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Like everything else, a stereo system is subject to the laws of entropy and will in time drift out of tune. Maintaining a system properly not only ensures a high level of performance but also mitigates wear and tear. Ignoring good maintenance ensures slow degradation of sound quality—occurring so gradually that you may never be aware of why you find yourself less and less drawn to listening to music and less and less satisfied when listening.
It is at this point that many systems are scrapped as being “out dated” and replaced in toto, at sizable expense. This is a great mis take—what was once a good component remains always a good component. Better ones may be developed, and the “best” may be surpassed, but nonetheless once good remains always good.
The mind can psycho-acoustically compensate for a bad-sounding stereo, as is demonstrated by the dominance of mid- and mass-fl and the awful sound of most TVs and of telephones. Accomplished musicians are notorious for owning disgraceful sound systems. Musicians find stereo so unbridgeably distant from live music that they see no point in even trying to narrow the gap. Few, as a result, have ever heard a good system.
The point is that just because you think your system sounds OK doesn’t mean it couldn’t benefit from proper maintenance. The time, labor, and money involved are minimal and you may be pleasantly surprised, even astonished, by the results.
Connections and Switches
Maintenance is, as much as anything, a matter of keeping the system clean in a dirty environment. It is an excellent idea to keep all your equipment covered when not in use, as this is likely to prolong its sonic life significantly. All chassis have vent holes through which heat is released, but these are also entry points for dust. When the component is turned off and cool, cover the vents.
Connections oxidize and become coated with smoke, cooking oils, furnace soot, and other airborne films. This very fine layer interferes with good surface contact, resulting in a degraded connection and in distortion. Connections can loosen over time, producing a connection that is constantly, invisibly, broken electrically, causing arcing, sonic degradation, and eventually probable damage. Disconnect and reconnect all cables and interconnects (all nonsoldered, noncrimped connectors) at least once every six months or so. Start with your cartridge pins, which must be very gently removed and reconnected, using a pair of small needle-nose pliers or tweezers, then proceed all through the system to the speakers. The friction of disconnecting and reinserting alone will somewhat clean the connecting surfaces and improve contact. Do not overlook the wall plugs. Plug and unplug several times to clean the prongs and be sure they provide a snug fit in the outlet. (Be sure to maintain plug polarity.)
Cramolin from Monster Cable will clean off this film. It should be used only in places where you can rub it off again vigorously, leaving behind an extremely thin protective layer. Cramolin Red is a cleaner and protector, the Blue a preserver; Red is the important one. When you’re using it on internal connections such as jacks, Monster recommends diluting it heavily with alcohol. Cramolin is generally a respected product. However, some feel that a Cramolin-treated connection sounds better than a dirty contact but less good than a clean one. Do not, in your enthusiasm, clean your tube pins with it—when the pins heat up, the Cramolin burns on. While the tube itself is easy enough to replace, the socket holes will also be caramelized with Cramolin and almost impossible to get clean again.
Tweek, sold by Sumiko, when applied to contacts, protects the metal surface. It also actually improves the “sound of the contact.” Apply it to metal only and keep it away from plastic.
In the case of jack connectors, you should rotate the jacks in their socket to abrade off any oxidation—this is so easy you should do it monthly. Be gentle—you do not want to stress the connection between wire and jack or break the wire.
All switches and knobs on your components should be rotated or flipped every few days to maintain friction-cleaned connections.
Periodically treat control knobs with a contact cleaner such as Chemtronics Kontact Restorer. Do NOT use WD-40, as much as this seems a logical choice—it has been known to destroy the mechanism. If the component is still under warranty, it may be wise not to clean the switches yourself, as removing the cover voids the warranty. Turn off and unplug the component at least half an hour before cleaning—capacitors store a charge that drains off only slowly after the unit has been turned off. Touch one that’s still charged when you’re also touching the chassis and it’ll drain off into you very quickly. While not lethal, this is definitely startling and to be avoided.
To clean the switches, be sure the component is unplugged, then remove the cover. The backside of the control panel should now be visible—if not, remove whatever is covering it. Spray all the controls with contact cleaner. Rotate and flip them back and forth rapidly to dislodge dirt and grease, then spray again. This spray is nonconductive and noncorrosive. It will cause no damage if not wiped off. Replace the cover before plugging the component back in.
The belt should be periodically checked and cleaned, and replaced every couple of years. Old belts tend to become stretched and can pick up airborne oils, altering the grip on the drive pulley and platter. First clean with alcohol, then dust with talc, cornstarch, or arrowroot (very effective) to give the belt a good grip.
Periodically recheck the table setup for levelness, spring adjustment, and the like. Use your level on table support and platter. Check that the tonearm board is still horizontal and parallel to the table’s surface. Give the platter a sharp push straight down in the center and watch for oscillations—if it bounces vertically, it’s fine; but if it oscillates sideways, the springs need to be set up again.
Check the cartridge setup. The stylus or the entire cartridge should be replaced about every 6 to 18 months. Under constant use, a cartridge—or at least the stylus assembly—should be replaced about every 1,000 hours, some say as often as every 500 hours. So if you play your records for a couple of hours every day, that’s over 700 hours by the end of a year. Listen for any sonic changes.
To try to determine wear by examining the stylus tip under a magnifying glass will reveal only gross problems, such as chips, which will already have caused damage to your records. A special high-magnification microscope is needed to see the early stages of wear before it causes damage: Therefore, it is wisest to schedule regular cartridge replacement.
In addition to stylus wear, it should be noted that cartridge compliance stiffens with age. Compliance is largely determined by the cantilever’s damping materials, which age through magnetic effects, mechanical wear, and chemistry. This process continues even when the cartridge is not being used, so cartridges do have a shelf life. This life span is harder to determine. Jim Boyk, a well-respected pianist, guiding light of Performance Recordings, avid audiophile, and audio consultant, recommends replacement every 18 months, regardless of actual use.
Tape Decks (antiquated format)
Each minute a cassette is playing, many millions of magnetized particles pass by the tape head. Some of these particles flake off on the head; the magnetic field on the tape also magnetizes the head. The pinch roller gets dirty and flaked with minute pieces of tape or dirt, with the result that the effective diameter of the pinch roller increases which - throws off the speed. The same applies to a dirty capstan. It is essential that these be kept clean and that the heads be demagnetized.
Head-cleaning cassettes are very convenient and effective to use, providing you clean the heads and transport frequently. If you haven’t cleaned them for a while, the oxides will be so built up that you’ll need to deep-clean the heads with special head-cleaning fluid or alcohol on cotton swabs. Also clean the pinch roller with alcohol, being sure not to drip any down into the machinery. Demagnetize the heads with a cassette de-gausser (demagnetizer). Always use clean, high-quality tapes unless you have absolutely no alternative. When you do have to use old or cheap tapes, the heads should be cleaned immediately after.
Even brand-new decks may have misaligned heads, perhaps knocked slightly askew during shipping. As the heads wear, alignment changes. It is a good idea to check head alignment every year, then either correct the azimuth yourself or get the machine serviced. A fairly crude but simple test for checking correct head alignment is to play a tape that was made on a properly set-up machine. (If you are uncertain about this last factor, use several different tapes that you at least believe were recorded on an aligned machine.) As you listen, periodically switch to mono. If the treble drops off in mono, or you hear a whoosh from frequency cancellation, chances are your heads need checking.
The other method is to play a special azimuth test tape and adjusts the head tilt until you obtain maximum output as indicated by an audio voltmeter. If your deck has VU meters that are mechanical rather than electronic and can therefore register fine differences in signal level, and if the meters read playback level, these can be used instead of a volt meter. If the azimuth alignment that gives maximum output to the left channel differs from that to the right channel, you will have to compromise between the two.
It is best to use a test tape that includes both a low-frequency tone around 5 kHz and a high-frequency tone around 12 to 15 kHz. First adjust azimuth using the 5-kHz tone and then fine-tune it with the higher tone. If you adjust on the basis of a high-frequency tone alone, it is possible to get false azimuth peaks that are lower than the true azimuth peak output, iii which event your heads will be misaligned.
In the case of separate recording and playback heads, align the playback head first. Then, to align the recording head, simultaneously record and play back a high-frequency tone and adjust the recording head for maximum output in playback.
There is effectively no maintenance you can perform on a tuner, other than keeping it clean. Keep it covered to protect against dust. Periodically clean the connections and treat the switches and knobs.
There is little maintenance you can perform yourself on CD players, aside from keeping them covered when not in use. You may not even be able to get access to the push-button switches to clean them periodically.
If you find you are suffering from more faulty discs than you used to, it may be worthwhile to have the machine checked for a dirty laser— especially if your player is a year old or more. This can be cleaned much the same way you clean a tape head—except, unfortunately, you cannot do it yourself as it is not placed where you have access to it.
The average life of a laser head is about 5,000 hours, according to Steve Harris of Marantz Audio. However, there have been a number of reports in the audio press about premature laser-beam failures, some after only weeks, others after a year or so, far less than the statistical lifespan of 5,000 hours. Replacement is not inexpensive.
The Amplification Stage
The amp fuse should be replaced regularly as it oxidizes and de grades sound, though subtly.
Tube amps will need periodical re-tubing and re-biasing. Roger Modjeski of Ram Tubes estimates average tube life at about 1,000 hours, at which point you get degradation of sound. So if you listen a couple of hours every evening, the tubes should be replaced every year and a half or so, to maintain optimum sound. Check also with the designer regarding tube life—some amps run their tubes closer to the limits of the tubes’ tolerances, which tends to shorten their lifespan. This can also make the unit’s sound particularly sensitive to what tubes are used. Keep a fresh set on hand. As you approach the estimated end of the first set’s sonic life, substitute the new set and listen for a difference. If you hear no improvement, return to the first set and get a little more work out of them.
You can check for tube aging by looking at the getter, the silver dome at the top of the tube. If you see a very faint whitish ring, this indicates that the getter has receded from its original position, which means it has been around for a while.
Tube quality varies substantially and tube sound will differ from one company to the next, and from one tube to the next. Experiment and/or follow the amp manufacturer’s recommendations. Many feel that Ram’s tubes are perhaps the most consistently good. Others report positive experiences with Gold Aero. Some good tubes have been coming out of China. Mesa Boogie, considered the Rolls-Royce of music amps, carries a 12AX7 that sounds very good and is consistent in quality. It is manufactured to the company’s specs by Sylvania.
Every time you replace a tube in an amp (not a preamp) you must re-bias the component. Set the bias and check it again after a few hours, then after a day, then again after a few days—bias can change as the tubes burn in. In between tube changes, bias should be checked periodically. Bias drift can cause the image to wander and overall sound to become degraded. Some tube equipment does not allow “user biasing,” requiring the unit to be returned to the manufacturer for both re-biasing and re-tubing. This is a real drawback, as you will be without your equipment for probably a minimum of ten days (also incurring the risk of shipping damage and the expense of shipping) while this very simple procedure is being carried out by others.
Speakers are fused as protection against being blown by excessive amp power, clipping, or other sudden surges in amp power or distortion. These fuses should be periodically replaced, as old ones may corrode and certainly oxidize. Use the same amperage. Do not use slow-blow fuses (unless this is specified by the manufacturer) as they may not react quickly enough to prevent all damage to the speakers.
Since the music signal must pass through the fuse, obviously this has some effect on the sound. The correct fuse will cause a subtle but not unimportant improvement in the clarity, detail, and imaging qualities of the sound. Some listeners replace the fuse altogether with a same- sized rod of solid silver from a jewelers’ supply house, hearing less signal degradation from the silver than a fuse. However, while the speakers may sound great, they are also now unprotected. Proceed at your own very real risk.
With dynamic speakers, it is also a good idea to retighten periodically the screws securing the drivers to the cabinet, as the constant vibration tends to loosen them.
If NOTHING works, relax. This is often the easiest situation to correct. Check to make sure everything is plugged in, that the outlets you have plugged into are live (test this by plugging in a lamp to see if it works), that no fuses or circuit breakers are blown. If a fuse keeps blowing, you have too much plugged into that line. Don’t try to get around the problem by replacing the fuse with a larger one; instead correct the problem by lessening the line’s load.
If just one component doesn’t work, check its fuse. This is usually at the back of the component, beside its AC power cord. Remove the fuse and see whether it has blown. Inside the glass tube capped with metal ends is a thin wire or bar of metal. If the wire is broken or the glass looks smoky, the fuse has blown. Replace it with an identical match for value (amperage) and type (slow-blow, fast-blow, or neither)—-take the fuse with you to the electronics store. If the replacement fuse blows too, take the component in for repair.
If the components light up but you have no sound, check the controls to be sure they’re not switched to “tuner” when you’re trying to play a record, or to “tape monitor” or “speakers off.” Be sure the volume control is not turned all the way down and that the balance control isn’t turned all the way to one side. Be sure the speaker connections are tight—if they’re not, turn the system off before securing them.
If you are getting strange noises, the first step is to determine the origin of the problem and then see whether you can fix it yourself or will have to take the component in for repair. First, try all the sources— turntable, tape deck, tuner, CD player. If the problem is common to all signal sources, then it must be in the speakers, preamp, or amp, the only components common to all sources. To find the specific component causing the problem, follow the same methods as for tracking down hum.
If you have no sound or distorted sound in both channels, the problem is probably in the amplification stage—the odds against both your speakers’ blowing at the same time are very high, unless you’ve been abusing them.
If the problem is in only one channel, say the right channel, then start downstream and work back toward the source. First check whether the problem is in the speakers by reversing the leads at the speaker. Take the right-channel lead and connect it to the left speaker, the left- channel lead to the right speaker. If the problem remains in the right speaker, then that speaker is the problem. If the distortion is now in the left, instead of the right, speaker, then the speaker cannot be the problem and the source is further upstream. Assuming the speakers are fine, restore the cables to their original positions.
Next find out if the problem is in the speaker cable by reversing the cables at the amp (turn the equipment off first). If the problem changes channels again, then restore the cables to their correct positions and move on to the next point upstream, the amp stage.
If you have a separate preamp and power amp, you can determine which has the problem by reversing the interconnect between them. If the problem changes channels, it’s in the preamp. If it doesn’t, it’s in the power amp.
The Turntable System
The turntable system is a very delicate instrument that must be carefully set up and maintained. Most problems are simply a matter of the table’s having drifted out of tune. (See pp. 230 and 280 for full details.) If the sound seems worse than it used to be, or if it is generally distorted and breaks up and “shatters during high-level passages, check for the following problems. First be sure the stylus is clean. Then check tracking force: Be sure it isn’t set so high that the stylus has receded up into the cartridge body. Too light a tracking weight also causes distortion. Use a stylus pressure gauge to reset the tracking weight according to the manufacturer’s specs—set it toward the maximum end if the cartridge was tracking too lightly. Check that the tonearm is properly balanced so that it “floats” when the tracking force is set to zero. Check the antiskate, especially if one channel sounds fuzzier than the other; try setting it a little lower than recommended. If your stylus is a year old, replace it. Worn styli are record erasers and the damage they do is irreversible. If you happen to be broke at the moment, get the Joe Grado $40 MTE +1 cartridge.
A sensitivity to groove skipping or jumping may indicate that the table is not level. Place a small level on the platter and adjust the table until it is truly horizontal. You can usually raise or lower one or more of the four corners of the table as needed by screwing in or slightly unscrewing the rubber feet.
Speed inconsistencies where there used to be none may indicate the need for a new belt on a belt-drive table. On direct-drive tables (of which the only audiophile-approved models start at over a grand), alter the speed/pitch control, or you may want to consider replacing the table if it is a mass-fi one.
Hum is often caused by a grounding wire that has come loose— check at the back of the table and the back of the preamp. Also check the cartridge leads for tightness and correct placement. Reverse the table’s line cord. Plug the power cord into the wall instead of the back of the preamp. Experiment with reversing the plug to determine correct plug polarity. Move your preamp a little farther away and to the right side of the table.
Rumble or a boomy sound suggests the table is suffering from acoustic feedback and should be moved farther from the speakers, and / or should be placed on a more solid support.
The tape heads and transport must be kept clean or the sound of your tapes will deteriorate. The heads must also be regularly demagnetized. If sound quality has been worsening, the first step is to clean and demagnetize the deck.
Tape squeal, flutter, or wavering speed is suggestive of a problem in the mechanism of the cassette tape itself. However, if this problem comes up consistently on a number of tapes, the problem may be in the deck, which should be serviced. Test for this problem using new commercially recorded tapes, since, if you use your home-recorded tapes, you cannot know if the problem is in the turntable you used to make the recording. Buy new tapes because the problem may be that all your tapes have just become old. Wow or flutter, providing you’re sure it’s not on your tapes, is a sign that the deck needs a belt replaced—this requires expert service.
Distortion and hissiness on home-recorded tapes suggests you may be using the wrong recording levels or tape bias. Check the instruction manual to set your deck properly for the kind of tape you’re using.
Dull high frequencies can mean several things: The heads may need demagnetization and the heads and transport cleaning; you may be incorrectly matching playback equalization to your tape; or if you make your own recordings, you may be using too high a bias setting.
The major problem with FM reception is multipath distortion, which is characterized by a nasty, variable noise. Tuners differ in their susceptibility to this problem but it can be largely alleviated by the antenna. Check that the antenna connections on the back of the tuner (or receiver) are correct and tight. Be sure no stray strands of wire are crossing the two terminals. Move the antenna around the room to try to find the best location. You should consider replacing an indoor dipole antenna (a twin-lead wire that forks in two), which is probably what came with your tuner, especially if old. There may be breaks in the wire.
If your component has a muting circuit—this treats a signal below a certain point as noise and cuts it off—it may also be cutting off the signal you want to hear. Switch out the muting circuit, though this may leave you with a noisy signal; or, if you can, adjust its level. Sometimes switching to a mono setting will help minimize distortion.
The Amplification Stage
The electronics are the least likely to go wrong and, if they do go wrong, the most likely to need professional repair. The control switches may need cleaning—dirty ones will produce static and sometimes an intermittent signal that you can hear over the speakers. Also, the connections may be faulty—check that all are clean and tight (see prev. section for switch and connection cleaning). With tube amps, when a tube begins to go, you will hear a rushing, hissing sound through the speakers. Always keep spare tubes on hand; replace one tube at a time until the problem clears up. An overall degradation of sound may indicate that it’s time for a complete tube change and rebiasing. With the exception of a few components, you can easily do this yourself. Read the instruction manual or contact the manufacturer.
Speakers can blow a fuse (in which case they won’t work), can blow a driver (you’ll lose all treble if the tweeter blows, all bass if the woofer goes), and can distort a signal. But they can’t generate a signal—if you hear a noise when there’s no music signal going through, the speaker is not the problem. Problems occurring in both speakers are probably caused further upstream—each speaker carries only one channel and for both speakers to become defective simultaneously is very unlikely. If both speakers are damaged, the origin of the problem is probably up the line. Track it down or it will recur and again damage the speakers you just got repaired. For example, blown tweeters probably mean your amp is overdosing them with high-frequency signals.
Defects that are specific to the speakers are generally mechanical sounding and intermittent. Uneven response, buzzing on low notes, and squealing on high ones are typical symptoms. Electrical-sounding and continuous problems such as humming or hissing are probably not speaker problems. (To track down their source, see above in this section.) In correct speaker phase can degrade the sound.
Room acoustics may be the problem. To check, physically ex change the speakers along with their cables: If the problem that seemed to be in the right speaker remains on the right side when the speakers are exchanged, then the problem is with the room. How ever, if the problem moves with the speaker, then it is either in the speaker itself or in that channel.
Hum and system noise can be one of the most frustrating and annoying gremlins to track down in your system. Otherwise placid souls have torn their systems apart to find its source. Hum has all the irritation of a mosquito’s buzz but worse, as it never stops. Hum, like a mos quito, should be vanquishable, the listener feels, and therefore sets out determined to vanquish rather than endure. Unfortunately, it can be maddeningly elusive.
There are innumerable sources from which stray electromagnetic fields can creep into the sound: Every connection point and every chassis has the ability to pick up the electromagnetic radiation that surrounds us. We hear it as 60-cycle hum (the same sound you hear from just about any motor, or a fluorescent light fixture’s ballast, or a defective streetlight).
A very loud hum or buzz is most likely from a loose ground wire. Be sure your system is correctly grounded. Milder hums may be the result of faulty interconnects or cables—heavy inflexible wiring can cause broken connections at plugs and jacks, as well as bro ken strands of wire inside the jacketing.
Here’s how to track down hum methodically, according to Roger Modjeski of Ram Tubes. When listening for hum, adjust the system’s volume to your “normal” listening level. The importance of listening at normal levels is that this replicates “real-world” circumstances. If you can hear hum at maximum volume, but never listen that loud, how much does it really matter that the hum is there? Though it’s nicer to be without it, it could take forever to track down such a small hum.
Checking the Turntable
Turn on’ the table motor, as this is often a source of hum. Cue up the arm over the platter to check if the motor’s magnetic field can in duce hum in the cartridge—a phenomenon you can depend on in the combination of an AR table and a Grado cartridge. Do a preliminary check to discover if the table is the source: Listen on other inputs—to a quiet section of an FM broadcast, to the pauses on a CD disc. If you listen to a cassette tape, don’t use a homemade one—you may have recorded hum onto it.
Better yet, disconnect the table and insert shorting plugs into the phono inputs at the preamp (where the tonearm cable would connect). What shorting plugs (available at Radio Shack) do is in effect to replace all the wire in the cartridge and arm with a very short length of wire. Able to take the table out of the system this way, you can tell if the hum is also out of the system, in which case the table is the source. If the hum remains unchanged, then the table is in the clear and the hum is further down the line.
If the table is the source, do the following: First check that the cartridge isn’t picking up hum from a nearby power cord or transformer. You can usually tell by moving the tone arm—if the hum changes, then you know the cartridge is picking it up. Move either the hum source or the table. If the hum doesn’t change as you move the arm, then check the connections: (1) Check that the ground wire is connected between table and amp. If it isn’t, connect it; if it is, disconnect it. (2) Reverse the power cord plug. Be sure it is plugged into a wall outlet, not the back of the amp. (3) If you use a moving coil cartridge, move the leads from the table to transformers or preamp as far away from any power cords as possible. If the hum doesn’t drop when you short out the input jacks, then you know the hum is not in the table but in the preamp or amp.
Checking the Amplification Stage
Turn the volume all the way down on the preamp. If the hum also goes down, then the preamp is the hum source. If the hum remains the same, proceed on to the power amp.
If you have established that the hum is in the preamp, check for loose wires—experiment with running a grounding wire from the chassis to a true ground (a cold water pipe, the grounding screw on a wall outlet). The preamp may need servicing.
Assuming the hum is not in the preamp, next short the inputs of the power amp with the amp hooked up to the speakers. You should be able to put your ear up to each speaker and hear almost total silence — and, from a foot away, true silence.
Though none of these steps may themselves cure the hum, they will help to track it down to a specific component.
Next: Recording Care and Preservation