compressor schematic

jhaible jhaible at
Tue Jul 4 01:19:10 CEST 2000

>(Urei, Allison Research, Collins, FAA, GE, WE, etc)

Great site - I didn't know there was so much of this stuff on the web !

>I'd love to hear (read) some words from you about this designs
>(especially the UREI ones), if you dig into them.

Can't say more than "ahh" and "ohh" at the moment. But I'm downloading
like a madman.

Just two remarks for now:

These circuits *do* feature multi stage feedback, even the tube versions.

To expand Magnus' categories of feedforward and feedback, there is the
issue of linear / expo /something else response of the VCA. You only
get constant response times, independent of the momentary level, with
expo VCAs (and log ENV dedectors) if you have a feedback configuration.
That's what *all* these modern compressors (dbx, ssm, you name it)
apparently do.
A LDR doesn't fit in here by nature. It will be interesting to check these
vintage circuits for the courve of the VCA. Do they "linearize" (actually
"expontialize" toe LDR ? Or rather not ?


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