NEW PRODUCTS--THE LATEST IN HIGH-FIDELITY EQUIPMENT
Harman/Kardon 44+ CD-4 Demodulator
AN add-on demodulator that, in combination with an appropriate phono car tridge, will give CD-4 capability to any four-channel system is being marketed by Harman/Kardon as the Model 44+.
The demodulation circuitry is automatically switched in by the presence of the CD-4 carrier on the record, which also illuminates a CD-4 pilot light on the front panel. A function selector chooses either the CD-4 mode or a STEREO/MATRIX position, in which the unit simply amplifies and equalizes the output of the cartridge just as do the phono inputs of an amplifier or receiver. A third position, labeled BYPASS, routes the unaltered signal from the cartridge to a pair of special outputs intended to be connected directly to the phono inputs of an amplifier or receiver.
In CD-4 operation, the frequency response of the 44+ is 20 to 10,000 Hz ±1.5 dB; response is down 5 dB at 15,000 Hz due to the action of the de modulator's filter. Signal-to-noise ratio is 60 dB, and separation between channels exceeds 20 dB. The sensitivity of the inputs is 2 millivolts, with an impedance of 100,000 ohms and less than 30 picofarads capacitance. The unit has dimensions of 5 1/4 x 41/8 x 14 inches overall. Price: $119.95.
Wollensak Model 4775 Stereo Cassette Deck
THE new Model 4775 is the first stereo cassette deck from Wollensak to offer built-in Dolby noise reduction in the form of a single integrated circuit (IC) for each channel. The control facilities use push keys for transport operation and RECORD mode, and toggle switches for tape selector ("regular" or chromium-dioxide), mono/stereo recording, Dolby, power, and input selector.
The deck also has a memory-rewind feature operating in conjunction with the three-digit index counter and an automatic end-of-tape shutoff. Microphone and line input signals can be mixed.
Specifications for the 4775 include: frequency response, 40 to 17,000 Hz ±3 dB with chromium-dioxide tape, 40 to 13,000 Hz ±3 dB with regular tape; wow and flutter, 0.13 percent; signal-to-noise ratio, 52 dB without Dolby (Dolby improves S/N by 10 dB above 5,000 Hz).
The microphone inputs will accept low-impedance microphones. The Model 4775 measures approximately 16 x 51/2 x 19 inches; it is supplied with wood base and Plexiglas dust cover. Price: $285.95.
Beyer M550S Omnidirectional Dynamic Microphone
A relatively inexpensive moving-coil microphone is being offered by Beyer Dynamic. The Model M550S is an omnidirectional design with a frequency response of 50 to 16,000 Hz ±2.5 dB.
The sensitivity of the microphone, referred to the standard sound-pressure level of 0.0002 dyne per square centimeter, is -53 dBm at 1,000 Hz. Overload does not take place even at sound-pres sure levels in excess of 135 dB. The microphone is suitable for use with all load impedances.
Each M550S comes with its own individual calibration curve. The microphone is finished in black, with an on/off switch built into the case. An integral 15-foot cable is included, terminating in a standard phone plug. A small tripod stand and clamp assembly is also sup plied. Price: $37.50.
Fisher 634 AM/FM Four-Channel Receiver
THE Model 634 is Fisher's largest and most elaborate four-channel receiver, providing a continuous power output of 45 watts per channel, all four channels driven simultaneously into 8 ohms.
Connecting the amplifiers together for stereo operation yields a continuous output of 110 watts per channel. Harmonic distortion is 0.5 percent and intermodulation distortion 0.8 percent, both at rated output. The 634 has a built in demodulator for CD-4 discs and an SQ decoder with several types of logic assistance (full wave-matching and vari able blend) that can be individually switched in by the user. Discrete four-channel sources are also accepted through the tape and auxiliary inputs.
Two sets of phono inputs are provided, one of which gives access to the CD-4 circuits. The CD-4 separation controls are located to the far left of the front panel. Signal-to-noise ratios are 65 dB for the phono inputs, and 70 dB for high level inputs.
The principal controls of the 634 are a master volume knob, joystick balance control, and four small individual- channel level controls for preliminary channel balance. Tone controls for bass, treble, and mid-range provide for separate adjustment of the front and rear channels (in the case of bass and treble) and left and right channels (in the case of the mid-range controls). The speaker selec tor chooses between two sets of speakers or silences all speakers for head phone listening (stereo headphone jacks for front and rear channels are located on the front panel). Three dual-pointer meters also appear on the front panel.
Two of the meter movements indicate signal-strength (AM and FM) and channel-center (FM) tuning, and the other four register the levels of the four channels. The sensitivities of these meters can be reduced by means of a pushbutton switch. Other pushbuttons introduce high- and low-cut filters and FM inter-station-noise muting, and select operating mode.
FM specifications for the Model 634 include an IHF sensitivity of 1.8 micro volts, capture ratio of 1.2 dB, 55-dB AM suppression, 90-dB spurious-response rejection, and 65-dB image rejection.
Alternate-channel selectivity is 60 dB, and stereo separation is 38 dB at 1,000 Hz. Stereo FM harmonic distortion is 0.4 percent. The receiver measures 23 3/8 x 7 1/4 x 15 7/8 inches. A wood cabinet is supplied. Price: $799.95. An optional cable-connected remote controller ($29.95) plugs into the back of the receiver and adjusts volume and balance.
Kenwood Automatic Single-Play Turntables
A new line of turntables consisting of two automatic single-play models has been introduced by Kenwood. The top model, the K P-5022 (shown), employs a direct-drive motor that rotates at the actual platter speed, with illuminated stroboscopic markings along the platter's circumference and fine-tuning speed adjustments with ranges of ±3 percent around either of the turntable's two speeds (33 1/3 and 45 rpm). The Model K P-3022 is similar, but a synchronous motor drives the platter through a belt linkage, and the strobe markings and speed adjustments are lacking. Both models have tubular aluminum tone arms of elliptical cross section. These are equipped with their own motors for the automatic functions (indexing to a preselected record diameter, and raising and returning to rest at the end of a record). The turntable can also be operated manually. Arm balance and tracking force adjustment are accomplished through two counterweights. Anti-skating is applied separately by means of a calibrated knob control. Stylus overhang and azimuth are adjustable right at the head shell, where the cartridge holder is clamped to the main body of the tone arm. The pilot lamp on the motorboard serves as an index for making the over hang adjustment.
Wow and flutter for the Model KP 5022 are less than 0.05 percent, and rumble level is below-58 dB. Corresponding specifications for the KP-3022 are 0.08 percent and-48 dB. The bases of both units are constructed of ABS res in with simulated wood finish, within which the turntable motor-boards are floated on spring suspensions. Approximate overall dimensions, including the transparent hinged dust covers supplied: 19 x 6 3/4 x 13 2/3 inches (K P-5022): 17 3/4 x 6 3/4 x 14 2/3 inches (K P-3022). Prices: KP-5022.$299.95: KP-3022, $199.95.
Dual 901 Auto-Reverse Stereo Cassette Deck
THE new Model 901 stereo cassette deck from Dual provides automatic-reversing operation in both the playback and recording modes, as well as a continuous-play mode that repeats both sides of a cassette indefinitely. The transport employs twin capstans-one for either direction-and erase heads on both sides of the single permalloy record-playback head. When the deck is in motion, only the capstan and erase head for the direction selected come into contact with the tape. The 901 has built-in Dolby noise reduction with external calibration adjustments for standard and chromium-dioxide tapes. In addition, the newer chromium-dioxide cassettes with mold ed coding slots on their cases will automatically switch the deck's recording characteristics to suit this tape type (manual switching is also possible with cassettes lacking the slot).
The recording-level meters of the Dual 901 have true VU characteristics.
They are supplemented by a peak-indicator light that glows to indicate brief signals that would exceed 0 VU on the meters. To prevent overload effects on such peaks, an automatic level control can be switched in to limit excessive signals. The dual recording-level controls are of the slider type. In addition, micro phone inputs (for dynamic microphones from 200 to 700 ohms impedance and for condenser microphones) and a stereo headphone jack suitable for low-impedance phones are provided. The cassette-eject mechanism is viscous damped.
Specifications for the Dual 901 include a frequency response of 20 to 14,000 Hz with standard tape, 20 to 15,500 Hz with chromium dioxide, both ±1.5 dB. Wow and flutter are less than 0.09 percent, and the signal-to-noise ratio exceeds 50 dB without Dolbyizing, 59 dB with Dolby processing. At a re cording level of-2 VU at 1,000 Hz, harmonic distortion is less than 1.5 percent. The deck can be operated in any position, and hanging slots for wall installation are provided, as well as feet which make it possible to stand the deck on edge. Dimensions are 16 1/2 x 4 1/2 x 11 1/4 inches. Price: $450.
TDK "Audua" Open-Reel Tape
THE "Audua" series of open-reel sound-recording tapes just introduced by TDK is reportedly the result of several improvements in magnetic-tape manufacture developed by the company. Exceptionally small iron-oxide particles are used (0.4 micron wide and roughly 4 microns long, for a length-to-width ratio of 10 to 1) in a dense coating with improved particle orientation. The result is an oxide coating with excellent overload characteristics at high audio frequencies.
According to TDK, output is approximately 2 dB greater at 10,000 Hz than that of conventional tape (optimum bias assumed), with further improvements at higher frequencies. The recommended bias for Audua tape is 25 percent higher than standard. The tape employs a polyester base material and comes in lengths of 1,200 and 1,800 feet on 7-inch reels, 3,600 feet on 10 1/2-inch reels. Prices for the three lengths (L-1200, L 1800, L-3600): $8, $10.50, and $31.50.
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Also see:
AUDIO QUESTIONS and ANSWERS--Advice on readers' technical problems, LARRY KLEIN