What you are saying here implies that you believe that those ' other factors' cannot be found inside the realm of moving electrons. The logical conclusion is that, in your eyes, electronics is the wrong discipline to improve amplifier performance.
I agree.
Amplifier performance has increased to a level where further technical improvement has become irrelevant to humans.
Bcarso, what Scott is saying about Richard Heyser is not fair to Richard, or anyone else. Richard lived into the mid '80's, and he was an audio reviewer for 'AUDIO' until his death. He had plenty of time to test TIM, SID, fully complementary designs, etc. He never told me that he changed his opinion. He just talked about the 'multidimensional' aspects of subjective audio quality.
When Richard Heyser said anything, I listened. I am not the only designer who did, as well.
Of course, 95% of anything that I design has global negative feedback. My only truly open loop designs are the Vendetta Research input stage, the Constellation phono input stage, the Audible Illusion's phono input stage, and the CTC Blowtorch. All are very successful designs(or will be) against ALL comers. I would do more, but Parasound is not a practical venue for a zero feedback design.
When Richard Heyser said anything, I listened. I am not the only designer who did, as well.
Of course, 95% of anything that I design has global negative feedback. My only truly open loop designs are the Vendetta Research input stage, the Constellation phono input stage, the Audible Illusion's phono input stage, and the CTC Blowtorch. All are very successful designs(or will be) against ALL comers. I would do more, but Parasound is not a practical venue for a zero feedback design.
Last edited:
You realize that might be coincidental to class D and SMPS being used, right? We don't have anything to the contrary.
I know he is respected and had some good ideas. I would have to evaluate his beliefs in terms of his psychology, i.e., once he came to a conclusion did he ever reevaluate and reconsider?
I have had friends who would reach a conclusion and never change it. For one of them I could see the transformation and know that there was no turning back. Once I committed an error in identifying a functional chord in the middle of a concerto to which we were listening. It was a stupid blunder and one performed under the influence of at least a couple of popular substances, and I retracted it when the error was pointed out (calling a V chord a 6-4 chord of the tonic, which two have similar functions in classical/romantic music to announce the beginning of the soloist's cadenza). Of course I knew the difference, but the transformation was underway, and the guy called me a musical idiot savant. He declared this with a palpable sense of relief, as if he finally understood something for the first time.
Well, I should have pointed out immediately that, to begin with, I wasn't an idiot. But it had previously emerged that this person (with a PhD in physics) had gone back to school in music primarily in order to eventually show me up as an inferior-to-him composer/musician. Since he also believed that simply by working hard he could compensate for years of neglect of such studies, when this didn't work out he had to find another reason for my particular prowess. I gave him a datum for his theoretical way out.
My point is: if Heyser perceived a problem with feedback and was the sort of person to "stick to his guns", he may never have revisited the issue---no matter how much listening, thinking, and reviewing he might do.
Bruno has done plenty of other designs besides class D. You may have read his first piece (The F word) for Linear Audio in which he describes a tube amp around which he applied a lot of feedback. Since the forward gain was not nearly as stable as a competent solid-state design, it was difficult maintain stability over time---but he reports that listeners were pleased with the sound.
The guy knows what he is doing.
Whenever I see discussions of audibility vs. classical distortion measurements I see an assumption of monotonicity. For modern amplifiers this is almost never true. JC is the only poster to this section of the thread to include this critically important point. The rest of us are wrong-headed.
All good fortune,
Chris
All good fortune,
Chris
Blanket statement is a form of generalization. But there may exist a phenomenon where most amps with lots of negative feedback sound subjectively inferior...
That's possibly one of the reason why amps with lots of GNFB sound subjectively inferior. Not the NFB itself, but the designer does not pay attention to the quality of each stage, hoping that the GNFB will fix everything...
It would be nice if we could put numbers on "very tiny" verses "small amounts." Maybe we can't, though.
Agreed about any misleading claims using the word fidelity, which would seem to amount to claims regarding measurable performance. On the other hand, expressing an opinion that something sounds better than something else should be okay.
Also, just as people can usually get better at discerning relative pitch with training and practice, it seems to me that most people can get better at hearing distortion in a similar way. That being my impression so far, I would be interested to see if any distortion threshold studies that have been done to date include some subjects trained to listen for it, and what effect, if any, such training has on detection ability.
Agreed he's very smart. But again a Tube amp isn't an example in mind either, necessarily. If he had some AB/A designs that were incredible, using transformer based PSU, I'd agree with the comments about engineering vs. design more so... in actuality I believe there's engineering factors that aren't represented well by how we take data. Those explain differences like JC is talking about, we just don't have overly great ways to explain any of it. The "design" factors are rather unexplained engineering.
But personally I haven't heard a Hypex product that blew me away, per se, but they certainly are good.
I don't think that is the (his) conclusion. Some people talk about measuring the wrong things. That implies that the 'other factors' are still inside the realm of moving electrons...
I don't think they have reached that level (at all)...
There are many variables in amplifier performance. What they need is to understand the relation of each variables with sound perception...
Yes, at the end they will have to deal with (or to understand) threshold of audibility of each variable...
And this is NOT the threshold of the designer's hearing ability!
As a commercial amp designer you need to hear what the market is saying. And if your hearing is acute and not easy to please, you will think harder. Only if your hearing is damaged and you don't design for other people you can believe on Richard Clark amplifier challenge and the likes...
Once you get some decent level of THD, like about 0.1% do the rest by ear. This is where good recordings of choral music really come in handy. Also Supertramp Breakfast in America - A bright, hyped pop recording that really wakes up IM with all the plate reverbs while the mix progresses with the song building a stereo spread. Sol Hoʻopiʻi Fascinating Rhythm - you can hear the 2nd harmonic of the lap steel. Get that 2nd harmonic sounding clean like a function generator sine wave. Beatles I Saw Her Standing There. Listen to the rhythm guitar, It's buried. The design needs to pull it out of the mix. I could go on. I know I sound like a child to you guys. But heck, this is what it's all about in the end; not some numbers.
Last edited:
By which you mean for example the transition from crossover distortion to other nonlinearities?
sorry but you simply can't be an up to date EE - we can make amps and measurements such that all errors are below human hearing threshold in quiet - when the amp is delivering enough power for 120 dB SPL with typical domestic loudspeakers, in typical home listening rooms
much easier to exceed the limits of real home listening room noise floor, actual recording mic, studio noise floors
not all amps do, it is a stretch - but within both amp and measurement technology - for decades now
Last edited:
at the SOTA - which in fact has moved beyond audio's demands, but maybe only for ~1 decade though with recent industrial/medical imaging ADC
a decade old example: http://www.ni.com/white-paper/3670/en/
a decade old example: http://www.ni.com/white-paper/3670/en/
Last edited:
In term of said variables, yes. How about the claim regarding measuring the wrong thing?
Like in all engineering designs, we often meet with trade-off. If we improve THD too far, we loss on other criteria. BTW, I'm very curious, what is the common trade-off for low THD (in the eyes of amp designers)?
Why not all amps? Is it too hard to do? Too expensive? Or only a few select designers know how to do it?
Or, every designers know, it is just the market that is too dumb?
- Status
- Not open for further replies.