Tape Guide (Apr. 1981)

Make an Educated Degausser

Q. I plan to buy a degausser, one end of which is intended for demagnetizing tape heads, and the other end for use as a bulk eraser. I have read that a bulk eraser may possibly damage tape heads and VU meters. Is this a safe tool to use for demagnetization?

-Maurice Zeff; Oakland, Calif.

A. The degausser will not harm your heads, assuming you use the end in tended for demagnetizing them. And I trust you have no intention of putting the bulk erasing end smack against the meters. Do not attempt to bulk erase tape while it is still on the deck, because you will risk bringing the bulk eraser dangerously close to the heads and meters.

Preamp Power

Q. The line input of my tape deck is too low for recording from my phono graph. Therefore, I have taped through the mike input. The sound that comes out is clean, but I am getting no bass, only the highs. Can you tell me what to do?

- Jerry Ubels; New Westminster, B.C., Canada.

A. The output of a magnetic phono cartridge requires considerable bass boost (in accordance with the RIAA standard), as well as overall amplification. Thus if you feed the cartridge out put directly into the mike input of a tape machine, you are not going to get the required bass boost. Probably the easiest solution would be to buy one of the inexpensive small preamps, for about $25.00 to $50.00, that are sold in audio stores. The express purpose of these preamps is to supply the equalization needed for signals from magnetic cartridges and tape heads.

What Does This Loss Signal?

Q. My problem is a gradual loss of signal on my tapes. The signal seems to stabilize at a low level, but sometimes this signal level is farther down in some spots, giving an up and down effect. If I replay these tapes, the variation of the signal level may not recur or may not be as noticeable as before. Is the cause the tape or the recorder?

- Terrell Cook; Spartanburg, S.C.

A. Your problem is not a common one. Some tape formulations are more susceptible to loss of recorded signal than others, but usually this phenomenon is confined to the treble range. How ever, you might try different brands of tape to see if you can eliminate the problem.

Magnetized heads and dirty heads, particularly the latter, can account for your problem. Dirt causes separation be tween the tape and the head, resulting in reduced response, although, again, especially at high frequencies. Magnetized heads or other magnetized objects making contact with the tape can cause loss of signal, so careful cleaning and de magnetization are recommended. Some tapes shed more oxide than do others, presenting more of a problem in maintaining good tape-to-head contact.

Therefore, certain brands of tape may cause more signal loss. Finally, there may be something wrong with the tape guides or other elements in the tape path so that the tape is skewing and failing to make constant firm contact with the heads.

Erase Now, Pay Later

Q. After dismantling an old portable electric generator, I discovered that the magnet was powerful enough to fully erase my tape reels. Can I continue to use this method in place of a commercially advertised bulk eraser, and how will it affect my tape recorder?

- Ray Gilbert; Baltimore, Md.

A. If yours is a permanent magnet, do not use it to erase tapes. Such a magnet will leave appreciable noise on the tapes. If it is an a.c. magnet, you can use it to erase tapes, but do not bring it in the vicinity of the tape deck, for it might do harm to the heads or meters.

The Agony of Delete

Q. I frequently make cassette copies of my phono discs, and I have noticed that when I attempt a simultaneous play back to make an A-B comparison, the tape gradually falls behind the disc. Is this is an indication of defective equipment?

-R.A. Stephan; Carmel, Calif.

A. In the present state of the art, moderate price cassette decks do not maintain as constant a speed as do record players. So I would say your experience is typical.

(Adapted from: Audio magazine, Apr. 1981; Herman Burstein )

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