I see no reason to doubt that horns could sound good.
But I have to point out that one of the worst experiences with audio I've ever had was with Classic Audio. I want field coils and horns to be great, but I haven't heard it yet.
But I have to point out that one of the worst experiences with audio I've ever had was with Classic Audio. I want field coils and horns to be great, but I haven't heard it yet.
Memory Distortion.
Damir,
Yes your circuit looks similar but have a more accurately look at your circuit and mine, yours
Is mainly composed from improveded cascodes (constant voltage around the input device).
Gerard Perrot patents and the circuit I presented here have constant power on the input device, constant voltage and constant current on the input device.
The rule is to forget the rules but knowing all the rules.
Damir,
Yes your circuit looks similar but have a more accurately look at your circuit and mine, yours
Is mainly composed from improveded cascodes (constant voltage around the input device).
Gerard Perrot patents and the circuit I presented here have constant power on the input device, constant voltage and constant current on the input device.
The rule is to forget the rules but knowing all the rules.
Richard,
Yes I know it's not complete solution for the memory effect(constant power). I've read some years ago about it here: Memory Distortion Philosophies - Part 1 : Theory very interesting.
Here is complete document: http://www.pearl-hifi.com/06_Lit_Ar...unction-Memory/Junction-Memory_Distortion.pdf
Damir
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These are exactly the points made by Arto Kolinummi in his Linear Audio book. Try to keep currents through and voltages across device as constant as possible: https://linearaudio.net/books/2220
See also Jacques Exbrayat's Vol 10 article with a single transistor handling the audio, relegating voltage and current control to the periphery and ending up with A minimal structure high-performance voltage follower / amplifier.
It is also the idea behind Nelson Pass' 'stasis' concept IIRC.
Jan
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Amusing, $39,000 of cables and the field coils are excited by $100 Chinese eBay power supplies.
Talking of progress, and having a giraffe. https://www.theoretica.us/bacch-sp-grand/index.html
Only works for the lonely audiophile though.
Only works for the lonely audiophile though.
Markw4, thanks for your input. Still, I am somewhat sensitive to people telling me how I personally hear, especially when I disagree with them.
Now, Scott and I have known and worked with each other for about 1/3 of a CENTURY. You must agree that that is a long time. I used to call Scott regularly for help on some (non-audio) projects that I was working on, as well as audio projects, and I was extremely grateful to him for his help. He saved me a lot of time on my professional job at the time (a medical laser) giving me his experience in RF bypassing, etc. He also supplied me with exotic IN-AMPS that I found very useful for differential measurements. Our 'falling out' happened about 10 years later, apparently when I removed an IC from my first Parasound power amp in order to hope to improve its sound quality to make it acceptable to audio reviewers. The IC happened to ultimately be one of Scott's designs (AD712) that I had personally chosen as the best IC that I could find at the time to do the job. In removing the IC, and any other changes that I could do at the time, a second review of the Parasound amp passed the listening quality test, and I was able to keep my job with Parasound.
This set off a problem with Analog Devices and at least one written complaint was submitted to the magazine from someone there. I think it was Walt Jung, who ironically probably was forced to write the complaint. '-)
However, since then, telephone conversation, and any other, except accidentally running in to each other at conferences, etc, has been terminated.
Now what has this to do with how I listen? Everybody knows that I have had trouble with ABX listening tests. I have put this in print since 1979 in TAA in LTE's. I appear to be especially crippled by ABX tests, so I don't use them, for it makes me virtually deaf to differences under that test, as I always lose track of which component I am listening to.
However, when I can keep track of the component (even if I don't know specifically whether it is A or B) but know that I am listening to either A or B at any given time, I do better than average, so I keep to it. Is this 'cheating' or 'peeking'? Yes, I guess, and I have to work extra hard not to be biased toward any particular device, but I seem to muddle through successfully.
Now, this thread has continually run over 10 years and I have said many things, even about my listening preferences, and I am sure that somebody, somewhere, just like in a courtroom situation can manufacture evidence that I am untrustworthy and inconsistent at times, but it has never been deliberate. Therefore I have to repeatedly restate my position on listening tests, in order to keep my true opinion from being buried by the opinions of others. I doubt that Scott and I will ever be close colleagues again, too much has passed between us, and I am equally responsible for the negativity, but not all of it.
Now, Scott and I have known and worked with each other for about 1/3 of a CENTURY. You must agree that that is a long time. I used to call Scott regularly for help on some (non-audio) projects that I was working on, as well as audio projects, and I was extremely grateful to him for his help. He saved me a lot of time on my professional job at the time (a medical laser) giving me his experience in RF bypassing, etc. He also supplied me with exotic IN-AMPS that I found very useful for differential measurements. Our 'falling out' happened about 10 years later, apparently when I removed an IC from my first Parasound power amp in order to hope to improve its sound quality to make it acceptable to audio reviewers. The IC happened to ultimately be one of Scott's designs (AD712) that I had personally chosen as the best IC that I could find at the time to do the job. In removing the IC, and any other changes that I could do at the time, a second review of the Parasound amp passed the listening quality test, and I was able to keep my job with Parasound.
This set off a problem with Analog Devices and at least one written complaint was submitted to the magazine from someone there. I think it was Walt Jung, who ironically probably was forced to write the complaint. '-)
However, since then, telephone conversation, and any other, except accidentally running in to each other at conferences, etc, has been terminated.
Now what has this to do with how I listen? Everybody knows that I have had trouble with ABX listening tests. I have put this in print since 1979 in TAA in LTE's. I appear to be especially crippled by ABX tests, so I don't use them, for it makes me virtually deaf to differences under that test, as I always lose track of which component I am listening to.
However, when I can keep track of the component (even if I don't know specifically whether it is A or B) but know that I am listening to either A or B at any given time, I do better than average, so I keep to it. Is this 'cheating' or 'peeking'? Yes, I guess, and I have to work extra hard not to be biased toward any particular device, but I seem to muddle through successfully.
Now, this thread has continually run over 10 years and I have said many things, even about my listening preferences, and I am sure that somebody, somewhere, just like in a courtroom situation can manufacture evidence that I am untrustworthy and inconsistent at times, but it has never been deliberate. Therefore I have to repeatedly restate my position on listening tests, in order to keep my true opinion from being buried by the opinions of others. I doubt that Scott and I will ever be close colleagues again, too much has passed between us, and I am equally responsible for the negativity, but not all of it.
Justcallmedad and dadod, I like both of your designs and am glad to see some here really putting out interesting schematics. Your circuits are very similar to what Charles Hansen and I put out for hi end audio products. Both of you are on the right track, and we ALL have differences in design preference, and that is what makes it interesting!
Please allow me to ask a question, was it the same reviewer who made the second review and was he aware of the IC removal? What were "the other changes" made at the time?
Thank you,
PMA, I asked the very same reviewer, just last month or so specifically about this. The reviewer was Robert Harley, then a reviewer for 'Stereophile' and now Editor-in-Chief of 'The Absolute Sound'. He said that he ALWAYS listens first, without looking inside, and he did not know that there was an IC at the input until later when they made technical measurements. He did speculate (correctly) that the IC could be a problem, however. I don't remember any other significant changes at the time, but I independently established that removing the IC did make a real difference, by just bypassing my own personal unit, my associate Carl Thompsen (CTC partner), and Brian Cheney (VMPS) as well. What can I say? Perhaps it was the circuit? I don't know.
Which goes to Scott's (amusing to me) adage that if you look at any "audio" opamp, it has its litany of admirers and detractors.
Which kinda just makes you throw your hands in the air and give up on any sort of non-technical evaluation (e.g. listening "tests") and stick with the drier stuff (e.g. suggestions about opamp-in-question's surrounding circuit and tips about usage).
Which kinda just makes you throw your hands in the air and give up on any sort of non-technical evaluation (e.g. listening "tests") and stick with the drier stuff (e.g. suggestions about opamp-in-question's surrounding circuit and tips about usage).
Yes. And sometimes thorough set of measurements may indicate to problems of particular implementation.
I did not like ABX tests in the past. But now, more and more, I do not rely on uncontrolled test. We may be biased, even if we believe we are not. The sound perception is really very complex.
In this case it was not an audio op-amp but our first low cost plastic general purpose op-amp. At the time Walt Jung was popularizing the use of JFET op-amps as I/V's in CD players. IME the improvements could be traced to actual measurements of things like out of band spurs and HF IM effects. Maybe John needs a gentle nudge to remind him that he repeats this story on a quarterly basis (if not more often).
We may say that the AD712 was just the better TL072, right?
Of course, the simple observation that trimming the supply current eliminates the tails on performance was of great value. In the day some customers had issues with general purpose parts having a little too much/little BW, etc. in some batches making their boards oscillate or not drive the load. Especially things like LF356 with huge Isupply range.
If John can repeat stories so can I. Akio Morita's personal golden ear insisted that the AD712 be used as the I/V in (at the time) SONY's top of the line CD player. It was too expensive for their run of the mill units though.
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Hard to argue with this stance (well, I'll let someone give it a go!), and I think we're saying the same thing in different language.
Scott-- didn't know the back-story, but wrote "audio" in acknowledgment that it's a rare opamp to be designed for audio-first rather than coopted to the purpose.
John,
It would seem a run (maybe 25 ?) of the Constellation Audio Orion phono stages were actually made, did you end up with one? Is the main difference between the Orion and the Pegasus phono stage that rarer dual Toshiba jfet input devices with smaller source resistors were used for a lower noise input stage?
Any construction details like teflon Riaa caps, Bybees, parralled jfet local regulation?
It would seem a run (maybe 25 ?) of the Constellation Audio Orion phono stages were actually made, did you end up with one? Is the main difference between the Orion and the Pegasus phono stage that rarer dual Toshiba jfet input devices with smaller source resistors were used for a lower noise input stage?
Any construction details like teflon Riaa caps, Bybees, parralled jfet local regulation?
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