GSSL HELP THREAD!!!

[dissonantdissident]

Well, I must confess that switch wasn't stopping, but I had read about the distortion past auto, so I just wasn't going any further.  Then it occured to me that maybe that one was supposed to be counterclockwise, so I went to the far other end, but it didn't clear up, so I figured clockwise was the right orientation.  I retightened the panel and got it to stop in the right spot, but still getting distortion, when the vca kicks in.  I swapped out the 5532s for some others I had, that I knew worked, but that didn't change anything.  Unfortunately, I don't have any singles, so I haven't been able to change the input and vca circuit opamps.  That being said, when the VCAs aren't engaged, there doesn't seem to be any distortion.  If there is, it's so slight that it's not obvious.  The various switches all seem to be working and the GR meter acts like it's changing it's behavior, with changes to ratio, etc. 

Also, I'm looking through my salvage boards for parts, and haven't found any 5534s, but I did find a board with a lot of LF353N and LF347N chips that I think should work in the TL072/4 slots(in the sidechain), at least for testing to see if those chips are at fault.  Anybody think it's a bad idea to put those chips in there, to test?  Seeing as the gain reduction meter is functioning, I'm leaning towards the VCAs not being the problem.

 

[Mazieresantoine]

rule out the meter by actually running audio thru it and see if it is compressing. If its not compressing with the threshold all the way off or clockwise then it is the meter hookup or the components around the meter circuit.

So i check with sound.
In bypass no pb, ive got the booth channel
In comp mod, it comp in ratio 2 but not change if i turn the threeshold, and no sound in ratio 4 and 10.
I check the connection between main pcb and control pcb and it's all good.
I check the component in the control pcb it's seems ok too.

 

[Mazieresantoine]

And in ratio 4 and 10 the meter stay at 20db comp

 

[Mazieresantoine]

In ratio 4 and 10 there is sound but very very compress
The threshold doesn't work in any ratio the sound is good but very compress in all ratio but the make up is working

 

[Gustav]

In ratio 4 and 10 there is sound but very very compress
The threshold doesn't work in any ratio the sound is good but very compress in all ratio but the make up is working

Could you post a picture of the solder side of your control board?

And did you implement any modifications?

Gustav

 

[Mazieresantoine]

In ratio 4 and 10 there is sound but very very compress
The threshold doesn't work in any ratio the sound is good but very compress in all ratio but the make up is working

Could you post a picture of the solder side of your control board?

And did you implement any modifications?

Gustav

Thanks for your help.
I will post a picture tomorrow.
there's no modificiation, it's your original PCB.

Today i check everything and, i don't know why, it's working.
the only thing i do it's to remove and put again the VCA in the detection circuit.
I compare with one my friend do and it's prety close.
it will run all the night to see what happen.

I come back tomorrow to say if it's good.

Thanks for your help and to be patient with me!

 

[medway]

Hi all, I'm a current owner of a GSSL that has a fault and looking for any ideas on what it could be. I purchased this from a studio years ago so haven't constructed it myself.

What's happening basically is that the gain reduction just started randomly increasing today. I've ruled out the material being the culprit by testing with just a sine tone.

I can be fine for a minute or so and then for 10 seconds or more the GR just pops up about 10-20db higher than it should. It will stay that way anywhere from a few seconds to much longer before eventually settling down again.


My second question is that the unit I've got is housed in a 3U rack space with holes already drilled on the other side as the previous owner had dual compressors in one rack. He took the right side one out when I purchased it.

There is a switch under the level meter that allows it to read either side.

Do I need a second transformer to install a second unit inside or is it possible to tap off the existing one?

Cheers

 

[Mazieresantoine]

In ratio 4 and 10 there is sound but very very compress
The threshold doesn't work in any ratio the sound is good but very compress in all ratio but the make up is working

Could you post a picture of the solder side of your control board?

And did you implement any modifications?

Gustav

I Gustav, here it's my soldier side for your project.

i can send you by mail if you want.

it run 2 hours with no problem, then it have the same problem (sound very low, seems like very  very compress), and we don't why it come back and run correctly.

 

[Mazieresantoine]

another one

 

[Mazieresantoine]

last one

 

[Gustav]

last one

1. You wrote "no modifications", but I see a SC board installed. Take that out of the equation, so we can focus on the basic operation of the unit..

2. If your boards landed on my bench, the first thing I would do is start reflowing the solderpoints from one end.

Did you do the main board first, then the control board? Seems like the control board is better, so you may have gotten the hang of it during your work. Apply that now.

There are many suspect and cold solder points, and I am not surprised if connections vary with the phases of the moon. Even if it did work, it is not a unit you can trust to keep working as it is.

Gustav

 

[Gustav]

Hi all, I'm a current owner of a GSSL that has a fault and looking for any ideas on what it could be. I purchased this from a studio years ago so haven't constructed it myself.

What's happening basically is that the gain reduction just started randomly increasing today. I've ruled out the material being the culprit by testing with just a sine tone.

I can be fine for a minute or so and then for 10 seconds or more the GR just pops up about 10-20db higher than it should. It will stay that way anywhere from a few seconds to much longer before eventually settling down again.

Im not smart enough to pin point this exactly, and I am not 100% sure what you mean by "GR pops up about 10-20dB higher than it should". but I would check the behaviour of the regulated 12V supplies during this to start the troubleshooting problems with random drift in GR and threshold settings. Maybe the transformer was swapped to something unable to provide you with sufficient current when the unit was split? Cant hurt to check these things.

It would also be nice to know if this only happens to the meter read-out, or if it affects the audio, since you describe an alternative meter set-up.  (I can't make it out from your post)

My second question is that the unit I've got is housed in a 3U rack space with holes already drilled on the other side as the previous owner had dual compressors in one rack. He took the right side one out when I purchased it.

There is a switch under the level meter that allows it to read either side.

Do I need a second transformer to install a second unit inside or is it possible to tap off the existing one?

Cheers

Depends. what is the rating of the existing transformer?

Gustav

 

[Mazieresantoine]

last one

1. You wrote "no modifications", but I see a SC board installed. Take that out of the equation, so we can focus on the basic operation of the unit..

2. If your boards landed on my bench, the first thing I would do is start reflowing the solderpoints from one end.

Did you do the main board first, then the control board? Seems like the control board is better, so you may have gotten the hang of it during your work. Apply that now.

There are many suspect and cold solder points, and I am not surprised if connections vary with the phases of the moon. Even if it did work, it is not a unit you can trust to keep working as it is.

Gustav

Thanks for your response.

Yes there is a SC card in the case but it's not wired on the GSSL.
For the moment, my GSSL is in the basic mod.

And yes I did the control board after the main board.
I will do again the soldier point of the main board, maybe the detection section first, because the audio work in bypass.

Thanks for your help again.
I will do it the week and come back with, I hope, some good news!

 

[ding]

Please don't take this the wrong way, I'm in no way trying to discourage you. If I were you though I would get a good solder practice kit and go at it for a week. Then I would try my hand at a few guitar pedals. Those solder joints look very suspect.  Please don't feel like I am trying to be rude. I am just trying to help. Good solder skills will help you tremendously in your future DIY endeavors. Good luck. DIY is very rewarding. Also check and make sure solder joints that are not supossed to be touching are not touching and look out for cold solder joints.

 

[Mazieresantoine]

Please don't take this the wrong way, I'm in no way trying to discourage you. If I were you though I would get a good solder practice kit and go at it for a week. Then I would try my hand at a few guitar pedals. Those solder joints look very suspect.  Please don't feel like I am trying to be rude. I am just trying to help. Good solder skills will help you tremendously in your future DIY endeavors. Good luck. DIY is very rewarding. Also check and make sure solder joints that are not supossed to be touching are not touching and look out for cold solder joints.

Don't worry, you don(t discourage me!
I will check and do again my soldier point.
I checked that there is no touching point but i will do my solder again and see if i's working (what i think) after that.

Thanks for your help

 

[medway]

Hi all, I'm a current owner of a GSSL that has a fault and looking for any ideas on what it could be. I purchased this from a studio years ago so haven't constructed it myself.

What's happening basically is that the gain reduction just started randomly increasing today. I've ruled out the material being the culprit by testing with just a sine tone.

I can be fine for a minute or so and then for 10 seconds or more the GR just pops up about 10-20db higher than it should. It will stay that way anywhere from a few seconds to much longer before eventually settling down again.

Im not smart enough to pin point this exactly, and I am not 100% sure what you mean by "GR pops up about 10-20dB higher than it should". but I would check the behaviour of the regulated 12V supplies during this to start the troubleshooting problems with random drift in GR and threshold settings. Maybe the transformer was swapped to something unable to provide you with sufficient current when the unit was split? Cant hurt to check these things.

It would also be nice to know if this only happens to the meter read-out, or if it affects the audio, since you describe an alternative meter set-up.  (I can't make it out from your post)

My second question is that the unit I've got is housed in a 3U rack space with holes already drilled on the other side as the previous owner had dual compressors in one rack. He took the right side one out when I purchased it.

There is a switch under the level meter that allows it to read either side.

Do I need a second transformer to install a second unit inside or is it possible to tap off the existing one?

Cheers

Depends. what is the rating of the existing transformer?

Gustav

Hi Gustav, thanks for taking the time to reply and sorry if a few things weren't clear.

What I mean about the GR popping up is that say I have a sine tone running through it generating 3db of GR, it will be steady and then all of a sudden the GR will increase to say 15db, it will maintain that for some period of time before usually dropping back to where it should be.

I have monitored the behaviour using an RMS meter in my DAW and will also notice much smaller fluctuations for even just a few db but it can also go as high as making the GR meter fully pegged in some instances.

And yes this is actually affecting the audio, it's not just a metering issue unfortunately.

For the alternative meter what I meant is that there is a single meter on the unit but there is a switch under it which lets it show the signal from either Compressor A or B. Currently I only have a single compressor in this case so it stays on A.

Once a second unit is installed (like how it was before the B compressor was removed before sale) I can then use a single meter to show either compressor.


Regarding my second question I'll have to take the unit apart first to check the rating of the transformer. Sounds like it's probably better to just purchase a standalone one if I want a second unit inside this case and just share the power switch.

Thanks again.

 

[totemst]

Hi, all. I have a problem with my GSSL. I build it few month ago with THAT2181 VCA's. The only mod i have done is a relay bypass. Relay powers exactly like in Jackob's schematics.The compressor sounded great and everything was OK until i changed the VCA's to 202xt. It was interesting to hear the difference. Now it's really loud buzz when compressor works. It passes audio and compresses, but its too noisy. Buzz level and audio level changes with makeup rotation. I disconnect relay board from inputs and outputs - no changes. Buzz is much louder when relays are powered. It seems like power supply or grounding issue. Any ideas? Sorry for my english. :'(

 

[Harpo]

Relay powers exactly like in Jackob's schematics.

there is no relay in the original GSSL schematic, so powering of the relay coil(s?) will require some more current at whatever voltage these coils might operate. Flyback diodes are installed ?

...until i changed the VCA's to 202xt.

...requiring more than 10 times (typ.26mA) the current of previously installed THAT2181s (typ.2.4mA) per VCA, next to different values of input resistors in front of your 202XTs and feedback resistors in the VCA following I2V stage, ... for a comparable result.
You are aware of the possible difference between '202XT VCA's and 'known working 202XT VCA's ?
The type of illumination  (LED/light bulb) in a single status display or GR-meter might draw more current than the complete GSSL. Anything shining built in your unit ?
Can your power supply deliver the required amount of voltage and current ?

Sorry for my english

mine is probably worse. Please update your profile with your location data. Not only mains voltages differ a lot between different continents/countries.

 

[totemst]

Relay powers exactly like in Jackob's schematics.

there is no relay in the original GSSL schematic, so powering of the relay coil(s?) will require some more current at whatever voltage these coils might operate. Flyback diodes are installed ?

There is additional 7812 in the schematics to power optional releys and lights. Relays are pair ofPanasonic DS2E-S-DC12V with 17mA coil current (2x17=34mA total)
http://ru.farnell.com/panasonic-electric-works/ds2e-s-dc12v/relay-dpdt-12vdc-3a-tht/dp/4389931
Relays powered by additional 78L12, no flyback diodes.

 

[totemst]

...requiring more than 10 times (typ.26mA) the current of previously installed THAT2181s (typ.2.4mA) per VCA, next to different values of input resistors in front of your 202XTs and feedback resistors in the VCA following I2V stage, ... for a comparable result.
You are aware of the possible difference between '202XT VCA's and 'known working 202XT VCA's ?
The type of illumination  (LED/light bulb) in a single status display or GR-meter might draw more current than the complete GSSL. Anything shining built in your unit ?
Can your power supply deliver the required amount of voltage and current ?

Power transformer is 15VA, 2 X 15V
http://ru.farnell.com/multicomp/mcfe015-15/transformer-15va-2-x-15v/dp/9531670
No GR meter. Power "ON" indicator is a common red LED. I try to use more powerful transformer(2x18v, 750mA) with the same result. So, power supply should be OK.
The 202s is from old dbx de-essers, so it's no garantee...
And what is the possible difference between the 202xt's?