Tape Guide (March 1977)

Treble Troubles

Q. When I record from records, 1 get almost perfect reproduction in playback with the source. But when I record off the air, the result is a dramatic loss of treble on playback. The tuner has a somewhat defective treble response, so when listening to the tuner 1 boost the treble to compensate. But the tape recordings from the tuner have much less treble than even the original signal.

-Granville Harper, San Francisco, Cal.

A. It may be that treble loss in the original FM signal and treble loss in the tape deck combine to produce a very noticeable loss to the ear, whereas treble loss in either the tuner or in the deck seem slight. To illustrate, a loss of 2 dB is hardly noticeable, whereas a loss of 4 dB is quite noticeable. Also, you may be saturating the tape at high frequencies which has the effect of reducing the treble to the rest of the audio range. If you are applying treble boost to the tuner signal before recording, this would increase the likelihood of tape saturation and treble reduction. You can check this by recording FM at lower levels.

Alligator Clip Alternative

Q. I want to feed the signal from my hi-fi into my tape deck, but my hi-fi only has jacks for either playback or microphone so I bought some alligator clips and hooked them into the speaker leads to record from either the radio or the turntable.. To do this I must turn the sound up very high, still the tape playback is very low, although clear. How can I make a proper hookup?

-Noah McDougal, Port Washington, N.Y.

A. You are obviously not getting enough signal voltage at your amplifier. output to the speaker. Probably you can get enough signal at the amplifier volume control, that is between the hot and ground terminals of the control. This is a fairly simple connection to make for a technician or an experienced audiophile, or alternatively, you can continue to take the signal from the amplifier output and feed it into one of those small pre amps that audio stores sell for tape playback, phono playback, and microphone amplification. You would use the microphone facility for flat response. However, such a hookup would probably not give you as flat and undistorted a signal as would be obtained at the volume control of your amplifier.

Demagnetization

Q. I have both a TEAC and a Sony tape deck. I have regularly demagnetized both machines but have never detected any audible difference in sound quality either before or after demagnetization, even though I have tried a number of demagnetizers.

What is the explanation about the need for demagnetization?

-James Sipkins, Northfield, Minn.

A. There are several factors that may have a bearing on your inability to hear differences before and after demagnetization. If your hearing acuity in the treble range drops off appreciably above 12,000 Hz, the treble loss due to magnetization may not have much impact, the quality of the tape deck as some units are better designed to resist magnetization than others by avoiding current surges, and the number of times a recorded tape is played since with repeated playings the treble response gradually deteriorates, thus slight magnetization might have a noticeable effect only after a considerable number of playings. To preserve response out to 20,000 Hz, it is generally agreed that magnetization should be kept to a minimum if a tape is to be played fairly often. Furthermore, demagnetization is a preventive measure, and one should demagnetize before significant harm can be done by magnetized heads and other surfaces. This preventive maintenance would also reduce the opportunity for noting differences.

Reel Shortage

Q. Is there any possibility in the near future that 10 1/2-in. reels of blank tape will be easier to purchase? I have a tape deck which takes 10 1/2-in. reels and it frustrates me not to be able to purchase such tape.

- James Sauerbier, Wash., D.C.

A. You are correct in pointing out the relative scarcity of 10 1/2-in. tape on the consumer level. However, it is available from the larger audio supply houses. If you query the catalog houses such as Lafayette, or discounters in your area such as Saxitone, you should have no trouble locating 10 1/2-in. tapes.

Head Replacement Snafu

Q. A number of years ago I purchased an Allied TD-1030 tape deck. 1 was able to record at fairly high volume without audible crosstalk, and after about 1,000 hours machine use I installed a $6.00 replacement head, but have had some trouble with it.

The crosstalk level is considerably higher than with the old head even though the azimuth alignment has been verified by a professional serviceman. Would I get appreciably better results by using a replacement head in the $25.00 range? What is the proper bias frequency?

-John Streby, Flint, Mich.

A. When one considers that high-quality tape heads cost as much as $50.00, $75.00, and $100.00 or more, it is difficult to expect much from one costing $6.00. Your problem might ...

(Source: Audio magazine, March 1977; Herman Burstein)

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