TAPE GUIDE (Dec. 1985)

Slow Stop

Q. I am happy with my cassette deck except for one peculiarity. When the end of the tape is reached in fast wind mode, the tape drive does not stop for several seconds. This period is accompanied by a moderate amount of squeaking from the deck. I have written to the manufacturer to ask about this, but they did not reply. Is this sound normal? If not, should I have the deck repaired?

-Craig Steinfeld, Silver Spring, Md.

A. I have found that cassette decks differ in the alacrity with which they respond to tape run-out. Some will respond promptly in normal operating mode but less so in fast wind, while others do the opposite, and still others respond promptly in both modes or not at all. Although I cannot say that the behavior of your deck is "normal" in the sense of operating as the manufacturer intended, it is within the range of common experience.

If a very few seconds pass before the transport stops, it is likely that no harm is being done. If the interval is substantial or getting longer, it is probably wise to take your deck to a competent service shop for repair.

Cassettes vs. CDs

Q. Is it worthwhile to continue in vesting in cassette tapes, considering that CDs are beginning to become fairly inexpensive and have higher sound quality?

-Brian Barth, Cambridge. Mass.

A. Presumably, you refer to investing in prerecorded cassettes. While the CD format offers superior frequency response, signal-to-noise ratio, distortion and motional stability as corn pared to cassettes, not all CDs live up to the promise of the format. And there are people--albeit a minority--who hold analog recording in higher esteem than digital, claiming that the latter has sonic defects which present measurement techniques do not show.

The top-quality cassette decks achieve very fine performance: Frequency response is essentially flat from about 30 Hz to 20 kHz. Distortion is less than what is usually audible on program material. Signal-to-noise ratio can be as high as 75 to 80 dB with Dolby C NR and about 85 to 90 dB with dbx NR; once S/N gets to about 75 dB, further improvements tend to make little perceptible difference, unless one plays at thundering levels. However, tape's motional stability (speed accuracy, flutter, etc.) is not as good as what is achieved by CDs.

Listen to both formats at their best and compare. But also compare their relative utility to you. If you already have a portable and/or car cassette player, and you decide to switch to CDs, you could get by with just a portable OD player (which can be used in the home and car, with suitable adaptors) but will probably want home and in-dash CD players, too. (Editor's Note: You might consider, in that case, buying CDs and dubbing them to cassette for portable and mobile use. With good tape, a good deck and an NR system such as Dolby C or dbx, the results can be impressive. –I.B.)

Swivel-Head Azimuth

Q. In shopping for a cassette deck, I visited a dealer who was intent on impressing me with the problem of maintaining azimuth alignment of the swivel heads in the current crop of reversible machines. Is this just sales talk?

-Coy L. Lay. Washington, D.C.

A. Maintaining correct azimuth alignment of the tape heads is crucial in order to preserve high-frequency response. To preserve response out to 20 kHz or so, azimuth must be maintained to within about 6 minutes of 1° of arc, and hence, there is very little room for error. It is easier to maintain precise azimuth alignment with fixed heads than with swivel ones, so what you were told is not mere "sales talk." On the other hand, tape-deck technology keeps improving, and the accuracy of swivel-head azimuth keeps getting better. You may want to read my article, "How Important Is Tape Azimuth?", in the September 1984 issue, for a more thorough explanation.

Cassette Longevity

Q. As my cassettes get older, it seems that their sound quality deteriorates. Is longevity affected by the number of times the tape has been played, the age of the cassette, or the type of tape?

-Brian Barth, Cambridge, Mass.

A. Tape quality is one of the chief factors in maintaining good sound re production over a long period of time.

A high-quality cassette is capable of 500 or more passes before deterioration sets in. Storage conditions are another factor; one should avoid excessive heat or cold, as well as humidity extremes. Also, some decks do handle tapes more gently than others.

Taping 78-rpm Records

Q. I am a Frank Sinatra buff. There are 150 or so Sinatra recordings which were issued only on 78-rpm shellacs between 1939 and 1949, and I want to dub them onto open-reel tape. I have a general idea of what is involved but need some guidance in terms of equipment, choice of styli, and basic techniques. Would you suggest the use of a transient-noise-reduction system? I have an SAE 5000A impulse-noise reducer, which I thought would help remove some of the ticks and pops in the old shellacs.

-Charles Granata; Bloomfield, N.J.

A. Yes, an impulse-noise reducer should be helpful. In addition, provided the two are not incompatible, a dynamic noise reducer could cut down on hiss and similar noise; the Burwen DNF 1201A has a switch position specifically calibrated for 78s, and the Packburn 123 has elaborate facilities for coping with 78s.

Correct equalization-precisely complementing the bass boost and treble cut used in making a recording--is another problem. The standard RIAA equalization used for all of to day's records does not match the equalizations used for 78-rpm records (which varied with the maker and the year), but it is the only equalization position available on the phono stages of most modern amplifiers and preamps. (The Onkyo P-3030 pre-amplifier is the only modern preamp I know of with both RIAA and 78-rpm phono equalization settings.) The main difficulty is excessive treble cut.

While tone controls can often be used to touch up equalization for play back, they usually do not affect a re cording because they are wired after the tape output jacks. Better results can be obtained by using an equalizer between your system and the tape deck. The Esoteric Sound Re-Equalizer (Audio, November 1985) is specifically designed for this use.

You will definitely need a different stylus for playing 78s. Shure, Audio Technica, Pickering, Stanton and per haps other cartridge makers offer various styli designed for the purpose; Shure even offers a hyper-elliptical version. Check your cartridge's manufacturer to see what's available, since few stores will carry these items in stock.

Because old record groove widths and shapes also varied, some companies specializing in items for collectors offer a variety of special styli for records which require them.

Search and Wear

Q. I have heard that using automatic search on a tape deck causes extra head wear. Is this correct?

-Dave Hoover; Iowa City, Iowa

A. In some decks, the tape is in contact with the head during automatic search, and this will cause extra head wear. In others, the tape is held a very small distance away from the heads, so no head wear will occur. In any event, most heads in use today last for a very long time-something like 20,000 to 200,000 hours of use-so automatic search (a feature found on the majority of tape decks) is probably a minor factor in reducing head life.

Demagnetization Alternatives

Q. I use a demagnetization cassette for my car deck and would also like to use it for my home deck, since it demagnetizes the capstan as well as the heads. My home deck has automatic demagnetization. Would the cassette demagnetizer harm it or be unnecessary?

-David E. Jones; Mt. Tabor, N.J.

A. Use of a demagnetizer, either a cassette or probe type, will do no harm if instructions are carefully followed. Even though your home deck has an automatic demagnetizing circuit, this would not demagnetize the capstan, so the use of an external demagnetizer is a good idea.

(Source: Audio magazine, Dec. 1985, HERMAN BURSTEIN)

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