Tape Guide (Apr. 1982)

Terrible (Type) IIs

Q. My cassette deck records successfully when I use ferric oxide tape.

But when I use chromium--dioxide or cobalt--modified tapes, there is a 10 to 12 dB loss in the treble range with the switch in the CrO2 position.

-Steve Harris, Conway, Ark.

A. It appears that the problem does lie in your cassette deck inasmuch as there is no problem with ferric oxide tape. The problem could be due to excess bias and/or faulty equalization when the tape switch is in the chrome position. You will need the help of an authorized service shop and can get the names of such shops from your dealer or from the manufacturer.

Source, Tape, and Listen

Q. When monitoring a recording, are you listening to the sound already recorded, or are you listening to the sound a split second before it is recorded?

-Bob Hoffman, Worth, Ill.

A. If you are using a tape deck with three heads, which permits simultaneous recording and playback, in the monitor (or tape) position of the monitoring switch you are listening to the tape which has just been recorded. In the source position, you are listening to the signal which is about to be recorded.

Manual Aid

Q. I am having a problem obtaining the service manuals for my cassette deck and receiver, both made by the same company. 1 wrote to the firm a couple of months ago but received no response. Please help me.

-Daniel Pinero, Juncos, Puerto Rico

A. Unfortunately, there is no way in which I can be of direct help. I suggest that you write again, this time to the Service Manager, with a copy to Customer Relations and another copy to the president of the company, stating that you had no answer to your first request. Do not expect to get the manuals free. They could possibly cost $5.00 or more each.

Another possibility would be to try an authorized service shop. It is unlikely that it can sell you manuals, but the shop might be willing to inform you how to buy them, or it might be willing to order them for you, probably for a small fee.

GIGO?

Q. I have a chance to buy open-reel tape costing $1.00 for 1200 feet. It is cut down from 1/2-inch computer tape, and it has been erased. Is this a good buy?

- Tony Iacovelli, Framingham Ct., Mass.

A. The frequency response characteristics and bias requirements of computer tape usually differ from those of audio tape. If you use computer tape, it is possible, although not certain, that you will find performance inadequate in terms of frequency response and distortion.

Another problem concerns the accuracy of slitting. Accurate slitting requires very precise and expensive equipment. Improperly slit tape tends to raise problems. If the tape is too wide, it tends to stick in the tape guides; if it is too narrow, it tends to weave in the tape guides, resulting in variations in frequency response or output.

On the other hand, for a risk of only $1.00, you might try a reel.

Combined Heads

Q. My cassette deck has a combined record/playback head. Is my preamp's monitor switch of any use to me when recording?

-Joseph Cuifo, Utica, N.Y.

A. No. Such a switch is useful when using a tape deck with separate record and playback heads in order to compare the just-recorded signal with the source signal.

Mix Master

Q. My cassette deck has a line/ mike mixer. I would like to use this to mix the signals from two turntables when recording, one through the line inputs and the other through the mike inputs.

-Jean LeTourneau, St. Jean, P.Q., Canada

A. Unless you make fairly extensive modifications to the record electronics of your tape deck, you cannot use it to mix the signals taken directly from turntables that employ magnetic phono cartridges. What you require is an external mixer which can accept the cartridge signals and feed the combined signal to your line inputs.

The signal delivered by a magnetic phono cartridge requires bass boost and treble cut in order to achieve flat response. It also requires a substantial amount of amplification overall. If such a signal is fed to the mike input of your deck, it will receive the necessary amplification but not the necessary bass boost and treble cut. If it is fed to the line input, it will receive neither the required amplification nor the required equalization. A suitable external mixer can meet these requirements.

Bar Some

Q. In taping a disc of Also Sprach Zarathustra, my cassette deck produces distortion during the opening bars of the trumpets; the level setting causes only a few rare swings above 0 VU. The distortion consists of a fluttery kind of warbling, and it occurs with two high-quality tapes but not with a cheaper tape of the same brand. I do not get this distortion when taping with my open-reel deck. What is the problem?

-Fred Schmidt, Livonia, Mich.

A. It appears that the tape is being overloaded. The amount of signal that a tape can handle without noticeable distortion varies from one brand to another and from one type to another. Try a lower recording level, or stay with the particular tape which gives you best results.

Head Demagnetization

Q. How effective is a head demagnetizer, and how does the user know when the heads are demagnetized?

-William Dickerson, McChord AFB, Wash.

A. Head demagnetizers vary in strength, as may their effectiveness. A magnetometer, such as the one made by the R.B. Annis Co., Indianapolis, Ind., can measure residual magnetism in the heads (and in other metallic parts contacted by the tape, such as guides). From my experience with head demagnetizers and with the magnetometer, it appears difficult or impossible to reduce magnetization to absolute zero. Nevertheless, it may be important to periodically demagnetize the heads and other parts to the extent that is possible.

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

= = = =