GSSL 6dB difference in stereo level, offset, mismatch. channel 6 dB lower Help!?

[Patch]

Hi guys,

I understand this should be in the GSSL help thread and it is, but having tried searching for this issue I found it hard to find much as the descriptions of the issue is awkward to google/search. So creating another post here too which (hopefully) may help others in the future. Gssl help thread comment/question is here: http://groupdiy.com/index.php?topic=47.7220

Happy Friday guys! Well....not so much for me otherwise I wouldn't be here ahah.

I built my GSSL back in 2008, worked great. I have one turbo board and super sidechain, all working good. Then I changed the VCA to DBX202 Black cans but never got them working perfectly, but useable, So recently I went back to the 2180LC but having gone back I have a problem. The Right channel is about 6dB lower than the Left. I understand this seems due to a + or - on the XLR pins not making connection......but....it doesn't seem to be this...

-Checked voltages everything seems fine, also on all opamp pins.

-Swapped all opamps from left to right / the problem does not swap channels.

-I have bypassed the Left and Right VCAs by jumpering pins 1 to 8 (also stripped all resistors and caps from the 202 emulation circuit) so problem doesn;t seem to be the SC

- Even in bypass the level difference is still there by almost 6dB

-Have replaced all 100uF caps in the output section and all the ceramics and almost all 100nf caps in the output section

-Checked and double checked and traced IN&Out molex connections

-bypassed the board and plugged xlr molex to board connections into each other, the stereo level is perfect so clearly issue is on the board/circuit.

- checked the 15k/27k (have used both) unity gain / VCA input resistors, they are perfect. CHecked the VCA output 15K resistors too, they are also fine.

-I re-tinned all soldering in the input and output section, didn't help.

-I haven't checked/replaced the input section caps yet.

-I haven't replaced the majority of caps in the IN/OUT section yet but it used to work fine and everything I replace on the board doesn't help. My soldering tends to be pretty good so I'm tearing my hair out a bit here.


Does anyone have any suggestions? Any help would be mucho appreciated.

 

[Patch]

Oh I forgot to add that the level mismatch is only from around 40/5- Hz up to 20KHz. If I go lower than 40/50Hz with a noise generator (sine) the audio goes level across the stereo image. Could that be a clue? 

 

[Patch]

Wow group diy is back!!! thank the lord.

Just FYI I resolved the problem. Don;t know what it was but i recapped and 're-resistored' the entire input and output section. It fixed the level, I'm within 0.1 dB  difference generally now. What a royal pain in the ass that was...

 

[rna]

I had a similar problem, ended up being a bad crimp connection on the earth connected to the input xlr's.
Once my unit was working I soldered anything that was crimped just to be sure.