Critic's Corner: RE: Misplaced Manufacturers' Comments by Charles Hansen

< < this is about another company's product > >

I don't really see how you got that out of my letter. It is about the new ultra-low distortion op-amps recently introduced by National. (Burr-Brown has also recently introduced some ultra-low distortion op-amps, but they are less suitable for audio as they can only handle +/- 5 volt rails instead of the +/- 17 volt rails of the National parts.)

But even mentioning this product was only to illustrate a point. The entire point of the letter was that JA had wrote a piece on the Stereophile website telling about these new parts. In it he wrote a comment that I disagreed with, namely that there is a strong correlation between low measured distortion and good sound quality.

I've been doing this for long enough to know that this is simply not true. During the '60s, the mainstream audio magazines would test preamps and there were measurable deviations from flat frequency response and relatively high levels of distortion. Then there was a breakthrough -- the Crown IC-150 preamp had vanishingly low levels of distortion and perfectly flat frequency response.

When that test report was printed, I thought to myself that we had reached the end of the road. How could anyone improve upon perfection? I was convinced that the IC-150 was the best preamp on the planet. (It was based on the newly introduced op-amps of the day.)

I was discussing this with a friend who worked at a stereo shop and owned an Audio Reasearch SP-3. He said that I was wrong and that there were significant sonic differences between preamps, even ones with essentially identical measurements. I was doing repair work at a high-end store, so we each borrowed a few preamps from our respective stores and dragged the whole mess to his house. In addition to the SP-3, we had a Crown IC-150, a Quintessence (highly regarded in it's day), a Dynaco PAT-5, and probably something else I can't remember any more.

He had Transcriptors turntable with the Vestigal arm, the ADC XLM cartridge, a Marantz 510 power amp, and a pair of Magneplanar Tympani 1B's. This was definitely a state-of-the-art system for those days (around 1973 or so).

I was stunned to hear such obvious differences between these products. I was even more stunned that the "perfect" IC-150 was clearly the worst sounding unit of the lot. So right then I learned that any correlation between low distortion and good sound quality was tenuous at best.

When JA resurrected this fallacy in his online column, I wrote him a private e-mail expressing my disappointment. He felt that my views were worthy of wider circulation and asked if he could print my missive in Stereophile. I agreed after a bit of self-censorship, and deleted the specific names of the products mentioned in my original letter. The point is not whether or not I think a certain product sounds good or not.

The point is that our industry cannot make real progress until we discard the previous unworkable models. Just as discarding the idea that the earth flat led to all kinds of advances in navigation and science, discarding the idea that low distortion will automatically give good sound quality will also lead to advances in sound reproduction. I personally feel that this point was demonstrated over 30 years ago quite well, and felt that it was appropriate to point out the fallacy in JA's article.

< < it seems a dangerous precedent for Stereophile > >

I think that the dangerous precedent is when someone makes a statement regarding the sound quality of a product without actually listening to it. Which is why I wrote the letter in the first place.

Now one of the things that I admire greatly about JA is that he is not afraid to give "airtime" to people that don't necessarily subscribe to his views. I am sure that if some manufacturers want to respond and make a case for why op-amps are better than discrete circuits, or that low distortion *does* guarantee good sound quality, that he will also print those letters.

And in the meantime, I would be happy to discuss any substantive points or answer any pertinent questions. Here is a link to another posting I made on this topic:

http://www.audioasylum.com/cgi/m.pl?forum=amp&n=121090

Ultra-low distortion op-amps from National (Open in New Window)