SIGNALS & NOISE (Letters to Editor) (Feb. 1987)

Packburn Switcher: A Clarification

Dear Editor:

We were grateful to read in the November 1986 issue of Audio of Robert Parker's use of the Packburn Audio Noise Suppressor ("London Letter" by Donald Aldous). But we would like to take this opportunity to add that the Switcher, which is one of three noise-reduction processors incorporated in the Audio Noise Suppressor, is a bit more sophisticated in its operation than Mr. Aldous' description.

Actually, he describes the operation of our first Switcher. But that was shortly superseded by a three-way Switcher which, in its rest position, reproduces the vector sum of the signal-plus-noise from the two groove walls and switches to one or the other side wall when the signal-plus-noise of that side wall is less than that of the sum by a selectable amount.

I might add that the two channels are mixed in the lower frequencies, the crossover being at a rate of 6 dB per octave starting at 300 Hz. This eliminates vertical rumble and various annoyances that could crop up in switching low frequencies. However, some records-notably some of the laminated American Columbia 78s-have vertical components extending above 300 Hz, due to surface irregularities presumably caused by the material in the center of the record "sandwich." It was after discovering this that the three way Switcher was devised. This eliminated that problem and also yielded a further reduction in the switchable noises. All Packburn noise suppressors now in service have the three-way Switcher.

The above description is for lateral-cut records. The Switcher also has applicability to vertical-cut recordings. The Audio Noise Suppressor, in its entirety, has applicability to any audio medium where noise reduction is desired.

-Richard C. Burns, President, Packburn Electronics Inc. Dewitt, N.Y.

Too Rich for His Blood

Dear Editor:

At one time I had decided that among audio magazines yours was the only one worth reading, and so I let all other subscriptions expire. However, during the past year I have become annoyed at the increase in reviews catering to the wealthy audiophile. Although I spend comparatively large sums on audio gear (over $2,000 this year on three components), I cannot see why you are reviewing so many multi-thousand-dollar products.

I originally subscribed to Audio for several reasons, one of which was its reviews of high-quality, reasonably priced and sometimes "best-buy" products. If I want to read about the most esoteric and expensive equipment available, I will pick up a copy of Stereophile or The Absolute Sound. (Incidentally, I am presently getting from Stereophile's "Cheapskate" column what I used to get from Audio.) May I implore you to return to reviewing equipment of special value, unique features, innovative design, and the like before I let my subscription expire out of frustration!

-David Lansdown, Newhall, Cal.

Squealing Discs

Dear Editor:

I have encountered a problem with a Compact Disc. One of my new purchases was failing to load correctly on my Magnavox FD-2041 player. Upon closing the drawer, the player would emit a squealing sound and the error light would come on. With repeated attempts the loading would at last be successful with the player displaying the number of tracks.

I noticed that this disc differed from others in my collection in that it was manufactured in the U.S. at DADC, while the others were made in West Germany. The American-made disc has concentric ridges near the center hole while the German discs are completely smooth from disc edge to center hole. The German discs load flawlessly each time, with no squealing. I exchanged the American disc for another, and so far it loads successfully but still seems to squeal some. I was wondering if the different manufacturing methods have something to do with this. Perhaps the German (Polygram) methods are better. Anyone else have these troubles?

-Randy D. Moench; Watertown, S.D.

(Source: Audio magazine, Feb. 1987)

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