Tape Guide (Q and A) (Jan. 1973)

Sluggish Take-Up II

The September issue of AUDIO contains a letter from Mr. Ellison concerning sluggish take-up on a Revox tape recorder. I wonder if the problem is not with the take-up motor itself but with the tape guides.

On the Revox the tape guides are cylinders with chrome end plates. It seems to be very easy for minute particles of tape to catch between the cylinder and the end plate thus slightly reduce the width of the channel for the tape. This makes the tape drag on the guide causing very poor take-up.

This cure is to take apart and clean the offending guide, a straightforward operation, and then to use only tape which does not shed pieces of oxide.

-G. W. Waters Providence, R.I.

Distortion on Old Recordings

Q. During the early 1950's I had a Webcor tape recorder and frequently taped broadcasts of the Metropolitan Opera, Toscanini, and others, which I cherished. The recordings were excellent, at least at that time. I sold the Webcor in 1956 but kept the tapes. I did not purchase another recorder until 1968, at which time I bought two (Sony 666-D and 560-D), along with a complete component system. I could hardly wait until I could play my tapes again.

But what a shock to discover that every one was distorted. And I noticed that as I attempted to play them the needles of the VU meters stayed at maximum level. Can you explain why this happened, when I am certain that when I made the recordings I did not overload the recording?

-Richard T. Koory, Arlington, Va.

A. Have you tried playing your old tapes on machines other than your Sony ones? If they still sound distorted, this would absolve the Sony's and place the fault in the tapes.

Possibly, distortion in your old sound system may have masked the tape distortion. Another possibility is that winding stresses may have physically distorted the tapes while they were standing unused for a dozen years. If this is so, the situation might be helped by winding and rewinding the tape several times before using it, thereby relieving tape stress. Still another possibility is that your new tape recorders and your new audio system are much more revealing of tape distortion than was your old Webcor; this could be in part because of the better high frequency response of your new components.

If your tapes sound satisfactory when played on another tape machine, then the fault is in your tape machine. In other words, the high level on your tapes may be overloading your machine.

Headphones

Q. Is there a set of stereo headphones which have a water-filled pad which conducts the sound to your ears. I have heard of such earphones, and that they produce exceptional sound.

Please tell me whether such earphones exist and who makes them.

-Benjamin Noval, APO San Francisco, Calif.

A. Stereo headphones with liquid-filled cushions are made by Sharpe Instruments, Division of Scintrex, Inc., Amherst Industrial Park, Tonawanda ( Buffalo), N.Y. 14150.

Tape Storage

Q. A question regarding storage of recorded magnetic tapes: It is suggested that they be stored in metal cans.

Surely this means cans of magnetic metal, steel, or sheet iron. I suppose a cabinet lined with sheet iron would do as well and avoid handling all those cans. A letter some time ago in AUDIO (November 1969) suggests that our homes are vast collections of bulk tape erasers. Your thoughts would be appreciated.

-F. A. Fetvedt, Fergus Falls, Minn.

A. I think that the danger of erasing tape from home a.c. sources (motors, TV sets, power lines, etc.) tends to be exaggerated. I believe that a metal can, or a cabinet lined with metal (iron or steel) of similar thickness to the can, will provide adequate protection. To check on the degree of danger, I have done the following.

I have taken a tape containing substantial high frequency material (these frequencies are the most susceptible to erasure) and brought it within less than a foot of a very powerful bulk eraser, and then played it. I could detect no change in the audio content of the tape.

(Audio magazine, Jan. 1973; Herman Burstein)

= = = =