GSSL HELP THREAD!!!

[weiss]

Sorry typed in phone.

1. Check 15V , -15V, 12V and -12V voltage in IC's, where they should be
2. Check are those voltages in IC's where they should not be.

First I always check PSU voltages. Are those right and is there no DC where it should not be.

Just checked. I only get -15V and +1,2 V on power rails from transformer. ???

here is the one i use: https://www.reichelt.de/printtrafo-10-va-2x-15-v-2x-333-ma-rm-27-5-mm-ei-48-16-8-215-p27490.html?

 

[scott2000]

Maybe  try measuring from the actual transformer pins just to make certain first......??

 

[Olegarich]

So that's it. First you need to find where is yours +15v . Check  what you have before and after voltage regulators.  Also check, if pinout on the transformer is the same on pcb. I mean if secondaries are there where they are marked on pcb.

This transformer is 10VA, 5VA each secondary. If I'm not wrong it's minimum what is needed for this compressor. But if you'll go for the mods or some lighting, it maybe not enough.

First thing I would do, I would swap transformer for the  30VA and the one you can put outside the pcb. I'm using toroidals.

Secondly remove all the ic's before you burned something. Before you put any IC, your Voltages should be right. 

 

[peterzho]

Hi Yall

Just finished the build, no sound at all in bypass or not, i was poking around with a probe and got no signal on the input opamps but some of the resistors next to the input opamps had signal.

Please advice on where I should start probing

Thanks!
Peter

 

[gyraf]

...read this thread for suggestions. you are not the first...

Jakob E.

 

[Olegarich]

If you're loosing signal on the input section, then it's easier. Basically,  you open schematics and start chasing signal from the input on each part.

1. Make sure you  have signal on the input of the pcb and pins are soldered right way.
2. Check are your voltages on op amp and double check for orientation,  so many lads messed up with orientation and make sure you've put NE5534 not NE5532 there.
3. Check if you're getting signal on 2&3 pin on op amp, if you are - then check pin1 of op amp,, if you getting signal there then your input section is working well. By the way, then signal goes to the 27K resistor so it's ok to have signal on one end and see no signal on the other, if you're using scope.

 

[peterzho]

Hi yall

My 79L12 burned out, i remembered smelling something burning when i first turned it on.

Switched a new one in, got sound, but now my second 79L12 is burning out again! I smelled it, touched it it was super hot, it's probably dead again at this point

any tips?!

Edit: turned it on again, 79L12 still giving -12, the 22R resistance looks a little toasty, it's reading 13Ohms now. the dc resistance to ground from the out of the 79L12 reads ~4K

tips again?

 

[Olegarich]

Hi Peterzho,

Something is sucking your current.
Probably there is a solder joint somewhere. 

12V is used in VCA section, for the threshold, make up and ratio. Check for solder joints in 12V traces and near.

If you made a turbo mod check there.

Check orientation of those 78L12 and 79L12

Check 197 page, somebody had similar problem but I may be wrong.

 

[weiss]

So that's it. First you need to find where is yours +15v . Check  what you have before and after voltage regulators.  Also check, if pinout on the transformer is the same on pcb. I mean if secondaries are there where they are marked on pcb.

This transformer is 10VA, 5VA each secondary. If I'm not wrong it's minimum what is needed for this compressor. But if you'll go for the mods or some lighting, it maybe not enough.

First thing I would do, I would swap transformer for the  30VA and the one you can put outside the pcb. I'm using toroidals.

Secondly remove all the ic's before you burned something. Before you put any IC, your Voltages should be right.

Maybe  try measuring from the actual transformer pins just to make certain first......??

thanks guys, i fixed some lifted traces on the back of the pcb and now i get better values. with everything running (compressor on, ligths etc.)  i get now around +9V and -15V. Is that enough to run the compressor or do i need a completely different toroidal transformer for that? I thought it would be enough..  :-\

 

[scott2000]

That doesn't sound right..... Not sure why the rails are different ....I'd figure that out.........

but, maybe you need more power....like Olegarich mentioned...

.. The schem says 15va transformer???

 

[weiss]

That doesn't sound right..... Not sure why the rails are different ....I'd figure that out.........

but, maybe you need more power....like Olegarich mentioned...

.. The schem says 15va transformer???

hey scott, you're right, anyway now i checked again, it says 14,92V on both rails. maybe i didn't measure correctly..  ?!

where could i possibly "jump in" and get voltage for my bypass LED which gets switched by the 3PDT on the front panel? This rev doesn't have additional 12V rails for lights and relays... ?

now the audio is passing without any hum that's great!
attack, release, ratio and make-up also work.

BUT: the threshold doesn't seem to work and apparently my GR meter (http://shop.frontpanels.de/product_info.php?info=p39_classic-db-meter.html) doesn't really move (just around 1mm back and forth to the music, even in bybass). do i need to take a closer look again to the bypass schematic? i did exactly what Olegarich showed me in his wiring scheme..
And when i increase make-up the GR increases.. ???

 

[Olegarich]

For the led, probably it would be better to take from 15v rail with drop resistor. Those voltage regulators can handle more current then 12v regulators.

Due to threshold problem - first check what voltages you get on threshold pot? Check for dc. In one end it’s 12vdc, in middle should change when you rotating it.

 

[weiss]

For the led, probably it would be better to take from 15v rail with drop resistor. Those voltage regulators can handle more current then 12v regulators.

Due to threshold problem - first check what voltages you get on threshold pot? Check for dc. In one end it’s 12vdc, in middle should change when you rotating it.

thank you Olegarich,

i can read top: 12V, bottom -12V and the wiper changes according to pot position. so i guess, that's correct??

 

[Olegarich]

-21V ???? You meant -12V?

 

[weiss]

-21V ???? You meant -12V?

yes sorry, corrected it

 

[mingus77]

Problem: DISTORTED sound. Sorry if this is mentioned before, but I've read through a lot of posts now.. 4 days with new IC`s and fixing things that could be wrong. But still the same, a lot of distortion/saturation (overkill). Everything works, except from the sound. Zero noise, and all knobs working. Bypass too. It´s the same distortion when bypass is in. When I lower the input volume I can get a clean sound. When sending a more normal leveled sound in I get distortion. Seems like the GSSL gets a to hot signal in. But I don't know what components that adjusts the "volume" in the GSSL.
Using THAT2180´s
Any clue is appreciated! Pretty frustrated here, feels so close to a solution, but now I'm lost.
Left/right is just the same. Everything sounds good though it sounds like a nice stereo distortion box

I have only added the main board and the CRC so far. The rest comes when this works the right way.

You'll be the godfather of my next child if I get this done! (Oh wait, I have to many already)

Mingus

 

[scott2000]

Do you have some voltages you can post???? What are your supplies looking like???

 

[mingus77]

Oh I wish I could just bend them straight again
I can see I might have to many resistors connected. If this «map» is right .
I will do some measuring, but first I have to do some research on how and what to measure
Thanks so far!

 

[scott2000]

lol...I actually edited that part///

You should be able to peek at some voltage at those jumpers marked + 15 and - 15 to get a quick ok there........?? Just reference to ground and each one......


Yeah I noticed you had some extra stuff compared to weiss but haven't looked further yet...

 

[mingus77]

Ok that part was easy Not in front of it now, but it was close to 15v. 14.89v or something  near.