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Thanks to Mr. Pass and the two interviewers for their 2 great videos. It is a pleasure for me to see and hear Mr. Pass express thoughts and recount memories. Watching him is time well spent.
Best
Anton
The input jfet would presumably still be a p-channel. And maybe its source is connected directly to the output via low value feedback resistor, and no connection to V+ ??
I have a theory question.
the f8 will be a all jfet design and the distortion will be dominated by the 2nd distortion.
I've seen a youtube video explaining that dropping the degradation simplifies the distortion character, getting rid of most high order distortion. I recall reading an article about exploiting the square law character of jfets and I could swear that they said as fet operates closer to its optimum character the 2nd order distortion lowers in comparison to the 3rd distortion.
I assume that the j2 and f8 would be operated within there sweet spot. So why is the f8 distortion character primarily 2nd? Is it that current feedback targets odd order distortion more than the even order distortion?
Or have I missed a step somewhere?
the f8 will be a all jfet design and the distortion will be dominated by the 2nd distortion.
I've seen a youtube video explaining that dropping the degradation simplifies the distortion character, getting rid of most high order distortion. I recall reading an article about exploiting the square law character of jfets and I could swear that they said as fet operates closer to its optimum character the 2nd order distortion lowers in comparison to the 3rd distortion.
I assume that the j2 and f8 would be operated within there sweet spot. So why is the f8 distortion character primarily 2nd? Is it that current feedback targets odd order distortion more than the even order distortion?
Or have I missed a step somewhere?
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the error amplifier / input device is single ended, H2 usually dominates in this case, unless there’s a fortuitous cancellation of H2 between stages of the amp.
current feedback implies nothing about H2 vs H3 per se, it simply says that the feedback is to a low impedance node (source) instead of a high impedance node (gate).
fyi - a long thread on the solid state forum concluded, as I expected, that CFA and VFA are two sides of the same coin.
current feedback implies nothing about H2 vs H3 per se, it simply says that the feedback is to a low impedance node (source) instead of a high impedance node (gate).
fyi - a long thread on the solid state forum concluded, as I expected, that CFA and VFA are two sides of the same coin.
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There will be no fortuitous cancelling here. Both stages have the same polarity
of 2nd harmonic.
of 2nd harmonic.
well, if someone is exaggerating here, that's certainly not Papa, but your truly
F8, as Papa said in several later interviews, is not so different from J2, speaking of sound
different enough, but similar in character - which means no syrupy ingredients
F8, as Papa said in several later interviews, is not so different from J2, speaking of sound
different enough, but similar in character - which means no syrupy ingredients
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In general, cancellation of H2 between stages of the amp is considered to be a good thing?
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It’s usually only relevant for H2 and harks back to the days of open loop tube amps. If H2 is excessively high such cancellation is often beneficial but it might depend on parameters that change with age of the parts. It’s not a design approach I use or prefer.
I would add that distortion is a varied beast. A little can sound nice, add character. Too much and your amp is good only for simple music, for complex stuff the IMD creates a muddy sound.
I would add that distortion is a varied beast. A little can sound nice, add character. Too much and your amp is good only for simple music, for complex stuff the IMD creates a muddy sound.
another Jewell from SR:
"Build more, speak less"
translated from Yore : "Proof is in da Pudding"
which is, again, having roots in Yore Ma , saying : "Eat ya Porridge every morning, ya'll be big and strong!"
"Build more, speak less"
translated from Yore : "Proof is in da Pudding"
which is, again, having roots in Yore Ma , saying : "Eat ya Porridge every morning, ya'll be big and strong!"
Any ideas what the JFET (SIT) device will be? Will they Pa's remaining devices from Semisouth or something entirely new?
Per the interview linked in post #1 (about 10:30 in), the output devices are the same as
those in the J2.
those in the J2.