Protection or performance?

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Sometimes we make great decisions other times not. This is a tale of not, but includes alesson.

In the early 1980's a very gifted amplifier designer, Bob Odell, joined the company and with him a new design of a power amp - to be introduced as the 200C. We spent a lot of time on the amp, tweaking, changing, doing what we could to maximize its sonic performance.

One bone of contention between myself and Bob was an output inductor - which had no measurable affect within the audio band but you could hear it none the less. Bob insisted on including the ultasonic filter on the output of the amplifier because use of that filter made the amplifier unconditionally stable and safe. I objected to the inductor for performance reasons - the filter made the amp sound too sterile.

Just before we were to release the final design we decided to settle the issue with a sonic shootout. We performed the test on a system that had far more resolving power than ours: the Infinity IRS. Our friend Arnie Nudell, one of the best listeners in the industry, had a pair setup in his home and to LA we went for the big shootout. The question at hand: how much of a performance compromise did the inductor present?

We played the amplifier on the big IRS for some time - Arnie being polite but unimpressed. I remember a particular album we were playing had a magnificent piano piece and frankly, it was good but not stellar. The Audio Research reference amplifier was far more musical.

I then took a pair of clip leads, shorted out the output inductor and replayed that piano piece. Arnie and everyone else in the room lit up like a veil had been lifted. "Now THAT sounds like a piano!" Arnie was right, the piano had bloom and overtones not present with the inductor.

"McGowan, whatever you did, do that in production and you have a winner!" Arnie proclaimed.

Bob Odell, on the other hand was as nervous as a cat about this decision. He too wanted the sonic gifts of no inductor but knew the amp would be less reliable. So I questioned him and found that we'd be fine as long as no one disconnected or connected anything to the amp's inputs while it was on. So that was it. We went with the better sounding version and put a big warning on the back of the amp. "Do not make any connections to this amp when the power is on".

It only took about 25 amplifiers going up in a puff of smoke to realize we hadsacrificedprotection for performance. Seems most people either never saw the warning or ignored it.

We finally figured out a good compromise to make the amp stable and sound good but learned a great lesson as well.

The decision between protection and performance should not be made lightly.

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Paul McGowan

Founder & CEO

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