Tape Guide (Nov. 1982)

Loose Packing

Q. I have a brand new high-quality open-reel deck. After fast winding, the tape seems to be loosely packed and to have a static charge. Do you think that the static charge is causing the loose pack? If not, what do you think is the cause?

-Edgar Duskin Jr., APO, N.Y.

A. Loose winding is probably due to insufficient back tension by the supply reel. I don't know whether static charges might aggravate the problem.

It would be best for you to contact an authorized service shop to remedy the problem, which may require only a minor adjustment. In the meantime I suggest that you not rewind your tapes after playing them. This will at least avoid long-term storage with a loose pack.

Not So Fast

Q. A friend of mine told me that it isn't a good idea to wind or rewind a tape at high speed unless I play it back immediately at normal speed.

Does this make sense?

-Evan Studinski, Loyal, Wisc.

A. Yes. If a tape is to be played within a few days, it probably doesn't do any harm to put it through fast forward or fast rewind before storage. But if it will be weeks or months before replay, it is wisest to operate the tape at normal speed before storage. Otherwise the tape may acquire a "set" corresponding to the strains of high-speed wind, causing distortion. The extent to which this happens depends on the particular tape deck. The more smoothly a deck winds the tape, the less likely it is that the tape will be deformed.

Quality Means Money

Q. With reference to professional open-reel tape decks versus the best of home open-reel decks, is the main reason professional machines are so much more expensive the fact that they have features which the home machines lack? Or is it that the professional machines are of higher quality?

-Michael Levy, Santa Monica, Calif.

A. The basic reasons for the high cost of professional tape machines lie in quality of performance and, perhaps more important, durability. To an extent, additional features also play a part. A professional deck may be working eight or more hours a day, day in and day out, and must therefore be relatively immune to breakdowns. It may be easy to align and to service. It must be convenient and flexible in operation (for example, editing must be facilitated by appropriate features that enable the user to locate the exact spot where the tape is to be edited). In terms of performance quality, a professional unit is constructed to have very low wow and flutter, very little noise, very low distortion, and excellent response-although in these respects it may be substantially rivaled by topnotch home decks. Controls for alignment-bias, equalization, record level, record indicator calibration, etc., must be readily accessible and easy to use. The bias oscillator must have extremely low distortion and excellent stability in order to minimize noise and avoid significant variation in frequency response. All of this substantially boosts the price tag.

Choosing Heads

Q. What is your opinion about the difference, in terms of frequency of response and distortion, between ferrite and permalloy heads in cassette decks?

-Larry Sonnenberg Jr., Dayton, Ohio

A. When ferrite heads first appeared, they had a very substantial advantage over permalloy heads in terms of life, lasting something like 10 times as long or more-which comes out to 20,000 hours of use or longer.

On the other hand, they were more subject to distortion, and it was harder to produce a straight, narrow gap--straight for accurate recording, and straight and narrow for good high-frequency response in playback. Therefore, a number of manufacturers of high-quality decks declined to use ferrite heads.

But with time, improvements in ferrite heads were achieved, making them suitable at least for erasure and recording. Thus, some deck manufacturers used a combination of ferrite and permalloy heads. New varieties of permalloy heads, such as hard perm alloy, were developed, increasing head life substantially. (Parenthetically, other high-quality types of heads, such as Sendust, were introduced.) It is difficult to say for certain whether you are better off with ferrite or some other type of head. It is possible that the best ferrite is better than an inferior permalloy. However, if I had to choose, I would be inclined to choose non-ferrite for playback and would toss a coin with respect to type of erase and record heads. In a field where things change very rapidly, I might be correct at the moment I write this and wrong by the time it appears in print.

Collectors' Item?

Q. I have a Model 4 Revere-Wollensak automatic cassette deck, which I bought in 1965. I am having difficulty locating prerecorded tapes that play properly on it, and I am unable to get it serviced by the manufacturer. I wonder if I should keep or sell it. Could it be a collectors' item?

-E. J. Carco, Malden, Mass.

A. You probably do have a collectors' item. The Model 4 used a special, single-hub cassette, whose tape fed to a take-up reel inside the deck during play, and then was rewound automatically. Tape speed was the same 1 7/8 ips as today's dual-hub "compact cassettes," and tape width was about the same; those were the only similarities.

Production of blank and prerecorded tapes ceased years ago. Service, however, may still be available. Contact Authorized Factory Service, at 97 Reade St., New York, N.Y. 10013. They say they can get some parts, and may be able to help you.

Finding a collector interested in buying it may not be easy. Orion Publishing ( 1012 Pacific St., Suite A-1, San Luis Obispo, Cal. 93401) issues a directory of audio equipment selling prices, but it may be more oriented towards normal used values than to value as an antique. Perhaps some of our readers can help?

Reel Mates

Q. I purchased a 7-in. metal reel for use as the take-up reel with my open reel deck. A tag attached to the reel says to be "sure to use exactly the same type of reel for supply and take up." All of my recorded tapes are on plastic reels. Does it really make any difference whether one reel is plastic and the other metal?

-Frank Fabian, San Francisco, Calif.

A. Generally, it is safest to use the same kind of reel, although not necessarily of the same make, for supply and take-up in order to assure proper tape tension and smooth operation when recording or playing back. This is especially true for the large-hub reels often used for prerecorded tapes. However, some decks are more tolerant than others with respect to a difference in reels. Yours may or may not be one of the latter. It is best to query the deck manufacturer on this.

Blocked Signals

Q. I bought a half-speed mastered phono disc and recorded it on cassette via a dbx noise-reduction unit and an 801 Omnisonic Imager. After playing back the cassette, the deck's left channel suddenly stopped working. I don't think there is anything wrong with the deck because it satisfactorily plays recordings made from conventional discs via the dbx and Imager. Why do I have trouble only with discs made from half-speed masters?

-Saul Andrade, Prospect Heights, Ill.

A. I haven't previously encountered your unusual problem. Are you sure that your cassette deck's left channel quits only when playing cassettes dubbed from an HSM (half-speed mastered) disc? Have you repeated the procedure enough times to rule out coincidence?

If it isn't a matter of coincidence, possibly there are frequencies on the HSM disc, occurring at sufficiently high amplitude that present a problem to your deck after you have dubbed them on tape. Sometimes, high signal levels at certain frequencies can drive the deck electronics into "blocking," so that for a period of time the electronics will not pass audio signals, although eventually the electronics recover. Try playing your HSM tapes on another deck, and if the tape causes no problems there, it would seem that your own deck requires service. The frequencies causing trouble may not be due to the HSM process itself but may arise from record warp.

(adapted from Audio magazine, Nov. 1982; HERMAN BURSTEIN)

= = = =