If I put my notes here, I might be able to find them again later!
Jenson JE-990 discrete op amp
LTSpice copy (protection diodes removed) of the original JE-990 circuit. Even with BC327/337 subbed in for all the original transistors the simulation works without further modification.
C1 seems to be critical for stability. C2 and C3 damp overshoot seen on the simulated square wave response, hinted at by the high frequency rise in frequency response shown in the screen grab below.
My impression is that this circuit is of the heavily optimized, no-stone-left-untouched variety.
Sourced from m.nats page and The John Hardy Company.
C1 seems to be critical for stability. C2 and C3 damp overshoot seen on the simulated square wave response, hinted at by the high frequency rise in frequency response shown in the screen grab below.
My impression is that this circuit is of the heavily optimized, no-stone-left-untouched variety.
Sourced from m.nats page and The John Hardy Company.
Total Comments 2
Comments
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Steve Hogan and John Hardy posted history of the JE-990 over at -
Steve Hogan's comments
John Hardy's commentsPosted 15th June 2015 at 04:38 AM by disfunctionalshadow -
Posted 16th June 2015 at 12:56 AM by rjm