GSSL HELP THREAD!!!

[dirtyhanfri]

Great, Thanks!

 

[Henkkamachine]

Hello!

Came up with gssl with 2180 VCA's. I did all the mods needed referring to Matt Fischer's page. Voltage measures i tested referring to PDF-file which is hanging in this thread and everything seems to be OK (w/o vca). GREAT 

But. I've heard that this compressor should also make some compression: i threw VCA's in and now i got this:

* Passes audio, no distortion
* THRESHOLD doesn't do any changes to sound. No meter changes. No compression. TL072 gets changes to PIN2.
* TL072 pin 1 stays in +7.8V no matter what (Resistances on the legs are changed by thres knob)
* Bypass switch seems to be working (http://www.groupdiy.com/index.php?action=dlattach;topic=47.0;attach=11864;image
* Make up gain works as well
* Ratio knob changes voltages (0,22V, 0,34V, 0,38V) so it's okay?!
* When using bypass i can hear and see from pro tools that the attack and release are working.
* Turning makeup gain clockwise-> meter needle goes left.

Need more info?

Triple checked most things and changed 074 and 072's. No change.

Any thoughts on it? What i should be looking for? I didn't notice in this thread any project with exactly same symptoms  :-\

Thank you to all guys in this thread. Learned so much!

/Henrik

 

[Henkkamachine]

Hah! Found the issue! NEVER underrestimate the power of good magnifying glass! Tiniest bit of solder in "tight" place. Now it does what it should do! Had to wake up my wife for listening and watching the meter bounce on some drums!

I'll also upload a photo of the problem if someone is having same kind of situation!

Now i'm gonna do the enclosure ready for some photos and build a turbo mod!

First "advanced" electric DIY project after passive summing mixer and DI..  Many Thanks to you all, especially Jakob E.!

/Henrik

 

[Mattnezz]

Any discussion on this autorelease resistor mixup?
If you compare the original time constants schematic to the Gyraf version, those 91k and 750k in the auto-release setting seem swapped... To me it seems the original is a bit faster in the beginning...

 

[Harpo]

Any discussion on this autorelease resistor mixup?
If you compare the original time constants schematic to the Gyraf version, those 91k and 750k in the auto-release setting seem swapped... To me it seems the original is a bit faster in the beginning...

Mixup is only in schematic (and there are some other spots that don't match the pcb).

 

[ptron]

Any discussion on this autorelease resistor mixup?
If you compare the original time constants schematic to the Gyraf version, those 91k and 750k in the auto-release setting seem swapped... To me it seems the original is a bit faster in the beginning...

meaning should be 91k /6u8 RC loop before 750k/u47 loop and then ground?

Sorry i just saw the drawing

 

[Mattnezz]

Mixup is only in schematic (and there are some other spots that don't match the pcb)

Thanks for pointing that out, the Gyraf PCB seems allright!
My first clone was fitted inside a Hammond E-size enclosure, so I had to redesign the controlboard to fit. Release felt weird though... I'll swap the resistors.

 

[dirtyhanfri]

I'm finishing my GSSL, it's my third project, and I'm so happy about it, looks much nicer than my previous buildings (La-4 & SSL 9K) Still gotta work on the rear pannel... Voltages are OK, and it passes audio, but doesn't look to work properly. I expect to make it work today.

Some porn....

 

[ptron]

hey looks great!! i was thinking before i saw the front pannel attatched that the molex at the ctrl pcb would be a tight squeeze!!

great build! would love to see finished unit

 

[dirtyhanfri]

the molex at the ctrl pcb would be a tight squeeze!!

Actually it is, but with some carefull wire bending everything was ok

It sounds, and compress, but the threshold pot doesn't seem to work, also some attack and release positions gave me no compression. I checked the control pcb visually and found some weak solder points, gotta work on that tomorrow, anyway, any tips about it? (I will look around for related issues)

Thanks Gyraf for this great project!

 

[ptron]

is the threshold acting like it was very low? might need the 47k resistor on the leg maybe?

hope it gets well soon!

 

[dirtyhanfri]

is the threshold acting like it was very low? might need the 47k resistor on the leg maybe?

hope it gets well soon!

It has the resistor already, under the red shrink tube. Actually, i found a bad resistor joint in the 3M9 resistor next to the ratio switch, in the point between "I" of the 10 pin connector and one of the threshold pot legs, I think the problem will come from this, also I will check resistor values in the controlboard.

I'm gonna change the 7815 & 7915 (Actually, farnell gave me a wrong transistor for the 7815, and I bought some spares in my local store) because sometimes it have some strange issues when I turn on the unit, meter going crazy, led don't working and so, I've read in this thread it could be about the regs...

Thanks for the advices!

 

[Arnoid]

This weekend I fired up & tested my gssl  for the first time everything worked directly and the unit sounds very nice
I first builded a standard GSSL without modPCBs (SSC, turbo & CrC) so I certainly know I have a working one before I start with the mods ..

I have al little problem with the volume that drops like 6db or something if I plug the compressor in one of the inserts from my groupbus or masterbus..

I use TRS connecters instead of XLR and connected them like here
O + Left. Pin 2 on left XLR. Goes to left TRS jack tip.
O - Left. Pin 3 on left XLR. Goes to left TRS jack ring.
O Ground. Pin 1 on both XLRs. Goes to both TRS jack sleeves.
O - Right. Pin 3 on right XLR. Goes to right TRS jack ring.
O + Right. Pin 2 on right XLR. Goes to right TRS jack tip.

Output is also on 5 pins but + and - swapped, and also right and left swapped:

O - Right. Pin 3 on right XLR. Goes to right TRS jack ring.
O + Right. Pin 2 on right XLR. Goes to right TRS jack tip.
O Ground. Pin 1 on both XLRs (should go from XLR to star ground, not to here)
O + Left. Pin 2 on left XLR. Goes to left TRS jack tip.
O - Left. Pin 3 on left XLR. Goes to left TRS jack ring.

source: http://www.groupdiy.com/index.php?to...1614#msg571614

I think it has something to do because you need to use balanced cables with the GSSL? Now I use normal insert cables 2x mono to 1 stereo (2xTS to 1xTRS) not balanced ..

 

[dirtyhanfri]

Working!!

Like many times in this thread.... it was a bad solder, also I've a issue around the release, when switch is in position 3 the unit doesn't seem to compress, , also, in position 6 I get distorsion in the sound...

Also, the threshold pot acts backwards, I suppose just swapping wires going to pins 1-3 of the pot...

I like the compressor, looks like lots of fun for me now...

 

[dirtyhanfri]

Like many times in this thread.... it was a bad solder, also I've a issue around the release, when switch is in position 3 the unit doesn't seem to compress, , also, in position 6 I get distorsion in the sound...

Ooops!, just checking gyraf docs for the gssl I realised Release switch is just 5 pos.

 

[dennisp]

Hi guys,

I need a little help.

I have assembled 2 Gssl Gustav rev #7 boards and I'm measuring the voltages without anything attached to the main board.
All voltages except -12V are fine. The -12V measures -23.6V and I have no idea what could be wrong.
It's the same on both boards so I'm thinking that I must have mounted something in reverse.

Does anyone have an idea as to what could be wrong?

Update - I've spent a couple of hours scraping off potential short-outs with no luck.
Then I made a new observation:
When measuring ohms between 0 and +12 (which is working) I measure about 10K ohm.
When measuring ohms between 0 and -12 (which measures -23,6V) I measure a rising and falling value between about 9K ohms to over 2000K ohms (it does fall again if I'm patient enough).

Mind that no IC's or VCA's are connected yet...

Is this normal or hopefully a pointer towards the culprit?

Positive regards
Dennis

 

[monobass]

Hi, can anyone tell me knobs these are on this white GSSL?

 

[kante1603]

Hi, can anyone tell me knobs these are on this white GSSL?

Hi,

the brand name is SIFAM.

Cheers,

Udo.

 

[monobass]

Thanks Udo... I'm guessing they are around 20mm diameter?

 

[Mattnezz]

Does anyone have an idea as to what could be wrong?

Maybe you fried, or wrongly connected the 79L12 or 7912 regulator.
Some of those regs require a load to function properly, since there are no opamps to feed, there is no load... So you might wanna try to hook up a, say 2k resistor between a -12V point and GND for measurements.
See if you get a -12V reading now. If yes, swap the resistor with the cheapest opamps (TL072/074) and measure again...
hope this helps...