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Jenson JE-990 discrete op amp

Posted 8th June 2015 at 07:45 AM by rjm
Updated 9th June 2015 at 12:09 AM by rjm

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.
Attached Thumbnails
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Name:	jensen 990.png
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Attached Files
File Type: asc 990-2.asc (6.7 KB, 1020 views)
File Type: pdf DIY.JE-990.DOA.V1A.pdf (77.7 KB, 1037 views)
File Type: pdf 990.pdf (1.80 MB, 1094 views)
Total Comments 2

Comments

  1. Old Comment
    Steve Hogan and John Hardy posted history of the JE-990 over at -

    Steve Hogan's comments

    John Hardy's comments
    permalink
    Posted 15th June 2015 at 04:38 AM by disfunctionalshadow disfunctionalshadow is offline
  2. Old Comment
    rjm's Avatar
    Thanks for the additional info.
    permalink
    Posted 16th June 2015 at 12:56 AM by rjm rjm is offline
 

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