Right on, John ... it's that inner drive to truly get on top of the situation, in some scenario, that makes interesting things happen ...
That is because you had an unavoidable vocation JC........don't lessen it by calling it a compulsion.
You know, I think we are at the limit of rational discourse on these 'advanced' topologies.
I made them as simple as I could, but the lack of technical feedback or even questions, indicates that we have reached 'saturation' here.
Now don't feel bad: I 'saturate' when I attempt to read Maxwell's or Heaviside's books, and recently I got a book by Landau, that is 53 years old, and knocks me on my tail when I try to understand the material. I think it is, in my case, the lack of prerequisites in learning atomic physics that stymies me. Keep on Truckin!
I made them as simple as I could, but the lack of technical feedback or even questions, indicates that we have reached 'saturation' here.
Now don't feel bad: I 'saturate' when I attempt to read Maxwell's or Heaviside's books, and recently I got a book by Landau, that is 53 years old, and knocks me on my tail when I try to understand the material. I think it is, in my case, the lack of prerequisites in learning atomic physics that stymies me. Keep on Truckin!
I find this thread fascinating, thank you John for all your input. Sadly I don't know enough about electronics to add anything of note. My background is partly in electronics assembly, the rest is in electrical and mechanical engineering. The comparisons to car engines are quite good for us novices to read. I am well aware that even the very best engine design is wasted if something as simple as the timing is out by as little as one degree. Basic engines from decades ago will still run when out as much as 15 degrees and sometimes far more than that. This makes me realise that no area in electronics can be ignored if we are serious about achieving the very best results overall. Everything matters, or nothing matters.
None of us do. These circuits have been discussed to death; it's not quantum electrodynamics, it's some basic, simple amplification circuits. I'd be interested in anything new, especially if it carries a real advantage.
Davym, thanks for an accurate and considerate response. OF COURSE, these circuits are relatively obvious for Charles Hansen, Nelson Pass, and me. We have done this sort of level of audio design for decades.
I also realize that these circuits get difficult to get a good feel for, especially if you saw what we ACTUALLY design today. These schematics are just simplifications, it takes a lot more to get something that works ideally right, buffered from the power line and RFI, as well as direct coupled, input and output.
Please understand that the Vendetta Circuit of 30 years ago, is at least 8dB quieter than Scott Wurcer's AD797, one of the quietest IC's in the business, and the Vendetta input gain stage can run open loop, yet achieve .01% distortion at 10V out, with a feedback controlled second gain stage, and achieve 80dB of forward gain at 10 Hz.
Some people don't think it is worth it, so Parasound has provided an IC based phono stage that is almost as good, except for being about 10dB noisier. We get awards for that product too.
I also realize that these circuits get difficult to get a good feel for, especially if you saw what we ACTUALLY design today. These schematics are just simplifications, it takes a lot more to get something that works ideally right, buffered from the power line and RFI, as well as direct coupled, input and output.
Please understand that the Vendetta Circuit of 30 years ago, is at least 8dB quieter than Scott Wurcer's AD797, one of the quietest IC's in the business, and the Vendetta input gain stage can run open loop, yet achieve .01% distortion at 10V out, with a feedback controlled second gain stage, and achieve 80dB of forward gain at 10 Hz.
Some people don't think it is worth it, so Parasound has provided an IC based phono stage that is almost as good, except for being about 10dB noisier. We get awards for that product too.
Davym, I like automobile analogies too, but I often get criticized for it when I use it.
I too used to work on cars, and even 'hop' them up, starting with the late '50's, when I put dual carbs on my 1954 Chevy. Was I very successful? Not really, except for the learning experience. In 1968, I bought a SAAB Sonett and changed the carburetor to a dual throat Weber, put in a 3/4 cam, milled the heads, and changed the valve springs. It DID help, but what a hassle over the years. Finally, in the early 90's I bought a Porsche 924, and did every modification I could get away with with some limited success. I also learned the hard lesson that a VW based engine has real problems with being in a sports car, it just isn't designed for it. In any case, I LEARNED, and that was the point of the exercise. Today, I don't touch my cars, except for a quality air cleaner.
I too used to work on cars, and even 'hop' them up, starting with the late '50's, when I put dual carbs on my 1954 Chevy. Was I very successful? Not really, except for the learning experience. In 1968, I bought a SAAB Sonett and changed the carburetor to a dual throat Weber, put in a 3/4 cam, milled the heads, and changed the valve springs. It DID help, but what a hassle over the years. Finally, in the early 90's I bought a Porsche 924, and did every modification I could get away with with some limited success. I also learned the hard lesson that a VW based engine has real problems with being in a sports car, it just isn't designed for it. In any case, I LEARNED, and that was the point of the exercise. Today, I don't touch my cars, except for a quality air cleaner.
Scott,
> If you want Linear Systems to succeed in selling FET's ....
I don't think that is the justification not to discuss.
> it does not help to have threads where a bag of 50 NOS Toshiba's only yield 2 sets of matched quads......
A box of 2000 will have MUCH better yield.
But it is still better to have (selected) duals.
Patrick
> If you want Linear Systems to succeed in selling FET's ....
I don't think that is the justification not to discuss.
> it does not help to have threads where a bag of 50 NOS Toshiba's only yield 2 sets of matched quads......
A box of 2000 will have MUCH better yield.
But it is still better to have (selected) duals.
Patrick
Jeez my golf buddies light up the big stogies, it's the only place they can do it with impunity anymore. I never smoked myself.
It was nice to see Nelson again, how come he can openly discuss tuning the distortion of the electronics to suit personal taste without getting any flak? I have no problem at all with his approach, there is always an element of simulacrum in reproduced live sound.
My SIT JFET power amps will get a selector for "distortion level"..
Actually it is more than the distortion that changes.
I will actually implement this as a remote controlled function as this is just like the matching of JFETs in one additional dimension...
So playing at different SPL levels there are different levels of the "distortion" setting that are optimal.
The truth is that the way this is implemented was not for distortion control, but a way of linearize a JFET (class A power amp) differential stage under running conditions to avoid the need of a one dimensional current matching.
However it affects the distortion spectrum and level and thus the fidelity by a much higher degree than expected. And when I first have started fiddling with this adjustment there is no way back and it simply have to be implemented remote controlled.
John did you spend alot of time in the UK , a 3/4 race cam and your almost british level sarcasm is a dead give away , if only Sy knew how great a poet you are when not doing circuits ...
John Curl - Wikipedia, the free encyclopedia
Thanks for your reply's John. I never had that much success with taking mass produced engines apart and modifying them, any small gain in power was always at the cost of reliability. What I learned from this was not to waste money in this way, instead, buy something decent and try to keep it as close to the manufacturers original spec. I gave up completely on brit motors back then and bought used VW's or BMW's and just kept them well serviced. I have learned a lot by reading your posts here and what you say about discrete devices being better than op amp's is absolutely spot on in my view. For years now I fell into the trap of believing the hype that modern is best and modern is IC's all the way. I now know better and am currently enjoying a very cheap Chinese clone of your excellent JC-2. It amazes me how open and engaging it sounds compared to my previous attempts with chip based amp's which cost far more money.
Slainte Mhath my friend.
I found 70's & 80's London quite an unfriendly place to visit as a Scot
I am currently taking part in a group build for the My-Ref Fremen Edition chip amp build. My plan is to then build one of the Nelson Pass class A amp's, probably next year. I can then run both and compare the good and bad points of each. I will definitely stick to discrete designs from now on with line level and headphone amps as I have made up my mind about the merits of them in this capacity. I think IC's are responsible for the rise in interest in valve based amp's, I've had and built a few of them but they caused more problems than they solved in my opinion.
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