Charles Hansen said:
Yes I did.
Charles, if you mean complimentary JFETs on an IC, that’s never going to happen. We have experimented with it out of curiosity. I think they were P and N but far from truly complimentary. Take PMA’s circuit and compute the headroom it needs to the rails, more than a volt to both rails. Take some of the EC output stages presented in other threads, again several volts of headroom needed. These ideas might be great for audio, but aren’t universally useful. The high end business is far too fickle and fractioned. National put out an “audiophile” version of one of their amps in a TO can (I still think Pease is LHAO) that’s about as far as I can imagine any major player going.
For every John Curl there’s a Tim de Paravicini. He has universal acclaim and Grammy winning recording that many consider one of the best ever made with lots of tubes and transformers BTW. On my last trip to Europe I spotted at least 4 or 5 impressive looking multi-$1000’s phono preamps. So how many John Curls are out there with 40 or 50 worshipful customers? I don’t know why it can’t be more “different” rather than “better” when things are at this level. I’m not the one who’s going to herd the cats. In fact no one is going to do it with a single IC design.
I just woke up to all this. 
I thought that I might carry on with some high level engineering discussions. Of course, everyone is allowed to follow along, and even contribute, if they have anything useful to contribute. The problem is what is 'useful' in a discussion like this.
I recall having a discussion in 1973 with Dr. R.G.Meyer on 3'rd order harmonic distortion cancellation due to local feedback. He gave me about 5 minutes, and then asked me to leave. My final question to him was whether higher order harmonic cancellation was also computed. His answer was no, at the time. Now, 1/3 of a century later, advanced Spice simulations on this website and the earlier work of Baxendall (sp) in 'W.W' gave me the answer I was seeking back then. Did I blame R.G. Meyer (who is the same age as me) for not wanting to me 'shoot the bull' with him? Not really, he was a full professor and I was just a design engineer. He had no need for my input at the time. Later when he did need my input, he was more attentive.
I am most attentive when I see real input on this thread, and will remain so.
I thought that I might carry on with some high level engineering discussions. Of course, everyone is allowed to follow along, and even contribute, if they have anything useful to contribute. The problem is what is 'useful' in a discussion like this.
I recall having a discussion in 1973 with Dr. R.G.Meyer on 3'rd order harmonic distortion cancellation due to local feedback. He gave me about 5 minutes, and then asked me to leave. My final question to him was whether higher order harmonic cancellation was also computed. His answer was no, at the time. Now, 1/3 of a century later, advanced Spice simulations on this website and the earlier work of Baxendall (sp) in 'W.W' gave me the answer I was seeking back then. Did I blame R.G. Meyer (who is the same age as me) for not wanting to me 'shoot the bull' with him? Not really, he was a full professor and I was just a design engineer. He had no need for my input at the time. Later when he did need my input, he was more attentive.
I am most attentive when I see real input on this thread, and will remain so.
The same idea works for an output stage and an "H" bridge input stage. We use it on inputs but the headroom penalty at high output currents makes it not useful in the output stage.
BTW John do you know Bruce Wooley? A fellow Milwaukeean doing well at Stanford. I understand being shunned by the academics from "the other side of the tracks".
BTW John do you know Bruce Wooley? A fellow Milwaukeean doing well at Stanford. I understand being shunned by the academics from "the other side of the tracks".
Scott, as you probably know, the challenge of output stage distortion minimalization was first done by Barney Oliver in 'Distortion in Complementary-Pair Class-B Amplifiers' back in the early '70's. The problem is that Barney did not care what harmonic was minimized, just so that the THD was lowest, and he even added higher order harmonics in one approach. This was unfortunate, but his article is still useful.
Do you have the ratio for Re vs Ic that minimizes 7th harmonic distortion? That would be interesting to me.
Do you have the ratio for Re vs Ic that minimizes 7th harmonic distortion? That would be interesting to me.
When we have compared power amplifiers in listening tests, all with reasonably low distortion, the designs with OLG roll-off frequency above audio band have been better accepted in general, provided there were no cross-over distortion and similar design flaws. Same for preamps. We can get fair results with opamps and power opamps, but not the top results. 800kHz fT is very, very low.
john curl said:
Sure. But your statement says implicitly that good measurements equals good sound and better measurements equals better sound. It's only a distinction of what's being measured.
And while you have said "Listening is more important than measuring," I don't believe I've ever seen anything from you where the two are not implicitly ultimately one and the same. That if something sounds better, it inherently must be because some aspect or other(s) measures better.
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