TAPE GUIDE (May 1984)

Feedthrough

Q. I own an integrated amplifier, separate tuner, cassette deck, and graphic equalizer. I have found that I can record from the tuner to the deck by turning on only the deck and tuner.

Can you please tell me how this works with the tuner connected directly to the amplifier and yet without the amplifier turned on? The deck is connected to the equalizer, and this doesn't have to be turned on either.

Also, does a cassette deck have its own preamp, so that no matter how fine an amplifier one has, it does not affect the recording quality?

-Mrs. W. J. Place, Winsted, Conn.

A. In the case of your integrated amplifier, it appears that high-level inputs, such as for a tuner, are fed directly to the tape-output jack via the selector switch; hence, the amplifier need not be on. In the case of your equalizer, it appears that when the unit is off, the incoming signal is fed straight through to the output.

Yes, a tape deck has its own recording amplifier. This supplies recording equalization (mainly treble boost, to overcome recording losses), a bias signal (that minimizes distortion and maximizes the signal level recorded on the tape), and amplification.

Azimuth in Reversing Decks

Q. I plan to buy a cassette deck and am considering one that reverses.

However, I've been told that if high-fidelity performance is important, I should forget about reversing decks because they entail a compromise of audio performance in exchange for the convenience of reverse operation. I was told that azimuth alignment is compromised, resulting in inferior treble response in one direction of operation or both. Is there much truth in this?

-Freeman Matthews, Columbus, Ohio

A. Yes, there is truth in this. Because the tape tends to skew differently in each direction (that is, when running left to right as compared with running from right to left), azimuth alignment may have to be a compromise between the best alignments for each direction. However, solutions have been worked out. Some decks rotate the heads 180° to record and play the tape in reverse, and provide a separate azimuth adjustment, often in the form of a set screw, for each direction.

One manufacturer (Nakamichi) makes a deck whose transport operates in only one direction, but records and plays in both directions by flipping the cassette over in the way one flips the page of a book-that is, like manually turning the cassette over.

Why So Expensive?

Q. I'm interested in buying a portable cassette deck both for home use and for live field recording, but the models that have the features I want are so expensive. Why do these portables cost so much?

-Paul Rubin, Berkeley, Cal.

A. Good portable decks tend to be on the expensive side because they are made to quite exacting specifications to achieve high performance under often difficult conditions. Further, they are made for a rather limited market, so each unit has to bear a high share of the model's design and development cost.

Demagnetization Again

Q. What type of demagnetizer do you recommend? I feel this is a rather risky business because, if not done properly, it can permanently magnetize the heads. An authorized technician told me not to demagnetize more than every six months.

-Thomas Eltrup, Elsmere, Ky.

A. A relatively powerful hand-held demagnetizer is usually considered best, but if the heads are difficult to reach, a demagnetizer contained in a cassette can be used. The heads can be magnetized if the degausser is shut off while in contact with, or in very close proximity to, the heads; otherwise, there is no danger. Depending on the type of material used for the heads and on the electronic circuitry employed, heads may need only occasional degaussing or possibly none at all. The usual advice is to degauss after every 8 to 16 hours of use, but the best thing is to follow the advice of the deck manufacturer, usually given in the instruction manual.

(Source: Audio magazine, May 1984, HERMAN BURSTEIN)

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