SIGNALS & NOISE (Letters to Editor) (Dec. 1988)

For the Record

Dear Editor:

As we come to the end of the '80s, it seems that CDs are "in" and records are "out." With people having more records than anything else on the market, I feel that the record industry should stay alive! Records still sound better than prerecorded tapes, and most people like to look at the bigger LP covers. To keep LPs strong, I feel it is essential to improve them. Using half-speed mastering, super vinyl (which gives a more quiet playing surface), and static-free rice paper as inner sleeves are just some suggestions to improve LPs.

I will admit that CDs are nice, since they are quiet and small, and soon I too will be obtaining a CD player. The fact remains that not all catalog will be available on Compact Disc. Further, I found that records sound better than analog CDs on a high-quality stereo system.

- Glenn Bucci Garden City, N.Y.

Forgotten History

Dear Editor:

I would like to commend Daniel Sweeney and Steve Mantz on their finely written article on solid-state amplifiers in the June issue ("An Informal History of Solid-State Amps"). It was very well presented, with a wealth of information for many interested audiophiles. I would, however, like to clarify some points and correct some minor factual errors and errors of omission.

First, some time frames need to be corrected. Indeed, the first publicly known adaptation of a full-complementary amplifier was produced as a construction project for Popular Electronics in 1972-1 believe by Dan Meyer of Southwest Technical Products. It was my original suggestion to Dan (while I was at Dynaco) for this concept which led him to do the project: The Tiger .01 amplifier.

Another point to make is that while the authors are absolutely correct in that C. F. Wheatley and a Mr. Kleinman at RCA were the very first to use the series output topology, they did this for entirely different reasons than I did.

They were dealing with the new (at that time, circa 1962-63) drift-field germanium power transistors which, due to the lattice structure of germanium, had tremendous leakage problems (IcE0) associated with collector-to-emitter volt age (VcE0) and exacerbated with elevated temperatures. They needed the series connection to make the devices even reasonably safe. Safe-operating-area problems (SOAR) were a thing of the future and were not even known until silicon power transistors were in universal use, circa 1965-66.

I believe that I was the first to use the series topology in output stages. How ever, I used it first in the Dynaco 400 in 1972. I then used the first output triple series in the SAE Mark 3C. Ampzilla was my third-generation use of the out put series topology.

Regressing a bit, I was the first to make a commercially available dual-differential, full-complementary amplifier, but it was with the SAE Mark 31B in 1973. This continued through the Marks IIIC, IVD, 2200, 2300, 2400, 2500, 2600, etc., up to this day. Ampzilla was a much later refinement of these original concepts.

The authors state that "No true Class-A amp has ever been produced for the mass market." This is incorrect.

In 1980, I received the only conceptual patent ever issued for a solid-state, pure Class-A power amp from the U.S. Patent Office. Subsequently, I produced (at Sumo) the Model Nine, a 70 watt/channel, pure Class-A amplifier which then retailed for $599. This has to be considered on the low end of the price scale and as close to mass market as you can get with this kind of product.

Finally, I am disappointed that two of our industry's great pioneering engineers were not mentioned. Bart Locanthi must be given credit for his famous T-circuit produced at JBL in 1965. He was the very first person I know of to use the full-complementary output stage. Also, in 1966, Sidney S. Smith of Marantz designed the Model 15, which certainly must be considered a milestone in solid-state design. (I feel privileged to have been the final design engineer on that product.) His drive circuit remains a virtual de facto standard in the world of solid-state amps, as does his use of the compound RAEF pair. Aside from all his previous tube designs, Sid must be considered one of the giants in our industry.

I would like to thank Sweeney and Mantz for mentioning me in their article with more than deserved praise. My work is merely based on the efforts and experiences of all those clever engineers whose brilliance fortunately preceded me.

-James Bongiorno; Santa Barbara, Cal.

Burning "Bridges"

Dear Editor:

When I sent in the forms for this years Annual Equipment Directory, I indicated that our two stereo amplifiers, the Krell KSA-80 and the KSA-200, can be converted to mono operation.

For publication, this was changed to read "bridges to 160 watts" for the KSA-80 and "bridges to 400 watts" for the KSA-200.

This change is inaccurate, as it mis represents the design concept of the amplifiers and will undoubtedly cause confusion in the marketplace. First, it is well known that bridged operation yields four times the unbridged power.

As printed, it appears that our units cannot do this. Second, it is also well known that bridging does not deliver good sonic quality. This is certainly in opposition to Krell's reputation and intentions. Further, in the KSA-80 owner's manual, we make the point very clear that the mono unit is not a bridged version of the stereo unit.

In technical terms, the KSA-80 and KSA-200 amplifiers contain two independent supplies. When programmed for mono operation, for the KMA-160 or the KMA-400, the supplies are joined and higher voltage taps are used. The unit then has double the number of output transistors, further increasing the safe operating area. The audio in put is also changed, from single-ended to balanced.

-Dan D'Agostino; Designer and Engineer, Krell Industries, Milford, Conn.

Consumer Clout

Dear Editor:

I would like to comment on the letter to "Tape Guide" from Steve Medel that appeared in the June issue ("Com plaint Department"). Both the writer and Herman Burstein, in his reply, criticized high-feature/low-quality products, implying that marketing concerns are leading to a deterioration of overall product quality. I believe this view puts the cart before the horse.

From my experience as an audio retailer, in marketing management at both American and Japanese companies, and now as manager of a market research program in consumer electronics, I will agree that sales are of utmost importance. But manufacturers rarely lead the consumer into making foolish choices. Instead, the marketing departments try their best to discover what their customers (retailers and consumers) are looking for, and then attempt to have their factories produce it competitively. Certainly many trade offs in product design are possible, leading to the richness of choices we all enjoy. But if a product doesn't sell, you can bet the company will discontinue it. All efforts will turn to the combi nation of features and price that, hope fully, will better meet the customers' demands. The history of our industry is littered with "fantastic" products that few, if any, consumers wanted to buy.

It is my basic observation that the quality level of components today is high and edging upward. Even if this were not the case, an educated consumer, having read Audio and other magazines, could presumably find the combination of features, precision, etc. that best meets his or her needs. We, the buying public, have the power to direct the industry. When consumers vote with dollars, manufacturers listen!

-Clark Johnson, Port Washington, N.Y.

A Star Is Reborn

Dear Editor:

As a very critical listener/performer of early music, I spent a year deciding on my "last" turntable, a SOTA Star.

Because this company is committed to ongoing updates, they eventually caused me a problem. First, it would cost money. Second, I would lose my second favorite musical instrument (after my viola da gamba) for who knew how long.

To my surprise, two days after SOTA received my table, I got a phone call from Robert Becker. He told me that SOTA couldn't really upgrade my very early Star to their satisfaction. To my amazement, he then told me that SOTA had decided to replace my table with a current Series III, at no additional cost.

None! Nada! And from the head of the company! Five days later, my new Star was performing in my system. Let me tell you, no CD player could come close to SOTA's latest vacuum model--and perhaps no other turntable-for less than megabucks. But I am not writing to rave about the sound. I simply think this kind of support, motivated solely by SOTA's standards (and without pressure from me), deserves public notice. My other upgrade experiences have been far less rewarding.

With this kind of customer support, the LP will live forever. I hope good news travels fast.

-Peter Brewster Brown; El Cerrito, Cal.

Editor's Note: Yeah, but Becker is the only one with a key to the phone lock.

-E.P.

Whytewashed

Dear Editor:

It is very discouraging to read in your October issue that one must spend $6,500 just to extract a decent signal from a CD player ("Behind the Scenes") and that even the optical connections provided in high-end equipment are rotten.

I have several Compact Disc players, a very fine digital preamp, and numerous CDs, and can make my system sound as good with CDs as with a $1,500 cartridge/arm/turntable combo.

Let's face it: Some Compact Discs sound lousy, even if played through a Wadia, just as some LPs sound lousy even when played using the latest Koetsu phono cartridge.

What does Bert Whyte propose using as a CD transport suitable for connection to the Wadia? Surely not a Magnavox CD460. Perhaps a CD-ROM drive at about $1,500? In short, I think Bert Whyte's column is going to turn off, rather than turn on, those readers who have been sit ting on the fence with regard to the Compact Disc. I mean, wouldn't you question the feasibility of a playback technique requiring 72,000,000 calculations per second?

-Bernard A. Engholm, Carlsbad, Cal.

(Source: Audio magazine, Dec. 1988)

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