GSSL HELP THREAD!!!

[catosalsa]

Hello!
I finished building the gssl, but it doesn't work.
I found that the -15v rail is -5.8v. I measured it without OPamps and VCAs. Or am I measuring it the wrong way? (black probe on 0v/chassi?). I changed the 7915 regulator as I thought it was broken, but it's still the same problem. Where should I start looking?Thanks!

 

[weiss]

Hello!
I finished building the gssl, but it doesn't work.
I found that the -15v rail is -5.8v. I measured it without OPamps and VCAs. Or am I measuring it the wrong way? (black probe on 0v/chassi?). I changed the 7915 regulator as I thought it was broken, but it's still the same problem. Where should I start looking?Thanks!

Hello catosalsa!

First i'd suggest to check the voltages coming from the transformer (2x AC). What transformer did you use? Connect it correctly?

What is the voltage after the bridge rectifier?
You should read +/-15V, +/-12V at the voltage regulators and at all IC's

you'll get there!

 

[catosalsa]

Hello catosalsa!

First i'd suggest to check the voltages coming from the transformer (2x AC). What transformer did you use? Connect it correctly?

What is the voltage after the bridge rectifier?
You should read +/-15V, +/-12V at the voltage regulators and at all IC's

you'll get there!

Thanks! The bridge rectifier was find. Found out the 10R resistor after was bad. Replaced and now I've got audio. The make up gain pot works, but no compression. Will have a look at this later.

 

[catosalsa]

you'll get there!

Thanks!

I've checked everything I can think of (and know how to) now, still no compression. I was thinking that maybe the VCAs got broken for the same reason the R10 on the - rail after the rectifier and the -15V regulator (two components I found wasn't working)? How can I check if the VCAs (THAT2180) is still alright or not? I measured voltages on the VCAs:

On sockets without VCA installed:
Pin5: -15V (-7.9V on side chain VCA)
Pin7: 15V (12V on side chain VCA)

With VCA installed:
Pin5: -2.9V (on all three VCAs)
Pin7:15V (12V on side chain VCA)

 

[gyraf]

figures look right.

And having makeupgain working is good.

Have you remembered the wire link at the sidechain-insert-point..? Double-check bypass wireing (one part of this breaks sidechain signal, the other makeup gain)..?

Jakob E.

 

[catosalsa]

Have you remembered the wire link at the sidechain-insert-point..? Double-check bypass wireing (one part of this breaks sidechain signal, the other makeup gain)..?

I have these wires installed, if you mean the wires at HPF on the board to the capped switch? 
Make up gain bypassing works. I double checked the bypass switch wires yesterday, and tested continuity between board solder point to switch and didn't find any issues there. I can check again och and have a second look at the soldering on the the bypass switch later this week when back home. Thanks for your help!

 

[Farmboy presents]

Hi, I am at the exact same place as you.  Audio passes, makeup gain works but no compression.  My voltages at the VCAs measure the same as yours too.  I am interested if you have any progress.

 

[Gustav]

Hi, I am at the exact same place as you.  Audio passes, makeup gain works but no compression.  My voltages at the VCAs measure the same as yours too.  I am interested if you have any progress.

Like Jakob asked two posts back, did you use or jump the sidechain aux point?

Installed any mods?

Gustav

 

[Farmboy presents]

I have these wires installed, if you mean the wires at HPF on the board to the capped switch? 
Make up gain bypassing works. I double checked the bypass switch wires yesterday, and tested continuity between board solder point to switch and didn't find any issues there. I can check again och and have a second look at the soldering on the the bypass switch later this week when back home. Thanks for your help!

It Works!!!! All of it!!
The problem was a wire to the control PCB was not soldered at the main board end.  I thought it was the diode between the rectified sidechain and the ratio knob but when I looked really close: there was a bare wire poking through.  and I was sure I had looked at EVERY solder point at least five times.

 

[Gustav]

It Works!!!! All of it!!
The problem was a wire to the control PCB was not soldered at the main board end.  I thought it was the diode between the rectified sidechain and the ratio knob but when I looked really close: there was a bare wire poking through.  and I was sure I had looked at EVERY solder point at least five times.

Nice!

Gustav

 

[weiss]

It Works!!!! All of it!!

glad you solved it!

 

[catosalsa]

figures look right.

And having makeupgain working is good.

Have you remembered the wire link at the sidechain-insert-point..? Double-check bypass wireing (one part of this breaks sidechain signal, the other makeup gain)..?

Jakob E.

i've double checked the bypass wires now, and at the side chain insert. Everything is as it should, i followed the gssl build guide. Make up gain works as I wrote earlier, but there is no compression. Even if I think the bypass- and sidechain switch is right, should I skip them? Can I do that, jumper so the compressor is always on. Just to be 100% it's not the bypass switch that is my problem?

 

[gyraf]

You have the +-12V for the sidechain?

Check wireing between frontpanel and pcb?

Jakob E.

 

[catosalsa]

You have the +-12V for the sidechain?

Check wireing between frontpanel and pcb?

Jakob E.

I checked the all wires yesterday.
I have +12V allright. I looked for -12V and found at following places:
- one end of the 3k9 resistor (the other end -2.87V)
- at one end of the 220k resistor (other end 0V)
-pin 4 at TL072
- 11 at TL074

 

[Thunbo]

It Works!!!! All of it!!
The problem was a wire to the control PCB was not soldered at the main board end.  I thought it was the diode between the rectified sidechain and the ratio knob but when I looked really close: there was a bare wire poking through.  and I was sure I had looked at EVERY solder point at least five times.

Hi Farmboy presents
Which wire did you change?
Have the exact same phenomenon.

 

[Thunbo]

I finally got mine to work this morning!

First i tried switching the cableway from 220k r> Threshold Pod. So outside the F road from main to control board. A direct cable from 220k r to the mid pin of the 50k lin pod.

Then I changed the + road, from the jumber by the sidechain to the 620k r.

..Still no changes. Still no compression.

Then I put a jumper over the 47k r, and now it seems to compress just fine.
I will test on and see if everything is as it should be. But for now everything looks just fine.

 

[YesYes]

Hallo.

I just bought a GSSL (PCB Rev 7), that has a problem. After some time on and it's compressing, it shots down for the compressor part, but the sound will continue, just uncompressed. Right after it shots down, i can turn it on immediately, but after 1 min it will shot down again. Like something is getting overheated.

I checked the components to see if something was getting warm, and the 78l12 was very hot. I then checked the V over 78l12 and it was 22V. In my head it should be 15V, that will come from the 7815.

I don't know if that is the problem, or what i should do to solve it, hope you guys can help.

Thanks.

 

[gyraf]

If 78L12 gets too hot and shuts down, you loose compressoon. We have had that error earlier in this thread.

Usually because too much 12V power is used for light or such



Jakob E

 

[cray]

Hello .
One question please.

im doing the shopping for a Gssl
its possible to fit 1000UF 50V instead( 63v) ?

thank you!

 

[gyraf]

yes, psu capacitors here just require working voltage of 35V or higher...

Jakob E.