SSL clone, think i fried something

[autocomman]

So after much time of gathering parts and finding time to work on it i got my SSL clone done, but its got issues..ill give u the quick story.  I used audio kitchen PCB's and THAT 2180 VCA'a.  I had 9 pin sockets lying around for the VCA's so i used those.  Simple enough and im always careful about putting things in the right direction, but i dunno where my mind was.  I installed the VCA's 1 pin off and backwards.  Awesome right?  So VCA pin1 went no where, VCA pin 2 was PCB pin 8, VCA pin 3 was PCB pin 7, etc etc.  Only did this with the left and right VCA's, the sidechain was in right.  Either way I replaced all 3, now i got audio, and i have full scale audio in bypass, but when you engage the compressor, the sound is distorted, the meter doesnt work and the compressor isnt compressing.  I have some control with the threshold and makeup gain controls, that about it.  Im thinkin i may have cooked the TL074, maybe the 072...can someone give me some insight as to what I need to check, or where i need to go next?  Thanks!

Mark

 

[abechap024]

the VCA chip might of gotten fried too....try switching the one from the side chain around with the ones in the audio path...I remember my first SSL build I put one VCA in wrong and fried it

 

[autocomman]

I've already replaced all 3 VCA's

 

[ruckus328]

Are you sure the sidechain VCA is oriented correctly?  GSSL boards have a "gotcha" here - There's a "1" in silkscreen at the end of the sidechain VCA, but this does not mean Pin 1, it is actually the silkscreen for a nearby 1nF cap.  This is actually Pin 8 of the VCA (it's orientated the opposite direction of the audio VCA's.

If it is backwards, it likely needs to be replaced (again).  218X VCA's do not like to be oriented backwards, it usually kills the chips, you'd think THAT would put in some sort of protective measure, but guess they sell more VCA's that way  ;D

 

[pucho812]

this should go in the gssl help thread.



Start by testing the PSU and making sure you have proper voltages, then move on from there

 

[autocomman]

Yes, i have the proper voltages, thats the first thing I checked, I have ground + and -15, etc etc. and I referred to the component placement sheets for proper orientation of the VCA's cause ive seen other kits with '1 backwards' component.  I got the sidechain VCA in properly, and all 3 vca's are new and in properly...I have no meter operation either, and I know thats a function of the TL074 thats where im suspect.

 

[elektroivo]

with oscilloscope check all 4 outputs on TL074 (corner legs)

if you don't have scope, just replace that chip... it costs about 1/2 euro

 

[abechap024]

...Either way I replaced all 3...

Oh my bad! Well I would also check your wiring too and from the front panel switch board...those wires are easy to get crossed sometimes.

Its something, and its probably something simple

 

[gyraf]

..please use the official help thread - makes future searches easier.

Jakob E.

 

[autocomman]

Can a mod please move this thread? or should I start a new one...

Im gonna order a new TL074 they are cheep, but iu gotta pay shipping  :-[n  oh well...we will see what happens

Mark