GSSL HELP THREAD!!!

Sorry for the triple post, I am so excited, I just wanted to say I fixed the problem on that channel being louder than the other (turns out IC chip not pushed in properly somehow)

But everything works beautifully! Oh my goodness I am so freaking happy!

Thank you so much Gustav, Jakob, Udo, and everybody else that helped!
I'm overly joyful right now. First ever project without any electronics and I learned a whole ton!
Oh man!!!!

ONE question though.

I noticed in the release area, the switch that came in gustav's kit has 6 positions but the actual release settings only has 5, when it's at the 6th one the sound is distorting, is that normal? What's that spot supposed to be?

Ave Crux said:

ONE question though.

I noticed in the release area, the switch that came in gustav's kit has 6 positions but the actual release settings only has 5, when it's at the 6th one the sound is distorting, is that normal? What's that spot supposed to be?

Click to expand...

Remove the frontpanel,turn the switch fully ccw (leftmost or 1st position).Remove nut and washer.You should see a metall ring now.Lift it and turn it ccw one postion back,it has a stop pin.Insert and reassemble,done.


Udo.

Ok, still trying to get to the bottom of a gssl w super side chain where the right side stopped working and just hums. It appears to be getting signal in fine as I see the meter working fine so it's likely in the right side output section… Here's where i'm at:

-replaced all op-amps to no avail….
-All power voltages are tested and working fine at regulators.
-I tested voltages on all op-amps and everything appears alright voltage-wise except- pin 1 of one of the output NE5532's(right side one coincidentally) is giving me -14.73 volts which I don't believe is correct. All other voltages on that particular op-amp seem fine and I'm getting the same negative voltage on the NE5532's  pin 4 as I should be. There is no continuity between the -15v rail and pin 1(have checked extensively). I reflowed solder and done everything make sure that area around pin 1 is isolated. Still my meter reads that same negative voltage on that pin… It seems odd to me

I'm kinda stuck here. Would the super side chain cause an issue with an older GSSL board(rev 7)?

So, I finally finished putting together my GSSL kit, from PCB Grinder!  Unfortunately, I missed the mark, somewhere  :-[.  So, upon power up, the gain reduction meter is pinning on max, -20, even with no signal coming in.  I've plugged it into my DAW, and the unit passes the signal, while in bypass mode, but when the compressor is engaged, the signal drops considerably and becomes distorted.  That makes sense, since the meter is showing maximum gain reduction.  Any ideas of where to start, on the troubleshooting?  So close, yet so far away!

dissonantdissident said:

So, I finally finished putting together my GSSL kit, from PCB Grinder!  Unfortunately, I missed the mark, somewhere  :-[ .  So, upon power up, the gain reduction meter is pinning on max, -20, even with no signal coming in.  I've plugged it into my DAW, and the unit passes the signal, while in bypass mode, but when the compressor is engaged, the signal drops considerably and becomes distorted.  That makes sense, since the meter is showing maximum gain reduction.  Any ideas of where to start, on the troubleshooting?  So close, yet so far away!

Click to expand...

Nobody?
O.k.,haven't built it yet,only the meanwhile old version from Jakob a couple of years ago.
I'd start to first check if the issue follows any of the dc controls,so the frontpanel pots and switches.
Do it with some dynamic music,not a sine for now ince you might not see any changes (because it is a static signal).Maybe it is just a short or open condition somewhere.Could be that just the threshold pot is the cause,at least it seems that the circuit does full compression all the time.
So does the issue stay the same while moving the threshold,attack and release controls?
Double check all solders especially on the control board and the multipin connections to the main board.
Same on pots and lorlin switches,check for cold joints.


That's just a first thought,let's see how it works out.


Good luck,


Udo.

dissonantdissident said:

Any ideas of where to start, on the troubleshooting?

Click to expand...

Fixing (except rare occasions) always starts with the power supply. Make sure that all supply rails are operating correctly.
When the unit obviously doesn't operate correctly, you first only connect it to your multimeter, oscilloscope or the like to check voltages going in/out, but not to your daw, a/d, mixer, ... just in order to prevent blowing up connected gear.
From your sidechain related symptoms, by a 99% chance you will fix your GSSL when you get both of the +/-12VDC rails operating. (must have been answered >100 times within the last 50 pages)
The remaining 1% will most likely be unwanted shorts, misplaced components or wrong value parts.

Well, I found another thread, where they mentioned the voltages to look for, at various points.  I got 15v at the inputs, outputs, and VCA sections, at all ICs.  I also got the 12v that I was told to expect, in the sidechain section.  No dice there.  So it looks like the culprit is going to be a short, or misplaced component.  To give folks a clearer idea:

Makeup gain is functional and the sidechain filter both seem to be working.  It is passing audio in both engaged and bypassed positions.  In bypass, there is a little distortion on the peaks of program material, but lower dbs have no apparent distortion.  When engaged, the volume drops, just like the meter indicates, and it gets really crunchy.  I've attached a picture of the main pcb, to see if anyone notices any out of place components. 

Missing wire link on control board, at meter+/- connections?

Otherwise look through this thread for tips on finding and fixing common errors. That is what it's here for.

Jakob E.

If you're talking about the two nearby wires, where they say +/- 15v, then those are definitely in there, and test at the appropriate voltages.  I'm gonna keep plugging through thread, for sure.  If anybody else has any guesses, I'd appreciate them!

Hi guys,

I also managed to complete my GSSL and super-sidechain boards and wired everything up.  But the compressor seems stuck in bypass and the relay doesn't work.

Here's what I tried, checked or found so far:

- the compressor passes audio absolutely fine: no missing low-end, no distortion, left and right channel both have the same volume
- power seems fine - I measured + and - 15V near the VCAs and on the SSC-board input
- the SSC-board sends and receives audio - I checked it with an audio-probe
- the meter-LED pads have no power (!)
- I measured continuity from the bypass-switch
- I reflowed the relay and checked the SSC-board for cold solder joints
- and I searched for similar errors in this thread

I'm still a beginner so any tips or pointers in the right direction would be greatly appreciated!  Have I maybe bought the wrong relay?

Cheers,
Goetz

I would recommend always building and checking the basic GSSL first, and then adding extra boards once you know the basics works as expected.

Otherwise it's very hard to trace errors.

Jakob E.

Hey everyone. I built myself a GSSL a couple of years ago and it works great.
However I recently noticed the threshold changes with the room temperature (I guess). Like, up to +/- 0.7dB or so.
I noticed this as I was running a tone through the comp (say, at -16dBFS) and adjust the threshold so the signal at output was attenuated 4dBs (so it hits -20dBFS in the DAW). Sometimes doing the same operation half an hour later gives another value at the output and I noticed the more the temperature changes, the more "unstable" the threshold is.
I should say that the unit doesn't run particularly hot and has copious space above and under it in the rack.

Anyone noticing the same thing ? Is this normal ? What can I do to make it more stable ?

Thank you very much

Threshold depends only on 78L12 regulation - I don't think it it is supposed to have that large a temperature drift - maybe you are working very close to it's thermal shutdown?

Try another brand 78L12/79L12?

gyraf said:

Threshold depends only on 78L12 regulation - I don't think it it is supposed to have that large a temperature drift - maybe you are working very close to it's thermal shutdown?

Try another brand 78L12/79L12?

Click to expand...

Hi Jakob
Yeah I was very surprised to measure such a large difference in the values (to be fair most of the time the difference is closer to 0.1 to 0.3dB). I measured it because I heard something strange.

I'll try better heat dissipation and eventually another brand of regulators as you suggested and see what happens.

Thanks !

Hi guys,

Ive had my gssl with turbo and crc mods up and running for a long while but i had a problem with powering it up. The first attemp always failed, the meters led lit up but vca's didnt get power and it was not passing audio. The only way to get it to power up was to flick the switch off and the immediately back to on position.

Since this was the only flaw i never got to fix it. Today i started to look whats up. I replaced 7815, installed it off the board to use case as a heatsink. Works perfectly now.

This is for anyone having similar problems. Someone should compilate all the info feom this thread to one FAQ pdf, 

HI
my gssl is finished (made from the new pcb) (with turbo board) and everything works ok on the left side but on the right side the threshold control does nothing and the meter peeks out .. Can some one point me in the right direction regarding the area on the schematic to look at please
Thanks
And yes I have searched this thread for an answer

Darenzo said:

HI
my gssl is finished (made from the new pcb) (with turbo board) and everything works ok on the left side but on the right side the threshold control does nothing and the meter peeks out .. Can some one point me in the right direction regarding the area on the schematic to look at please
Thanks
And yes I have searched this thread for an answer

Click to expand...

Check the orientations of the vca's and that they are well pushed in their sockets if you used sockets. Other IC's too.

Is the bypass wiring correct?

Darenzo said:

HI
my gssl is finished (made from the new pcb) (with turbo board) and everything works ok on the left side but on the right side the threshold control does nothing and the meter peeks out .. Can some one point me in the right direction regarding the area on the schematic to look at please
Thanks
And yes I have searched this thread for an answer

Click to expand...

Hello and welcome to the forum,


as mentioned often before it is not a good idea to modify circuits before having had them up and running in their original condition.Since your issue is related to one side only there is a good chance that it is caused by the modification (the turbo board is a second sidechain).
Best to lift the board temporarily,bring the unit to standard condition and see if the issue is still there.
Otherwise look for the usual things like bad/cold solders,wiring and of course parts orientation.


Good luck,




Udo,

I have been using my unit for years with pleasant results but I do have one strange issue. Every once in a while after I power it on, it will not pass signal, the meter and lights appear to be working as usual but I get no output. If I simply toggle the power switch, it comes back no problem and everything is fine. I'm very tempted to leave well enough alone because it happens quite rarely and it's a quick fix but I would like to figure it out eventually. Any ideas?

A search for "latching" and "regulators" might help,seems to be the issue in your case......


Best,


Udo.