symetrix 525 compressor

I just acquired 2 of these things at a very decent price. They sound ok, but it seems as if somethings holding it back from shining like it could.

I don't know anything about analyzing circuits, so I was wondering if anyone could glance at the schemo's and see if anything stands out that could be done different or better?

symetrix 525 schematics

If so, these can be had for around alesis 3630 money, and they used REAL Neutriks in back!!

I had one of these for a long time before mixing in the box, & I loved it. A real Rock n Roll box, not perticularly quiet but fairly punchy.

A wee bit noisy but a lot of fun.

Peter

I have a coupla' 501 and I really like them. They use a different VCA (2150). What the heck is the VCA in the 525?

I modified mine by changing the opamps to OPA2134 (your U1 and U2) and increasing the output cap(s) (C10 for you) (501 has a balanced o/p so it has two) to about 470uF, if I recall correctly. The box had some low end rolloff that I finally traced out to be due to the value of that o/p cap. I think I would have added 0.1uF film caps across the input caps (your C1 and C2) also.

5532 subbed for the U1 and U2 and the cap changes should clear it up a bit if you want. Beyond that, I would guess that the VCA would be the limiting factor and I don't know what to say 'bout that part.

HTH!!
Charlie

Unfortunately I dont have this box any longer, but if I recall, the VCA has an ECG part number. I did see the schems but did not keep a copy.

Regards
Peter

The schem is a little blurry, I'll have to check the one I have as I think its a little more clear. I think it says "EGC101"

eCg101 comes up as an NPN BJT.

egC101 comes up as a VCA, maybe Valley People? Check this "translated" text from a Japanese website:
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EGC101 at that time the recording console (API and NEVE main current) is produced because it is installed in VCA [hueda], it is the product which extremely competes VCA of the dbx corporation. In addition it was the core part of leading [ehuekuta] Kepex of that time II.
***************

It just gets worse from there...

Aha! Check this thread:
http://www.groupdiy.com/index.php?topic=6787&highlight=egc101

Hope that helps!
Charlie