SIGNALS & NOISE (Letters to Editor) Sept. 1985

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A Real Team

Dear Editor: It seems to me that in recent years your annual Lirpa issue had become a little strained, but this year's issue was right on track. I especially liked the design philosophy espoused by George V. Dajan and the down-to-earth advice of Namreh Nietsrub.

Until next year, meanwhile, I shall continue to derive similar pleasure from the humorous reviews of Laurence L. Greenhill and David L. Clark.

By the way, how long can the boys continue the pretense that their first names aren't Bob and Ray?

Send Flowers

Dear Editor: I was very intrigued by Prof. Lirpa's method for perfecting a stereo system by straightening the power amplifier cord (see "Tape Guise," April 1985). The "straight wire with gain" concept yielded astounding results, as I shall relate. You see, in my haste to carry out the Professor's method, I misinterpreted some of his directions.

As I understood it, the idea was to relocate the amplifier where one could detect a clockwise rotation-namely the bathtub. As it happened, the power cord was at its straightest when I held it in that location! Even with all the leads disconnected, the sonic (and other) effects that I experienced while turning the amplifier over in a bathtub full of water gave me new respect for the concept of a straight wire with gain. When I get out of the hospital, I'm going to try improving my TV picture the same way.

No Niche Needed

Dear Editor: I would like to lend my support to Roy Allison's comments about the recent turn that your magazine's editorial content has taken (see "Signals & Noise," April 1985). I can think of two specific instances, an "Auricle" and an "Equipment Profile," where brevity and/or lack of objective data have deprived readers of needed information.

The feature article "NAD's Floppy Tonearm" in the February 1984 issue was very interesting, but obviously written by the product's designer.

Longtime Audio readers were certainly as disappointed as I was to see the NAD 5120 turntable given such a cursory review in the same issue. The effect was to buttress a PR push, and this is not what I have come to expect from Audio. A new and unusual design like NAD's demands more rigorous examination.

Similarly, I would have liked to have seen more data on Sony's new D-5 portable CD player. As a D-5 owner, I have been very curious about its technical performance-I get a rising (!?) response in the top two octaves, for example-and the "Auricle" in the March issue told me very little that I couldn't have gleaned from the promotional literature.

Audio is the only magazine in the "High Futility" industry whose reviews I respect. The "Auricle" profiles combine the superficial aspects of the more consumer-oriented press with the golden-ear silliness of the little magazines. I don't think that Audio needs to make a niche for more of that particular kind of writing.

Tubes into Transistors

Dear Editor: As one who believes that tube amplifiers should not contain transistors, I was disturbed that the Lirpa 1 amplifier (described in "The Perfect Amp: Zero Distortion" in the April issue) uses a transistor at 01, and I determined to disprove the article's statement that this transistor "is irreplaceable by any vacuum tube." Since Appendix I shows how to modify a transistor for this application, perhaps there is also a way to modify a tube. And there is.

Start with one of the metal tubes introduced just before World War II. Choose one without a grid cap-a 6C5 or 6H6 would be suitable. One that does not test "good" is okay-in fact, please do not use a good one, as they are no longer made, and surviving stock is required by antique radio collectors for restorations.

Drill a hole through the metal top in the center. The vacuum, which is not used in this application, will then escape through the hole. When it has all leaked out the tube should be filled with mercury, poured in through the same hole. That's all there is to it! A problem sometimes experienced with tube amplifiers is microphonics, caused by mechanical vibration of the tube electrodes. With this modification, there will be no such problem because of the excellent damping provided by the mercury.

Some people expect this tube to emit blue light in operation. This is because they confuse a mercury-filled tube with a mercury vapor-filled tube, such as the 83, which does emit blue light. This tube is triply protected against emission of blue light, since the metal envelope is opaque to blue light, the mercury also is opaque, and there is nothing in the tube to generate blue light in the first place.

Blowing Their Horn

Dear Editor: I would like to add a kudo that should at least equal those published in your April "Signals & Noise." Klipsch and Associates has to be the most conscientious audio manufacturer I have dealt with in over 30 years of hi-fi experience.

When I bought a pair of used, 21 year-old Klipschorns recently, I found that replacing the original drivers with updated Klipsch units exacerbated a mysterious problem in the middle and upper range of the system, and no one could figure out what it was. Finally, I sent the top sections of both horns down to Klipsch and they replaced horn, driver and crossover components, and the mounting flanges-free of charge! They even sent them back prepaid! The speakers sounded great (even more so with the addition of Klipsch's newest crossover). I think that this kind of treatment, of the owner of a used product that was old enough to vote, must be some kind of record for commitment and a sense of long-term responsibility for one's products that goes well beyond any ordinary warranty. It surely is one reason for the continuing respect held for Klipsch products.

(Source: Audio magazine, Sept. 1985)

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