Tape Guide (Q and A) (Jan. 1972)

Separating Transport and Amp

Q. I was wondering if I could take the transport of my tape recorder out of its case and make the wires to the amplifiers longer. Or would I get a distortion? I was planning to build the tape recorder into the wall and to put the tape preamps in a desk.

When recording, how high should the VU pointer go?

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

A. I suspect that if you change the existing wiring arrangement between your tape transport and the tape amplifiers you may run into problems of hum pickup and treble loss.

If your tape machine's VU meter is properly calibrated, you should ordinarily set recording level so that the pointer does not exceed 0 VU. But this is only a general statement. Depending on the nature of the sound source, you may find that sometimes there is no audible increase in distortion if you allow the pointer to swing as high as 3 VU; and at other times you may find it necessary to keep the meter down to -3 VU or even lower in order to keep distortion from being objectionable.

Thus if you were recording a live guitar, with its strong transients, you might have to keep the pointer down to about -10 VU. Experience and judgment must be brought to bear.

Sound On, With, and Over

Q. I am confused by the terms "sound-on-sound," "sound-with-sound," and "sound-over-sound" Could you please explain these terms.

-J. R. San Filipo, APO San Francisco.

A. Sound-on-sound means that you can synchronize two or more sounds on the same track. To illustrate, record track 1; play track 1 and at the same time record the track 1 sound along with a new sound on track 3; play track 3 and record the track 3 sound along with a new sound on track 1; etc. Sound-with-sound permits you to synchronize two sounds on two tracks (not on the same track). Sound-over-sound permits you to record on the same track as a previous recording, but without erasing the previous recording; this is analogous to a double exposure in the case of a camera.

Speed Vs. Quality

Q. I am trying to decide between two tape recorders, one of which operates at 15 and 7 1/2 ips, and the other at 7 1/2 and 3 3/4 ips. I understand that the faster the tape speed, the better is the tape recording. Your advice would be appreciated.

- Ronald Brown, Vietnam.

A. You are correct that the faster the tape speed, the better the recording.

However, in today's state of the art, the high quality tape machine can achieve results at 7 1/2 ips that are virtually indistinguishable from those at 15 ips. In fact, a few can even do so at 3 3/4 ips.

For home recording there no longer seems to be much purpose in operating at 15 ips with a really good tape machine. On the other hand, for professional purposes, where a tape may be copied several times, with some deterioration in quality with each copy, the slight advantage of 15 ips operation appears worthwhile.

Improving Treble Response

Q. I like my TEAC A6010, except for its poor treble response at 3 ¾ ips. At 12 KHz, response is about 10 db down at this speed. What can be done to improve the treble performance at 3 3/4 ips?

- Lawrence E. Root, Sacramento, Calif.

A. Improving the treble response of your tape machine at 3 3/4 ips may involve one or more of the following measures: (1) installing a playback head with a narrower gap; (2) reducing bias current at 3 3/4 ips; (3) introducing additional treble boost in recording; (4) adding more treble boost in playback. Which of these measures is required and how much depends upon the characteristics and circuitry of your machine. Also, some improvement may be obtained through choice of tape.

Splitting Half-Inch Tape

Q. I am interested in splitting half-inch tape. Is width extremely critical? What are the width tolerances?

-Paul A. Smith, Jr., APO San Francisco.

A. So-called 1/4-inch tape actually has a standard width of 0.246 inch with a plus and minus tolerance of 0.002 inch.

Exceeding this tolerance may well raise problems of tape skewing or sticking in the tape guides.

(Audio magazine, Jan. 1972; Herman Burstein)

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