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gyraf

GSSL add-on help thread
« on: February 17, 2017, 03:46:07 AM »
This thread dedicated to all sorts of add-ons and modifications to the GSSL - in order to clean up the original "vanilla" help thread.

Discussion and tracing errors in turbo, sidechains, relay bypass, CRC power cleaning, 202VCA's, etc etc..

Jakob E.
..note to self: don't let Harman run your company..


Re: GSSL add-on help thread
« Reply #1 on: February 17, 2017, 10:43:40 AM »
Thanks, Jakob!

I Searched thru the vanilla GSSL help thread and found one hit from 11 years ago that was somewhat similar but thought I'd ask-

if you want the short version of my question, skip to the bottom :)

I'm modding an existing GSSL with it's own PCB design that includes the turbo mod on it's main board. I wanted sidechain filtering  ability added on. I used more or less the same schematic as this one- http://sounddiy.free.fr/images/SSL/Doc/Sidechain/Sidechain_Sch.pdf

with the exception of leaving out a few of the filters. and I duplicated the circuit since this is a turbo GSSL. The compressor also already has external sidechain ability, so I wired it so that when you engage the external, the existing DPDT relay switches over to the new sidechain filter board.

when I connect the output of the filter board to the main board (at the 47k resistors prior to the VCAs), the unit goes into a strange behavior where the GR shown on the meter reads inversely proportional to the threshold pot setting.

TLDR since this is kind of an oddball in that I didn't build the compressor that I'm troubleshooting, I'd like to know if anyone can shed light on what conditions would have to be in order to make the GR inversely proportional to the threshold setting? Just looking for where to start looking, and I've never built a GSSL before. Sorry if this is a dumb question.

Thanks!

gyraf

Re: GSSL add-on help thread
« Reply #2 on: February 17, 2017, 11:13:04 AM »
..maybe a DC offset at filter output? Should be AC-only...

Jakob E.
..note to self: don't let Harman run your company..