GSSL HELP THREAD!!!

[ltn.koerschgen]

Hi Guys,
have some Super Sidechain PCBs wich I purchased some 15 years ago... Its the J. Backhaus Rev A version. Searched the forum for some hours, but I couldn't find a working link to get access to the Bom.
Does anyone have any info for this particular PCB? There are not Values on the Board, just references to the parts.
Thanks in advance!
Happy eastern,
K

 

[atticus1872]

WE HAVE COMPRESSION!!!! sweet crushing compression (-; Sure enough it was an incorrect resistor value. Turns out the orange on the 4 band of the 510K resistor was very brown looking which is why my earlier double checking passed over it. ugh! Anyway, audio is clearly compressing and meter is dancing like gem! Thanks so much Jakob @gyraf and @Script for your generous support helping newbs like me learn and improve our skills. So fun! I'm going to make sure everything is working as it should...then on to turbo mod and sidechain! (-;

Totally random and unrelated but where did you find your side chain and power button? That’s a collective case panel correct? I’ve been looking for said switches. Let me know thanks! Also congrats on your build!

 

[rapidcore]

Hello Guys.
something strange happen with my GSSL. When I connect gain reduction meter , make up stops working (signal is a bit lower and a bit distorted). Gain reduction meter reacts for make up gain, but it doesn't impact for signal.
I have 'classic db meter' - 1mA , 100Ohm, 0-20db scale.
Without meter, make up works (but not sure if 100% correct - it starts make up volume from 2/3 way of rotation)
Main board is rev7 - compression works
Control board compressor adjustments seems to work correct (attack, ratio etc.)
I didn' find similar problem on forum.
What can be wrong?
As I understood - meter connection is control board 'Meter +- ' , above control board 10pin connector?

 

[Clbraddock]

Anyone have the pdf bom from here:

http://members.cox.net/capstanrecording/SSLCloneParts.pdf
It’s linked in the meta, but the site is dead/gone :-(

 

[ivan]

Anyone have the pdf bom from here:

http://members.cox.net/capstanrecording/SSLCloneParts.pdf
It’s linked in the meta, but the site is dead/gone :-(

https://web.archive.org/web/20110104190159/http://members.cox.net/capstanrecording/SSLCloneParts.pdf

 

[Clbraddock]

https://web.archive.org/web/20110104190159/http://members.cox.net/capstanrecording/SSLCloneParts.pdf

Duh. Why do I always forget that. Thanks!

 

[rapidcore]

Hello Guys.
something strange happen with my GSSL. When I connect gain reduction meter , make up stops working (signal is a bit lower and a bit distorted). Gain reduction meter reacts for make up gain, but it doesn't impact for signal.
I have 'classic db meter' - 1mA , 100Ohm, 0-20db scale.
Without meter, make up works (but not sure if 100% correct - it starts make up volume from 2/3 way of rotation)
Main board is rev7 - compression works
Control board compressor adjustments seems to work correct (attack, ratio etc.)
I didn' find similar problem on forum.
What can be wrong?
As I understood - meter connection is control board 'Meter +- ' , above control board 10pin connector?

Problem Fixed.
It was caused by 10pin connector cable . I used 10 wires flat ribbon cable to connect mainboard with control board. As I described previously, everything was working until connect meter. It looks like ribbon cable which I used, was too weak ( poor quality? ). Investigation was difficult because multimeter continuity tests were passed. I replaced that cable , as 'peak' of my frustration (after check many other elements).
Lessons learned:
Make sure to use good quality connector components. Lots of cheap quality products in the shops

 

[joshk34]

Using DBX202 VCA's (never seen these with lables attached in opposite directions), to what value resistors did you change in order to adapt for the lesser allowed input current (the 27k voltage to current converters in front of the VCAs are now FI 100k..?), the corresponding feedback resistors in the VCAs following I2V converters (the 15k now are FI 50k with paralleled compensation caps 100pF decreased to FI 33pF...?), the VCAs different control law -50mV/dB for the DBX202C from GSSL-schematic (missing the appendix 'C') vs. -6mV/dB for the DBX202 is adapted by...?, just to name a few...

Thanks for the reply, sorry for the delay in getting back, just had my first kid, so been a bit distracted. Here's what I changed, from what I could glean from my internet research, schematic, etc. I'm still learning so I might have misread or missed something. So this is kinda where I'm stuck at the moment.

 

[joshk34]

Sorry to bump, trying to finish this up with what little free time I have. Could be my sleep addled mind, but haven't been able to make any progress this week with more testing and research. Any insights?

 

[rikkord]

Hey guys, I haven't found a tottally similar case so here's what happened: I had a properly working gssl unit for quite a few months for now. Out of nowhere right signal passing thorugh became almost minus infinity lower. So opened it up, first measured the voltages on the 5532,5534,tl072,tl074 and the vcas. All good, proper values. Then I went on the transformer side just to make sure and the input of the 7815 and 7915 and also on the 7812 is 21-22v. Although the output and the ground is fine. could this 22v input voltage causing this? Since the output is fine on the voltage regulators and the voltage values on the ICs are fine they shouldn't be fried I suppose? Maybe the bridge rectifier is dead or something with the 1000uF capacitors or that two resistors? As far as i know there is nothing else inbetween the transformer and the voltage regulators. Also transofmer measured, seemed fine.

Thanks
David

 

[timtom]

Hey guys, I haven't found a tottally similar case so here's what happened: I had a properly working gssl unit for quite a few months for now. Out of nowhere right signal passing thorugh became almost minus infinity lower. So opened it up, first measured the voltages on the 5532,5534,tl072,tl074 and the vcas. All good, proper values. Then I went on the transformer side just to make sure and the input of the 7815 and 7915 and also on the 7812 is 21-22v. Although the output and the ground is fine. could this 22v input voltage causing this? Since the output is fine on the voltage regulators and the voltage values on the ICs are fine they shouldn't be fried I suppose? Maybe the bridge rectifier is dead or something with the 1000uF capacitors or that two resistors? As far as i know there is nothing else inbetween the transformer and the voltage regulators. Also transofmer measured, seemed fine.

Thanks
David

What kind of transformer are you using?

 

[rikkord]

I use a Triad VPT30-830.

 

[Harpo]

Sorry to bump, trying to finish this up with what little free time I have. Could be my sleep addled mind, but haven't been able to make any progress this week with more testing and research. Any insights?

Maybe start with two VCAs, not with a VCA and a RMS detector (the upper one seems to be a DBX 207)...

 

[joshk34]

Maybe start with two VCAs, not with a VCA and a RMS detector (the upper one seems to be a DBX 207)...

I think that's just the resolution on the picture, they both say 202 on them. Unless of course, I'm missing something.

 

[rikkord]

Ok, so I decided to swap VCA's to see maybe one of them is dead (hopefully unrelated to the voltage regulater input leg 21-22V issue - since the outputvoltages are fine I supposed that maybe the "no audio passing channel" is unrelated. And then stragne things started to happen

- I swapped the left and right audio path VCA - BAM - now both channels are passing through audio BUT no compression
-Swapped back, still both sides work, and still no compression (that was no surprise just wanted to make sure what happens with the audio passing through if I switch it back)
- So I swapped the original right side VCA with Sidechain VCA - BAM - both side passing through audio and compression is happening
-Just to make sure I swapped back the VCAs again, so everything is at it's original place now - guess what? YES, audio passing through, compression happening.

Is it possible that maybe the VCA's somehow got loose in their socket and I just had to refit them? Any ideas to fix this so in the future I don't have to open it up from time to time to refit those vcas?

Also still trying to figure out what could cause the extra voltage on the voltage regulators input leg.
Further DC checking is happening right now, trying to figure out which part decided to give up after a few months

 

[Script]

Weak / bad solder joints ?

 

[rikkord]

You're saying this for the VCA or the DC problem? Also I don't think so since this unit is not a freshly built one that is under troubleshooting. This one was finished and ran properly for quite a few months now.

For the VCA's they are a little loose in the socket so that may be the reason after all.

For the DC issue I just measured 44V on the output side of the rectifier between the two output legs which seems fine since the Vf is 1V on this component and the input is 2x16V AC so after all maybe the 22V on the input side of the voltage regulators are fine?

 

[frejo89]

Hi Guys,

I have a very short question concerning this build

I got the GSSL ready 2 days ago and everything works just fine.

Theres just one last thing confusing me. Wenn I dial the Release switch to "AUTO" I can here a slightly distortion. Its not that crazy, but you can here it. Is there a chance to get rid of it?

Its really just this one little thing - everything else is just fine.
Thanks for having a little hint

Thanks

 

[Script]

Orientation of both tantalum caps in Automode circuitry is correct ? u47 & 6u8

 

[frejo89]

ah, wait. Thats a point. switched the tantalum caps to film capacitors.
I avoid tantalums in general because there a still the most risky components in case of exploding.

So I went with to much "safety" here - thats the mistake i think.