By Craig Stark
Contributing Editor Stark checks out Phase Linear's Compact Disc player at the Winter CES.
Cold-Weather Blues
Q. Does it hurt to leave my cassettes out in the car during really cold weather? If I play them when they're cold they seem to drag severely.
TERRY MEYER
Miranpa, S.D.
A. I think you've answered your own question. Assuming that it's not near-frozen motor bearings on your car's cassette player that are causing the sluggish tape movement (test for this by playing a cassette warm from the house in the cold player), if a cassette shell has contracted sufficiently to impose a severe drag on the tape, your deck's drive system could easily stretch or even break the tape. If bringing your cassettes inside with you is not practical, you might experiment with Loran cassettes, which have Lexan shells that are said to hold their shape even in temperature extremes, although most premium-quality cassettes can withstand ordinary cold and heat just fine. Cassettes with Lexan shells might be a good choice too if you find it necessary to park for any length of time under the hot summer sun.
Trading Treble Loss
Q.
A friend and I both own high-quality three-head cassette decks, and we us, the same type and brand of tape with the same bias and equalization settings.
When we play each other's (non-Dolbyized) recordings, however, both of us encounter large treble losses that do not occur when we play the tapes on our own machines.
Does one (or both) of our machines need its playback-head azimuth adjusted, and, if so, how is this done?
MANNY GOMEZ, JR.
Brooklyn, N.Y.
A. Your diagnosis is correct, and let's hope that only one of the two decks is out of alignment, because after you fix a misaligned deck all the tapes recorded on it before the adjustment will sound just as dull when you use it to play them as your tapes now do played on your friend's machine! To avoid losing use of these tapes permanently, first determine if you and your friend have one properly aligned deck between you.
(You can do this by playing a high-quality prerecorded cassette on both machines.
While prerecorded cassettes are not always perfect, the better ones are close enough to give you an indication of misalignment by sounding noticeably dull.) If one of your machines is correctly aligned, before you fix the other, use it to dub all of the recordings made on it. Play them on the mis aligned deck and record on the correctly aligned one; after being fixed, the first deck will play back the dubs without treble loss.
(Since dubbing unavoidably increases hiss, I recommend using Dolby when you make the copies and in playing them back.) As for how to make the necessary adjustment-frankly, azimuth realignment is not the kind of thing you should attempt on your own unless you have had some training and experience in this area. A competent repair shop or dealer will have both the necessary instruments and the experience required. If you insist on doing it yourself, however, you'll need the following: a calibrated playback-alignment tape (Nortronics, Teac, or TDK versions may be available at some audio stores), a sensitive a.c. volt meter (0.1-volt full-scale is marginally adequate; 0.03-volt may be necessary with some decks), and a nonmagnetic screwdriver to fit the azimuth-alignment screw on the problem deck (this screw is normally located immediately next to the side of the head and is usually spring-loaded). If you can also get an oscilloscope it will make the job easier.
Play the calibrated tape, whose azimuth tone(s) will generally lie between 8 and 12 kHz (the higher the better once you're close to final adjustment), and monitor the out put from one channel on the voltmeter.
(You can monitor the tape itself on the other channel through your regular system.) Turn the azimuth screw slightly one way, then the other, to obtain the maximum reading. Then change channels and re-peak the meter-they'll be close, but probably not identical. Split the difference until you get the best compromise setting for maximum output at the highest frequency from both channels. If you have an oscilloscope, you can connect the left- and right-channel outputs from the deck to the X and Y inputs of the scope (use the X-Y position instead of a horizontal sweep). Adjust the azimuth screw for a diagonal line (from upper right to lower left) or as narrow an ellipse as possible, checking other frequencies on the tape as well as the azimuth tones. A diagonal line indicates zero phase shift between the two channels.
The "Best" Tapes?
Q. In your tape-deck reviews I've noticed the same "premium" tapes noted again and again as having given the best performance on the recorder. Why won't you and STEREO REVIEW come right out and say, "These are the best tapes on the market"? Better yet, why not test the decks with the less-expensive tapes that many of your readers use and can afford? And does anyone need metal tape at twice the price?
CARL THOMAS Bloomfield, N.J.
A In a sense, one of your questions almost answers another: for you the "premium" tapes (including metal) that I normally use are not the "best" tapes because their technical advantages aren't worth their higher price. That's one reason we don't say "Brand So-and-So" is the best on the market. Besides, if you look closely, you'll see that I do use a fairly wide number of tapes--and the brands change from time to time, not only with the particular machine being tested but as I receive upgraded formulations.
The main reason I use premium-grade tapes rather than more attractively priced ones is that I want to make sure--so far as I can-that I am testing what the deck is capable of doing. I could use a cheaper tape that might measure almost as well, but then I could never be sure what the limits of the machine were, and I'm trying to test decks, not tapes. In other words, while two decks might give identical results with a second-or third-line tape, one of them might do a far better job with a top-line tape. Without using the best tapes available, I couldn't be sure that I wasn't doing an injustice to the better deck.
Replacement Tape Boxes
Q. I have about fifty 7-inch open-reel tapes whose boxes have been badly damaged, though the tapes themselves are fine. Is there anywhere I can get the right size boxes for protection, labeling, etc.? Some of the tapes are very rare.
JANICE. L. CROZETTI
Prescott, Ariz.
A. While a number of parts stores (Radio Shack, for instance) will sell boxed empty reels, I haven't found any source for just the boxes. My suggestion is to call a professional recording studio in your area, since they undoubtedly do a lot of custom duplicating and may have a supply of boxes on hand. Also, watch the classified ad pages of this and other audio magazines. For reels where maximum protection is needed you can get metal 8-mm movie-film cans in the right size from a photo dealer.
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