or behind the speakers--in sort, anywhere in a 180 degree arc facing the listener." Omni Magazine "The effect is both impressive and exciting to experience." Stereo Review
BREAKTHROUGH IN FM STEREO RECEPTION
Carver's most recent technological breakthrough is the Asymmetrical Charge-Coupled FM Detector circuit, a special feature of the Carver TX-II FM Stereo Miner.
This unique circuit drastically reduces multipath and distant station noise, while providing fully-separated stereo reception with space, depth and ambience.
The TX-II has received unprecedented acclaim from reviewers: "It is by a wide margin the best tuner we have tested to date." "What distinguishes the TX-II is its ability to pull clean noise-free sound out of weak or multipath ridden signals that would have you lunging for the mono switch on any other tuner we know of." High Fidelity Breakthrough in FM tuner performance: Carver TX-II."
"The significance of its design can only be fully appreciated by setting up the unit, tuning to the weakest, most unacceptable stereo signals you can find, then pushing those two magic buttons."
"Separation was still there: only the background noise had been diminished, and with it, much of the sibilance and hissy edginess so characteristic of multi-path interference."
"A tuner which long-suffering fringe area residents and those plagued by multipath distortion and interference have probably been praying for ... "
Leonard Feldman, Audio
“.. enjoy the music and forget about noise and distortion." "Under conditions of weak signal stereo reception the effectiveness is almost magical." Ovation "A major advance ... "Its noise reduction of stereo reception ranged from appreciable to tremendous." "It makes the majority of stereo signals sound virtually as quiet as mono signals, yet it does not dilute the stereo effect."
Julian D. Hirsch, Stereo Review
THE CARVER RECEIVER
The 130 watt per channel Carver Receiver which incorporates both the technology of the Magnetic Field Power Amplifier and the Asymmetrical Charge Coupled FM Detector has also received unprecedented praise from the reviewers.
"The Carver Receiver is, without question, one of the finest products of its kind I have ever tested and used." Leonard Feldman, Audio Magazine "I consider the Carver Receiver to be the
'most' receiver I have yet tested in terms of the quantitative and qualitative superiority of almost all its basic functions." Julian D. Hirsch, Stereo Review
THE CARVER COMPACT DISC PLAYER WITH DIGITAL TIME LENS
The Carver Compact Disc Player has been acclaimed for its sound quality as well as for its technology.
Carver CD Player: Superb Sound plus the Digital Time Lens (From the cover of Audio Magazine)
"Leave it to Bob Carver to come up with a CD player designed to please both those who love CDs and those who still have reservations about their sound quality." "It almost goes without saying that the sound quality produced by this player was superb-without the Digital Times Lens. So, what did the Time Lens contribute? I look upon this circuit as an option, one that can and should be used with certain CDs which seem to lack the depth that I feel belongs in a musical performance." Leonard Feldman, Audio Magazine
"Suddenly, tonal balance seemed more correct and less strident, and what seemed like a two-dimensional stereo effect appeared to "open up" to some degree-affording the three-dimensional perspective that the musical performances demanded.
"Here, then, is an excellent CD player that provides an option you won't find on other compact disc units." Ovation Magazine.
E
(Audio magazine, Oct. 1985)
Also see:
Carver TX-11 FM Stereo Tuner (Dec. 1982)
Carver Digital Time Lens Technology and Compact Discs (Oct. 1986)
= = = =