GSSL HELP THREAD!!!

[salomonander]

thanks weiss,
well i have some issues with unity gain due to adding a cavendish board. but that should not matter now as im running on ics atm.
there are two other things that seem dubious to me:

the ratio: when feeding a low to moderate level input 2:1 always does more reduction that 10:1. at some point (level) this flips and 10:1 actually show the most compression. reading through this thread is a pain. but from what i gathered this might be normal?

threshold: the way this sits atm i can get barely any compression when feeding a 0db sinus (as needed for meter calibration). i certainly can't get 10db of compression. there is a resistor on the control board (47k*) that supposedly reduces threshold sense. maybe jumper that?

cheers

 

[weiss]

Opinions vary, but I can see at least 4 wrong resistor values in the VCA substitution blocks (the 3K9's current setting resistors for the +/-15V supplied VCAs would better be 5K1. The 68R's for the DBX2150 type VCAs should be removed/left out for your THAT2180 type VCAs.)
You -in this order- removed the nut, the washer and the indexing ring below the nut, turned the rotary switch full CCW and put back the indexing ring to the full CW position 5 for the release switch?

i changed the resistor values and reset the release switch but the release still has very little effect on the signal...
Where could i look further?

thanks for your help guys

the ratio: when feeding a low to moderate level input 2:1 always does more reduction that 10:1. at some point (level) this flips and 10:1 actually show the most compression. reading through this thread is a pain. but from what i gathered this might be normal?

yes you got to readjust the threshold when switching ratios, this is my experience as well. when i switch from 2:1 to 10:1 i need to lower the threshold otherwise, it is doing no compression. is that what you asked?

threshold: the way this sits atm i can get barely any compression when feeding a 0db sinus (as needed for meter calibration). i certainly can't get 10db of compression. there is a resistor on the control board (47k*) that supposedly reduces threshold sense. maybe jumper that?

you could try that, but i would also check for some other wiring / populating errors, as i doubt, this will have that great impact on the overall sensitivity.

 

[weiss]

Could anyone tell my why I. Can’t defeat the makeup? I completely rewired the bypass switch. What could be the issue?

 

[Potato Cakes]

Could anyone tell my why I. Can’t defeat the makeup? I completely rewired the bypass switch. What could be the issue?

The two solder pads shown as black dots next two the 750k resistor have to be shorted when bypassed for make up gain defeat. So however you wire your bypass switch these two pads must make a connection together some how.

Thanks!

Paul

 

[weiss]

The two solder pads shown as black dots next two the 750k resistor have to be shorted when bypassed for make up gain defeat. So however you wire your bypass switch these two pads must make a connection together some how.

Thanks!

Paul

Thanks Paul,

This is mysterious. I can’t see any connection. Gotta Check continuity later.
Do i need to remove the resistor like in the picture as well?

 

[Potato Cakes]

The resistor that it says to remove is the 1k for the power LED if you just use toggle switches. If you use LED push buttons you would use 1k resistor on each button's LED and not on the ratio board.

The connections on the board are unmarked but they are next to the make up gain pot connections as you can see. However you are doing your switching, whether it is toggle or relay or push button, one set of poles somewhere has to make that connection between those two pads when you bypass the compressor. You may even have to add a relay or a switch with more poles to do this. But that is how you do make up gain defeat for the GSSL unless you add a hardwire bypass on all of the XLRs.

Thanks!

Paul

 

[weiss]

The resistor that it says to remove is the 1k for the power LED if you just use toggle switches. If you use LED push buttons you would use 1k resistor on each button's LED and not on the ratio board.

The connections on the board are unmarked but they are next to the make up gain pot connections as you can see. However you are doing your switching, whether it is toggle or relay or push button, one set of poles somewhere has to make that connection between those two pads when you bypass the compressor. You may even have to add a relay or a switch with more poles to do this. But that is how you do make up gain defeat for the GSSL unless you add a hardwire bypass on all of the XLRs.

Again thank you, paul.
I checked for continuity at the pads and noticed something weird.
When i check between both pads i can break the connection with the switch, but when i check between the pads and the middle leg of the makeup potentiometer there is always continuity which explains my problem! but there is no connection between the potentiometer and the pads.... is the pot broken? or the switch? what am i missing ???

 

[weiss]

Now i replaced the whole control board and the makeup gain works correctly. I don't know what the problem was. Am gonna trash the old board...

thanks for your help!

 

[weiss]

i want to avoid the super sidechain board and use a rotary switch to use different frequencies for the hpf like in this picture:

Is it correct that i combine the two 47k resistors, connect this to my SW pole and then on each lug connect the corresponding cap and wire it to the other end of the 47k resistors?

any help would be appreciated.

thanks

 

[Harpo]

Is it correct that i combine the two 47k resistors, connect this to my SW pole and then on each lug connect the corresponding cap and wire it to the other end of the 47k resistors?

No. (this would make it a mono compressor with fighting left/right side).
Your switched caps ensemble connects between TL074/pin7 (the output of the current to voltage converter) and the following DC-blocking 22uF/35V cap. This further goes to the two 20k input resistors of the full wave rectifier, each connecting to a virtual ground node, so the resistive part of the -6dB slope R/C HPF is the paralleled value of these=10K.  The HPF cutoff point is set by 1/(2xPI() x R x C) with R in Ohms and C in Farad. Keep in mind, this is NOT an external input as this would be breaking the sidechain-VCA/rectifier/timing control-loop.

 

[weiss]

No. (this would make it a mono compressor with fighting left/right side).
Your switched caps ensemble connects between TL074/pin7 (the output of the current to voltage converter) and the following DC-blocking 22uF/35V cap. This further goes to the two 20k input resistors of the full wave rectifier, each connecting to a virtual ground node, so the resistive part of the -6dB slope R/C HPF is the paralleled value of these=10K.  The HPF cutoff point is set by 1/(2xPI() x R x C) with R in Ohms and C in Farad. Keep in mind, this is NOT an external input as this would be breaking the sidechain-VCA/rectifier/timing control-loop.

harpo! you are the man ! this works like a charm. i tried it between the resistors before but the effect wasn't pleasant.
Now this thing is absolutely perfect. thank you very much! 

 

[VerreyckenGerd]

Hi all,

Build myself one of those Gyraff Audio GSSL comps.
Everyhging works within a certain range of the settings but the unit behaves bad @ higher copression.

When I turn the threshold down slowly and I receive more and more compression @ a certain level (around 10db) of compression the needle jumps all the way to maximum compression and the unit goes silent for a brief moment. Then the sound returns @ the speed set by the release.

Every control element on the panel works but once I hit a certain amount of compression the thing goes TILT.

On a typical drum loop this happens every 2 snaredrums or so.

Any ideas?

Thanks in advance.

 

[weiss]

Hi all,

Build myself one of those Gyraff Audio GSSL comps.
Everyhging works within a certain range of the settings but the unit behaves bad @ higher copression.

When I turn the threshold down slowly and I receive more and more compression @ a certain level (around 10db) of compression the needle jumps all the way to maximum compression and the unit goes silent for a brief moment. Then the sound returns @ the speed set by the release.

Every control element on the panel works but once I hit a certain amount of compression the thing goes TILT.

On a typical drum loop this happens every 2 snaredrums or so.

Any ideas?

Thanks in advance.

I had a similar problem with one of my units. Did you check voltages? What VCA's are you using?

 

[Potato Cakes]

Hi all,

Build myself one of those Gyraff Audio GSSL comps.
Everyhging works within a certain range of the settings but the unit behaves bad @ higher copression.

When I turn the threshold down slowly and I receive more and more compression @ a certain level (around 10db) of compression the needle jumps all the way to maximum compression and the unit goes silent for a brief moment. Then the sound returns @ the speed set by the release.

Every control element on the panel works but once I hit a certain amount of compression the thing goes TILT.

On a typical drum loop this happens every 2 snaredrums or so.

Any ideas?

Thanks in advance.

Double check your components and solder joints, especially on and around the header that connects to the control board. Also check the wiring from the main PCB to the control board. My first GSSL had a pair of wires crossed there and a solder bridge on that header which caused it to malfunction.

Thanks!

Paul

 

[VerreyckenGerd]

I had a similar problem with one of my units. Did you check voltages? What VCA's are you using?

Coolaudio V2181's. I did check powerrail voltages on all IC's. They are OK. I didn't check signal voltages. Didn't find good references for them yet.

 

[weiss]

Ok. Then first thing I would check is solder points especially the 10 pin connector, source of most problems.

 

[juliusbusch]

Hey guys.
I got a problem which i can not solve. I've been troubleshooting the electronics and searching in this thread for days, but one error remains.
After fixing a not responding threshold, my ratio, attack and release are still behaving badly.
The amount of compression comparing 2: and 4: feels really big, but between 4: and 10: , there is nearly any difference. I checked all components on the control pcb (rev#7) and everything is fine. I checked every solder point on both pcbs for shorts to the surrounding ones and changed all ICs. Supply voltage is at -11,78V and +12,22V. The audio channels are working fine.

Can anyone help me? (Sorry for the grammar)

 

[Gustav]

comparing 2: and 4: feels really big, but between 4: and 10: , there is nearly any difference.

You may simply be throw off by the fact that the threshold is switched with the ratio, so try getting some objective measure on it (measuring the actual ratio).

Gustav

 

[weiss]

Hey guys,

I continued working on a gssl with distortion problems. Pulled the main pcb from a working unit, replaced it and the problem persisted: instead of the expected compression, distortion is coming when turning the threshold down. The moment i turn bypass off (compressor active) the meter jumps to the middle of the scale. When bypass on it goes back to the left ???

The only thing i didn't replace was the control board. I resoldered the 10 pin connector, potentiometers and checked for continuity (as i had problems with lifted pads on this pcb). Found nothing that would explain it so far.

I read that switches which weren't soldered on the pcb could be a problem. Is there a way to rule that out? I'd really want to avoid resoldering all the switches. Note: i removed them from the front panel, turned them fully CCW and set the stop position back in, so that can't be it!

thanks in advance!
Ansgar

 

[weiss]

I resoldered the control board connections and now the meter doesn't move anymore to the middle when the compressor is engaged, but it moves a little away from  zero depending how much I turn makeup ??? But the distortion is still there. Already looked for shorts. I‘m gonna replace the switches next. Or does somebody have another idea?!?

UPDATE: Problem solved. I resoldered the 10 pin connector a third time, there must have been a faulty contact or something. And another thing i found out, the connections from the off board mounted rotary switches were soldered mirrored. That's why there was distorted sound. Either way it seemed to work, that's what i don't understand.
But i got it fixed now  !