GSSL HELP THREAD!!!

[vdrumer18]

Hi guys.
I'm desperate for help here. I'm done bulilding my Gssl with the turbo board, but after i checked my main voltages and put in my ICs the compressor ITS NOT PASSING AUDIO. no matter what i do!. the only weird things that i noticed are these: if i connect power supply pin header to the turbo board like shown in the instructions, i get -12V at pin 4 and +12V at pin 11 of the TL074 chip on the Turbo board (supposed to be the other way around). AND  when i turn the ratio switch to the 10:1 position the meter slams fully to the right. it does not do this when i take the turbo board out of the unit. PLEASE help........

you guys rock!

 

[3nity]

I'm ready to finish my GSSL build and was wondering if this Led meter will work on the GSSL??

 

[angelo2979]

hi there ,

I move to this official gssl help thread to try to find a solution for my first gssl...

----------------------symptoms:
This is the problem:
the controls don't work, nothing happen if I turn the ratio/treshold/attack/release/make up switches, the meter doesn't move, and the bypass switch doesn't affect the sound...

But...
there's audio going out the gssl, a low signal (the left channel is a bit higer than the right one) and it seems that my rails are ok: +15,00/-14,8 /+-11,9

-----
I'd like to locate the problem so I can better check for it, also because I'm not the best in electronics...

for this project I've used THat2180 for the Vca section; all the leds work properly, and so the cables to the control board are properly wired; on the control board I have 12,v (11,9) and the opamps receive voltages, but i've found some potential problems:

My two ne5532 (in the output section) have different voltages:

the left channel's opamp has:

pin 1, 2 & 3 = 0v
pin 4          = -14,8v
pin 5,6 & 7  = 0v
pin 8          = 15v

my right channel's ne5532 is the same but it has -8,6v on pin 1 and +8,62v on pin 7, could this be the reason why I get different signal levels from my left and right channels (right channel is lower than left)? how could I fix it? 

all My NE5534 (on input and VCA sections ) have:

pin 1    = 12,6v
pin 2 & 3=0v
pin4      =-14,8v
pin5      =-0,5v
pin6      =0v
pin7      = 15v
pin8      =12,6v 

if anyone knows where the problem could be, I'd really appreciate his help...

Thank you everybody!

 

[trancedental]

Angelo2979 you should 100% check the wiring to the control PCB, make sure there are no shorts or solder traces where they shouldn't be, also check around the NE5532's for shorts & use a magnifing glass to rule out any problems. Also does your GSSL pass audio without the Control PCB connected, it should work as if in bypass mode

These are the approximate voltages & readings your should be gettting



TL074


Check if you have signal coming at the input of your sidechain: pin 7 of the TL074.
You must have DC varying with signal at the output of the sidechain: pin 8 of the TL074.
You should have something like 2V at TL074pin8 (meter drive) when gain-reducing 20dB
Pin14 should change with the ratio settings (and with the signal level)


TL072


Pin1 should change with threshold variations (and with the signal level)
Pin7 should change with makeup variations (and with the signal level)

Control PCB

C BypassAttackREL TL074 9/10 > 8
B Ratio > 1N4148 TL074 13 > 14
A Ratio TL074 13 > 14
0
-
D Post Attack C
G Meter
E Makeup Bypass TL072 6/5 > 7
F Threshold> TL072 2/3 > 1
+

TL074

OUT> 7
OUT> 1
OUT> 14
BYPASS.....

IN> 9-/10+
OUT> 8


TL072

IN> 6-/5+
OUT> 7
> VCA'S

Working GSSL

1) TL074CN
*****************
1/+0,24
2/0,00
3/0,00
4/+12,07
5/0,00
6/0,00
7/0,00
8/0,02
9/0,02
10/
11/-12,32
12/0,00
13/0,00
14/0,36

2) TL072CN
*****************
1/7,83
2/0,00
3/0,00
4/-12,29
5/0,00
6/0,00
7/0,00
8/+12,05


3) NE5534AP
*****************
1/+12,37
2/0,00
3/0,00
4/-15,14
5/-0,60
6/0,00
7/+15,07
8/+12,38


4) NE5534AP
*****************
1/+12,41
2/0,00
3/0,00
4/-15,17
5/-0,60
6/0,00
7/+15,07
8/+12,42


5) NE5534AP
*****************
1/+12,43
2/0,00
3/0,00
4/-15,14
5/-0,61
6/0,00
7/+15,07
8/+12,43


6) NE5534AP
*****************
1/+12,36
2/0,00
3/0,00
4/-15,15
5/-0,61
6/0,00
7/+15,06
8/+12,37


7) NE5532P
*****************
1/0,00
2/0,00
3/0,00
4/-15,15
5/0,00
6/0,00
7/0,00
8/+15,07

NE5532P
*****************
1/0,00
2/0,00
3/0,00
4/-15,15
5/0,00
6/0,00
7/0,00
8/+15,07

9) THAT 2180LB
*****************
1/0,00
2/0,00
3/0,00
4/0,00
5/-10,89
6/0,00
7/+15,07
8/0,00


10) THAT 2180LB
*****************
1/0,00
2/0,00
3/0,00
4/0,00
5/-10,86
6/0,00
7/+15,07
8/0,00

11) THAT 2180LB
*****************
1/0,00
2/0,00
3/+5,5
4/0,00
5/-8,66
6/0,00
7/+12,06
8/0,00

 

[angelo2979]

thank you for the scheme, very useful!  ;D

I checked all the voltages and I noticed that the tl072 was not connected well, so I fixed it and now the make-up knob started to work but there was still the problem of the right channel, lower than the left channel. So while I was checking with my tester the voltages of the that2180, I don't know what happened but I heard some "pops" and now the right channel is the same as the left (maybe it was just a bad contact). Also there's no more voltage difference between the two ne5532 in the output stage.

But... all the other controls don't work at all, and so the meter. now, the bypass switch just reduce the original signal I send to the compressor (the same reduction I get turning the make up knob to the minimum)...

--here the results of my voltage-check:

TLO74:

--pin 1 hasn't got a stable voltage...it's about 0,17v (instead of the 0,24 of your working ssl)
--pin 4= 11,9v
--at pin 7 I get 0v; it does not change with treshold variations.
--at pin 8 I just have 0v, it does not vary with signal; I have 0v also at pin 9,10,12,13
--pin 11= -11,71v
--pin 14 looks ok, it changes with the ratio settings
 
TL072:

--pin 1 changes with treshold variations; I have -0,08v (with treshold at minimum) and  2,98v (with treshold at maximum), instead of the 7,83v of your gssl
--pin 2,3,5,6,7 have 0v
--pin 4= -11,7v
--pin 8= +11,8v

all my ne5532 and ne5534 have almost the same voltages as those of your working ssl (small variations).
the same is with the two that2180AL of the VCA section: the only difference is that they have -2,88v at PIN 5, insted of -10,89
the sidechain that2180al has 0,23v at Pin 3 (instead of 5,5v) and -2,91v at Pin 5 (instead of -8,66)

how can I fix these problems? which could their cause be?

thanks for your support.

 

[trancedental]

Confirm if you have input signal (AC) on the pin 7 input TL074, if there is no input signal trace the circuit back by looking at the schematic & opamp specifiactions & see where in the circuit the input signal ends, that's where the problem will be so look for faults around that area.

 

[angelo2979]

should I check for AC or DC? AC gives me something like 0,2  not a stable signal... DC gives me 0v

Do I need and oscilloscope or something like that to trace the whole circuit? I only have got a cheap tester...  ;D

and I'm not so good to read the schematic... where should I check for faults?

 

[angelo2979]

just to report...

I also tried to remove the TL074 and looked for DC at Pin 7...It gave me a voltage changing with the audio signal and with treshold variations, from 0,55v to 0,77v... could the TL074 be broken? 

 

[angelo2979]

i tried to change my tl074 but it's all the same...any help? what should I check?

 

[trancedental]

Send a constant audio signal like a test tone or similar to your GSSL & check if you have control voltage coming out from pin 7 of the TL074 & then TL072, the control voltage should be arriving at the 1K resistors near the VCA's.

You should be able to trace the control voltage around the circuit so study the schematic to follow the signal flow.

 

[Vito Janeiro]

External Sidechain weirdess.

Hello everyone.

I have the basic GSSL clone with super sidechain board mounted and everything works flawlessly exept the thing that I noticed with external sidechain activated.

The signal from sidechain input triggers the compressor fine, but also the original signal from L+R input is summed to sidechain for some reason, but on lower level!!! This is not how it´s supposed to work, please help me, the external sidechain is really important.

Yeah yeah wiring checked etc the normail things...

Wbr,

Vito Janeiro

 

[Adky]

Rev#7 PCB, use dbx2150 chips, and 1MA DC Meter , got the threshole at Max and Ration 1:10 , attack Fast , Release at Auto , the Meter only show about .2 - .22 but I can hear the sound pressure level goes down and some compression, not sure is it really compressing in it's full ability ,is this normal? or something not right?
Please help!

 

[audiophreak]

Hi,
    Noob question, sorry 

  Putting together a parts order for 2x Gssl, are the resistors 1/4w ?  I see the power trans secondaries are 2.5va, don't want to order wrong value.
  Is there a parts list for the Super Side Chain?

    Thanks

 

[digichild]

sometime ago i bought some dbx ci 1252h2 in the blackmarket as substitute for that 2180 or similar
not sure if i still want to use them...maybe for the sidechain?

 

[3nity]

I have a question here...

I want to make my Gssl with sidechain high pass (Greg layout) switchable to turbo mod.

Now how could this be done? since i see the Turbo goes into the 2x 47K resistors and the Sidechain replaces thoses resistors??

Thanks.

 

[crisotop]

You need a second highpass-filter board for the turbo mode, since your sidechain is now stereo instead of mono as in the original "Gyraf" mode.

hth, christoph

 

[3nity]

Remember i want to make the turbo mod switchable?
So if the turbo is off...then i have a normal gssl working with 1 sidechain high pass...
If Turbo mod is ON....Sidechain is bypassed

now how to do it?

Seems complicated but i only have 1 high pass filter...
if it doesnt work i'll breadboard the other SC.

Thanks?

 

[digichild]

sometime ago i bought some dbx ci 1252h2 in the blackmarket as substitute for that 2180 or similar
not sure if i still want to use them...maybe for the sidechain?

nobody knows?

 

[crisotop]

Remember i want to make the turbo mod switchable?
So if the turbo is off...then i have a normal gssl working with 1 sidechain high pass...

The easiest and most flexible way to do it would be using two sidechain boards. If you want to make it switchable with no sc-filter in turbo mode you need a 2pole 2deck switch - all you need to do is have a look at the two 47k summing resistors, if I recall the schematics right, this is the point where you plug the sc and turbo board in audio-wise. So either you have one 47k leg connected, and the second one lifted + turbo board, or you lift both of them and send the signal to your sc filter - this could easily be made switchable. Hope this makes sense, otherwise I would have to come up with a wiring diagramm..

hth, christoph

 

[3nity]

Thanks Chris...
I believe i'll keep the sidechain for another Gssl build
I'll go with turbo switchable and thats all...
Too bad my Front layout looks nice and bussy....

Thanks!

Jorge Aristondo.