GSSL HELP THREAD!!!

[cray]

Hello guys.
Just some questions about  some troubles building a #12rev.  I need help.

By mistake a 78L12 was incorrect  , so has been replaced  .
Checking voltages on 15v & -15V  the multimeter reads: more than 30 V In AC  .. nothing in CC!


also replaced 7812 & 7915 , Can´t replace the 7815 ( i´ve got any  here) may be it is the problem and is damaged. don't know until i replace it.
the toroidal gives the correct values-


tomorrow will replace  7815 and 1000uf / 63v capacitors also , 

any suggestion ?

Thanks in advance!

 

[Gustav]

tomorrow will replace  7815 and 1000uf / 63v capacitors also , 

any suggestion ?

1. Check values when they have been replaced (why are you replacing the caps?).

2. Post measured values rather than "more than 30V",  and specify where you measured.  For example, if youre measuring 32VAC across the serial-connected trafo, its perfectly normal.

3. Start by checking DC values relative to ground. You can google the data sheet for the regulators and/or ICs and see which pins are V+ and V- (For example, even an image search for LM7815 will show you which is the input pin (unregulated voltage), and which is the output pin (regulated voltage)).

Gustav

 

[cray]

Thanks Gustav.

fixed the problem!!
I was measuring in the wrong way.  now i get  the correct voltage on +15 & -15V measuring  from trafo ( center)  and 15v rails.

as 78l12 was placed in the wrong way.  has been replaced , & one resistor burned ( 10ohm )  also replaced.


was thinking to replace some caps if they are fault  , but no ..they are working  good.

yes. i read the data sheets to measure voltages on ics..and seems to be ok.
the unit is working perfect.

Thanks for your help!

 

[cray]

Good morning guys.

Just a simple question.
would like to add a lorlin  rotatory pot  to my gssl , instead a SPST  with only one selectable  frequency on hpf side chain filter. ,

to do that , i suppose i need a one pole lorlin pot  , right?
the first position would be  off.  the next positions  would be different freqs. 
please could you pass to me a list of freqs with the needed caps for each one?

i have been searching but a lot of posts here.


thanks in advance!!

 

[Gustav]

please could you pass to me a list of freqs with the needed caps for each one?

You can calculate the list and needed caps yourself, if you take a look in the assembly guide on my site (page 15). Saves us from trying to guess which list of frequencies you would like too 

Remember, caps dont come in every imaginable value, but you can connect them in series and/or parallel for odd values if you are picky.

Gustav

 

[cray]

Thanks Gustav.

please could you pass to me a list of freqs with the needed caps for each one?

You can calculate the list and needed caps yourself, if you take a look in the assembly guide on my site (page 15). Saves us from trying to guess which list of frequencies you would like too 

Remember, caps dont come in every imaginable value, but you can connect them in series and/or parallel for odd values if you are picky.

Gustav

 

[joelb]

Hi guys and girls.

Apologies, I have looked extensively through the posts but haven't found anything that helps...

I have finished my first build - a lovely GSSL compressor. However, I have some problems: -

- The compressor only compresses when the Bypass button is pressed in and light is on (which should mean it's bypassing not activating)
- The ratio knob works the opposite way that it should - 10 is working as 2.
- Compression is only working on a ratio of 10 - 4 and 2 both make the needle slam to the 20dB but no compression.
- Now, since attempting to 'fix' problems, I have damaged the track on the PCB where the live power enters the board (brown wire). I have attempted to fix that by scratching off the surface around that track and soldering the wire back on to the copper surface but now I have a very loud ground hum.

Sorry guys, I know I sound such a noob!

I have attached pictures of the main board (it's one attachment max per post?) but can attach other pics - 2nd board, wiring etc. Everything has obviously been done according to the manual - I really took my time not to make any errors, but still there are errors unfortunately.

I would really appreciate any help you guys with more experience can offer, thanks very much indeed.

Have a great day

Joel

 

[Patch]

Happy Friday guys! Well....not so much for me otherwise I wouldn't be here ahah.

I built my GSSL back in 2008, worked great. I have one turbo board and super sidechain, all working good. Then I changed the VCA to DBX202 Black cans but never got them working perfectly, but useable, So recently I went back to the 2180LC but having gone back I have a problem. The Right channel is about 6dB lower than the Left. I understand this seems due to a + or - on the XLR pins not making connection......but....it doesn't seem to be this...

-Checked voltages everything seems fine, also on all opamp pins.

-Swapped all opamps from left to right / the problem does not swap channels.

-I have bypassed the Left and Right VCAs by jumpering pins 1 to 8 (also stripped all resistors and caps from the 202 emulation circuit) so problem doesn;t seem to be the SC

- Even in bypass the level difference is still there by almost 6dB

-Have replaced all 100uF caps in the output section and all the ceramics and almost all 100nf caps in the output section

-Checked and double checked and traced IN&Out molex connections

-bypassed the board and plugged xlr molex to board connections into each other, the stereo level is perfect so clearly issue is on the board/circuit.

- checked the 15k/27k (have used both) unity gain / VCA input resistors, they are perfect. CHecked the VCA output 15K resistors too, they are also fine.

-I re-tinned all soldering in the input and output section, didn't help.

-I haven't checked/replaced the input section caps yet.

-I haven't replaced the majority of caps in the IN/OUT section yet but it used to work fine and everything I replace on the board doesn't help. My soldering tends to be pretty good so I'm tearing my hair out a bit here.


Does anyone have any suggestions? Any help would be mucho appreciated.

 

[Patch]

Oh I forgot to add that the level mismatch is only from around 40/50- Hz up to 20KHz. If I go lower than 40/50Hz with a noise generator (sine) the audio goes equal across the Left and Right stereo image. Could that be a clue? 

 

[Patch]

Wow group diy is back!!! thank the lord.

Just FYI I resolved the problem. Don;t know what it was but i recapped and 're-resistored' the entire input and output section. It fixed the level, I'm within 0.1 dB  difference generally now. What a royal pain in the ass that was... 

 

[Potato Cakes]

At long, long last, I finally got this guy to start compressing. All I had to do was build a stereo 1176 (I'll post pics later),  build a 4 channel EZ1290, build another GSSL, a slew of 500 series preamps, a bunch of Bo Hansen DI's and then go on tour and then come home. That's when I saw that I had the blue and green wires backwards on the ratio PCB. Hilarious. I even got it working properly with the Side Chain board. Now I have to wait for some construction to finish on the house and then I can put the studio back together and actually use it. For the time being my confidence is back till I build something else that doesn't work.

Thanks to Gustav and Jakob for a great project.

Now I just need to find where I put all the screws and bolts to put it back together.


Thanks,

Paul

 

[Gertius]

Hi guys,
while I didn´t read all 300 pages I have used the search function and couldn´t find anything, so apologies if this has been asked before.

I have recently acquired a used GSSL (PCB Rev #11)  with the Turbo mod installed and I´m in the process of checking it up.
The thing is, on the bottom of the Turbo PCB there are additional components/bridges (see pic attached) which I couldn´t find in the official docs.
Does anyone know what these are for and could please point me to the respective info?

 

[Gertius]

Also, there seems to be be something wrong with the GR meter.
I´ve tried the screw, but I can´t get the needle to point at 0dB, when there is nothing happening.
I remember reading somewhere that the meter does not need any other calibration?
Is there a component I could change or check to make the GR meter point to 0dB, when there is nothing going on?

Thanks so much already!

 

[Bowie]

Hi guys and girls.

Apologies, I have looked extensively through the posts but haven't found anything that helps...

I have finished my first build - a lovely GSSL compressor. However, I have some problems: -

- The compressor only compresses when the Bypass button is pressed in and light is on (which should mean it's bypassing not activating)
- The ratio knob works the opposite way that it should - 10 is working as 2.
- Compression is only working on a ratio of 10 - 4 and 2 both make the needle slam to the 20dB but no compression.
- Now, since attempting to 'fix' problems, I have damaged the track on the PCB where the live power enters the board (brown wire). I have attempted to fix that by scratching off the surface around that track and soldering the wire back on to the copper surface but now I have a very loud ground hum.

Sorry guys, I know I sound such a noob!

I have attached pictures of the main board (it's one attachment max per post?) but can attach other pics - 2nd board, wiring etc. Everything has obviously been done according to the manual - I really took my time not to make any errors, but still there are errors unfortunately.

I would really appreciate any help you guys with more experience can offer, thanks very much indeed.

Have a great day

Joel

The first couple sound like you just have your wires crossed up.  Should be an easy fix on those and it might end up correcting some of the other things.
The trace issue sounds like you may have scratched into a wrong or neighboring trace.  Can you go in underneath the board and solder to the original hole?  There's a couple other things you can do but w/o a GSSL board I'm hesitant to say anything specific as I don't know if it will work on your board.

(Edited to avoid confusion based on info below.)

 

[gyraf]

GSSL uses a linear meter, indicating 0dB Gain reduction at zero meter current (resting to the left) and 20dB at 1mA.

It will NOT work "backwards" with a VU-style meter like the 1176 etc.

Jakob E.

 

[Gertius]

GSSL uses a linear meter, indicating 0dB Gain reduction at zero meter current (resting to the left) and 20dB at 1mA.

It will NOT work "backwards" with a VU-style meter like the 1176 etc.

Jakob E.

Thank you very much for your reply. It turned out that removing the plastic cover from the meter allowed for a larger adjustment of the 0 point, than only using the screw on the front cover. I´ve adjusted it and then had to remove the plastic pin  from the screw on the inside, so it wouldn´t touch the meter needle anymore. works fine now.

Also I´ve figured out what the additional components were on the Turbo board, it was for additional Ratios 1.5:1 and 8:1.

The build had quite some problems though, which I was able to fix during the past two days.
In Turbo mode it first did not react at all to the left input, it only compressed if there was input on the right.
I´ve first removed all the mods from the Turbo board. Then it reacted to both sides, but in different strengths.  I´m not quite sure if that´s what finally got it to work, but I noticed that in the Turbo board there was an additional resistor 47 Ohms between pin 4 of the VCA and ground even though it used the THAT 2181B VCA.  After removing the 47 Ohm resistor, it worked fine.
Now I´m searching for a final test procedure, to see if everyithing is really working as it should. I´ll start with the META...

Thanks again!
Cheers

 

[G-Sun]

Hello folks!

I've put together my gssl. Gustavs kit, with case from frontpanels.de
Have some problems. Unit not working

AC
Green-red: 18,2V
Green-yellow: 18,1V

DC
11,9V (on optional 12V)

Power-light working

Not seen any action on vu-meter.

Have had working left-channel, once (seemed good, GR working, makup, attack, release, sidechain, on/bypass).
Now it seems dead.

Bypass worked first time, now it's not passing audio in bypass

Images:
https://www.dropbox.com/sh/c83xn0o3w742gxu/AACs1HC4JKPda5_10OmIqBp5a?dl=0

 

[G-Sun]

Checking my connection i/o. Seems fine.
Next is ic voltages.

 

[Gustav]

Not seen any action on vu-meter.

Install the missing 2K resistor to see action on the DC meter.

Checking my connection i/o. Seems fine.
Next is ic voltages.

Would be a good idea for a next step, yes.

Gustav

 

[G-Sun]

Thanks!

There's something odd with my +15 voltage.
It reads -0,88V
My neg -15V seems fine.