Good post Erik
The Carver Amp Challenge and the 21st Century and it's Failure
Some of you may be old enough to remember this article from Stereophile. Bob Carver claimed he could make an amplifier audibly indistinguishable from some of the best from Conrad Johnson. A high efficiency (not class D), solid state linear amp vs. a linear tube amplifier.
https://www.stereophile.com/content/carver-challenge
Carver's approach was to feed a speaker via both amps at the same time using opposite terminals. The speaker itself was the measure of accuracy. Any difference in output between the two amplifiers would cause audible output.
What's super important here is Carver invented a new way to measure the relative difference of amplifiers with a real load.
That's kind of revolutionary from the standpoint of commonly published measurements of amplifiers before. Steady state, frequency sweeps, THD, IM and S/N all failed (to my ears) to express human experience and preference. I remember a reviewer for Audio, I think Julian Hiirsch, who claimed that these primitive measures were enough to tell you what an amplifier sounds like. The man had no ear at all, in my mind. More here:
https://www.soundandvision.com/content/reconsidering-julian-hirsch
And here was Carver in 1985 cleverly showing that two amplifiers which measured reasonably well, sounded differently. We should also be in awe of Carver's ability to shape the transfer function on the fly. That's pretty remarkable too but not the scope of this post.
My point is, really, Carver showed us a revolutionary way to examine differences between gear in 1985 and yet ... it did not become widespread. << insert endless screaming here >>
As far as I know (and that is very little) no manufacturer of any bit of kit or cable took this technique up. We are still stuck in 1985 for specifications, measurements and lack of understanding of what measures cause what effects and end up cycling through cables and amps based on a great deal of uncertainty.
My points, in summary:
Best,
E
https://www.stereophile.com/content/carver-challenge
Carver's approach was to feed a speaker via both amps at the same time using opposite terminals. The speaker itself was the measure of accuracy. Any difference in output between the two amplifiers would cause audible output.
What's super important here is Carver invented a new way to measure the relative difference of amplifiers with a real load.
That's kind of revolutionary from the standpoint of commonly published measurements of amplifiers before. Steady state, frequency sweeps, THD, IM and S/N all failed (to my ears) to express human experience and preference. I remember a reviewer for Audio, I think Julian Hiirsch, who claimed that these primitive measures were enough to tell you what an amplifier sounds like. The man had no ear at all, in my mind. More here:
https://www.soundandvision.com/content/reconsidering-julian-hirsch
And here was Carver in 1985 cleverly showing that two amplifiers which measured reasonably well, sounded differently. We should also be in awe of Carver's ability to shape the transfer function on the fly. That's pretty remarkable too but not the scope of this post.
My point is, really, Carver showed us a revolutionary way to examine differences between gear in 1985 and yet ... it did not become widespread. << insert endless screaming here >>
As far as I know (and that is very little) no manufacturer of any bit of kit or cable took this technique up. We are still stuck in 1985 for specifications, measurements and lack of understanding of what measures cause what effects and end up cycling through cables and amps based on a great deal of uncertainty.
My points, in summary:
- Most of what we consider state-of-the-art measurements are stuck in the 1970s.
- There are a number of ways to improve upon them
- No one has.
- We should be a little more humble when asserting if it can't be measured it isn't audible because our measurements are not nearly comprehensive
- I look forward to manufacturers or hobbyists taking modern equipment to pursue new measurement and new insights into our hobby.
Best,
E
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- 57 posts total
- 57 posts total