GSSL HELP THREAD!!!

[gyraf]

David - yes, you have 'stuff missing. Replace with wires

Pat - Note that mounting 5534 reversed will destroy it. Not enough to re-orient, must be replaced. If you already put in new ones, but still no cigar, then check that you have soldered in the wire link at the sidechain insert point, otherwise theres no signal to sidechain, and you won't compress.

/Jakob E.

 

[Script]

Wow. Where you get those boards? (I'd complain for lack of quality control). There's indeed a trace being cut off. Can wire-jump between solder joints.

Attached a partially-populated rev7.

 

[Sisu MT]

David - yes, you have 'stuff missing. Replace with wires

Pat - Note that mounting 5534 reversed will destroy it. Not enough to re-orient, must be replaced. If you already put in new ones, but still no cigar, then check that you have soldered in the wire link at the sidechain insert point, otherwise theres no signal to sidechain, and you won't compress.

/Jakob E.

Thanks Jakob. Anticipated that the 5534s may have been fried, so yes had swapped all of them out. Tried putting in the wire link where the side chain insert point is (assuming these are the two pads that are under a resistor) but unfortunately still not compressing. One observation is that when I turn the threshold knob all the way to the right, the audio cuts out right when the knob hits the rightmost limit. Right before the sound cuts out the VU meter dances a little bit. Any thoughts on where I can troubleshoot next would be greatly appreciated. Thanks!

 

[rikkord]

David - yes, you have 'stuff missing. Replace with wires

Pat - Note that mounting 5534 reversed will destroy it. Not enough to re-orient, must be replaced. If you already put in new ones, but still no cigar, then check that you have soldered in the wire link at the sidechain insert point, otherwise theres no signal to sidechain, and you won't compress.

/Jakob E.

OK, so reportig:
Did the wire replacement for the missing part, which solved the voltage issues. Right now my voltages at
-5534 input opamps are -/+15V on pin 4/7 and the rest is zero
-5532 output opamps are -/+15V on pin 4/8 and the rest is zero or close to zero(0,7 on pin 1/2/6/7)
-5534 dbx emulation circuit opamps are -/+15V on pin 4/7 and the rest is zero
-2181 input vcas are -/+15V on pin 5/7 and the rest is zero or close to zero
-2181 sc vca are -8,2 on pin 5 and 12 on pin 7 so that looks fine aswell (vcas are not in the socket)

So now the distortion problem is gone. Which is nice

Cheking with music and my ears, the compressor circuit works and all the pots and switches (threshold,ratio,attack,release,SC HPF,makeup, compressor on/off) are working.

BUT the left side is not passing audio at all and the meter is not working, so I'm back to some reading and troubleshooting. If I'm stuck or solved the problem I'll let you know. Thanks for your help

 

[rikkord]

OK, so reportig:
Did the wire replacement for the missing part, which solved the voltage issues. Right now my voltages at
-5534 input opamps are -/+15V on pin 4/7 and the rest is zero
-5532 output opamps are -/+15V on pin 4/8 and the rest is zero or close to zero(0,7 on pin 1/2/6/7)
-5534 dbx emulation circuit opamps are -/+15V on pin 4/7 and the rest is zero
-2181 input vcas are -/+15V on pin 5/7 and the rest is zero or close to zero
-2181 sc vca are -8,2 on pin 5 and 12 on pin 7 so that looks fine aswell (vcas are not in the socket)

So now the distortion problem is gone. Which is nice

Cheking with music and my ears, the compressor circuit works and all the pots and switches (threshold,ratio,attack,release,SC HPF,makeup, compressor on/off) are working.

BUT the left side is not passing audio at all and the meter is not working, so I'm back to some reading and troubleshooting. If I'm stuck or solved the problem I'll let you know. Thanks for your help

Ok, so I'm definitely not as sure on this one as on the previous BUT - I followed a constant pink noise through the PCB with measuring AC between 0 and + of input left (the one that is not arriving on the output) and I found that my signal is lost between the 27K(before 2181) and the 15K (after 2181) resistor. First I started to switch the VCA-s to check if maybe the previous issue killed anyo f them, but both works properly on the right channel. So I turned around the PCB and found this. Is there any chance that the leg of the 27K resistor is not connecting to the "route" going to the vca, and this is a similar issue of PCB production as the previous one?

(don't want to blame something I messed up on someone else, but this looks rather curious for me...)

Thanks a lot again

 

[Script]

Not fully sure where you are on the board. If applying some more solder doesn't fix connectivity of trace (use beeper thing on your DMM), check against schematic and overlay. Cut-off resistor leads / legs come in handy for short jumps.

 

[rikkord]

So, just after writing my post I did a continuity check there and as I thought from the schematic and overlay drawing turns out I was right. The circuit does not connect to the ring/plate so it is another production issue with this PCB.

So I inserted a wire and now I have continuity, signal is passing through. Aaaand it sounds right for now.

For the not working meter I'm still looking for the solution, but I'll get there soon hopefully.

What seems strange is how the Threshold reacts. When I'm lowering it and the compression kicks is it is happening right away. But when I'm raising Threshold the level change takes place after a remarkably long time, which is definitely more than what I'd call normal on a buss compressor. Any idea what might cause this, since I haven't run into this issue in the threads?

Thanks a lot

David

 

[gyraf]

in "auto" mode, release can be veeeeery long, if a lot above threshold...

 

[rikkord]

Ok so turns out I forgot the 2K resistor/5k trimpot for the meter) Now it's working, PCB faulties corrected with wire jumpers, everything fully functional. Now some further testing with audio to find out if it is really finished or need some further troubleshooting.

Here's a photo of the inside. Probably will change the sidechain vca socket since it seems a bit loose for the 2181, and have to fix the PCB with the missing nuts.

Empty space for the SSC mod, this is the reason for the 12pos LORLIN for HPF(right now stopped at 2). Thanks for the helpz everyone

 

[Sisu MT]

Thanks Jakob. Anticipated that the 5534s may have been fried, so yes had swapped all of them out. Tried putting in the wire link where the side chain insert point is (assuming these are the two pads that are under a resistor) but unfortunately still not compressing. One observation is that when I turn the threshold knob all the way to the right, the audio cuts out right when the knob hits the rightmost limit. Right before the sound cuts out the VU meter dances a little bit. Any thoughts on where I can troubleshoot next would be greatly appreciated. Thanks!

Can someone please confirm where the side chain insertion point is? I'm trying to complete a basic version without the side chain, Jacob mentioned I need to put a wire link across the side chain insertion point. Are these the three pads where the high pass filter marking is? If so, do I link all three pads together or just two of the three? Thanks, Pat

 

[rikkord]

Can someone please confirm where the side chain insertion point is? I'm trying to complete a basic version without the side chain, Jacob mentioned I need to put a wire link across the side chain insertion point. Are these the three pads where the high pass filter marking is? If so, do I link all three pads together or just two of the three? Thanks, Pat

Hey, I made a picture and marked where the hpf insertion point is. If you don’t install a hpf circuit you connect the two points(1 and 3) where I have the blue and red wire!

 

[Sisu MT]

Hey, I made a picture and marked where the hpf insertion point is. If you don’t install a hpf circuit you connect the two points(1 and 3) where I have the blue and red wire!

Thanks Rikkord. Unfortunately still no compression. Anyone see any obvious issues with the PCB? I'm still wondering if some other components got fried when I installed the 5534's in the VCA backwards (they've been replaced since). I get audio through and makeup gain, just no compression). All voltage test point readings are correct as well.

 

[gyraf]

..what about your control board and bypass switch? (wrong wired bypass is a classic for this)

/Jakob E.

 

[Sisu MT]

Bypass seems to work. First position is bypassed, second position is engaged. When engaged, the make-up gain pot works. here's a pic of the control board. Triple checked the hookup wires between it and the main PCB and they are correct. Checked polarity on all caps and diodes as well. stumped...

 

[Script]

Trace sidechain signal from the 2x47K junction onwards to see where signal disappears.

Or could use this SC troubleshooting guide -- perform measurements ignoring the parts about 'turbo'.
Link is to a post with a comprehensive guide written by member 'SSLtech'.

https://groupdiy.com/threads/turbo-gssl-help-please.28113/post-339348

 

[RAILAUDIO]

Hi guys... i've already done some soldering but i'm a noooooob... : )
i started the gssl project with pcb from pcb grinder..
i ordered the components from the gyraf bom list so i will have to buy some other parts...
-I'm asking you if the 1000 uf/63v, the 100uf/25v and the 22uf/63v radial go well? (for what i know an higher voltage its better right?)
-For the toroidal is it good a 30VA? Talema TRT30215 :: Talema Transformers :: Transformers :: Passive Components :: Electronic Parts :: Banzai Music GmbH
(I'm from italy so we have 220v)
-is it better the That 2181 or the That2180 as VCA?

​

 

[Sisu MT]

Trace sidechain signal from the 2x47K junction onwards to see where signal disappears.

Or could use this SC troubleshooting guide -- perform measurements ignoring the parts about 'turbo'.
Link is to a post with a comprehensive guide written by member 'SSLtech'.

https://groupdiy.com/threads/turbo-gssl-help-please.28113/post-339348

Thanks Script. Started with the troubleshooting guide and got to where the AC reading off pin 7 of the main board TL074 should vary as the thresh hold knob is moved. I got no variation in my reading so something goofed in there. This step not working wasn't addressed in that thread, so I will track the signal on from the 2 47K resistors now as you suggest. Can you please let me know what metric to test for at each point? continuity? Kind regards, Pat

 

[Script]

Yes, power unit off and track for continuity.

 

[Script]

I'd also measure DC around threshold and ratio knobs. When turning, does DC change on wipers? TL072 IC orientation is OK?

 

[Sisu MT]

I'd also measure DC around threshold and ratio knobs. When turning, does DC change on wipers? TL072 IC orientation is OK?

Thanks! will work on this today.