GSSL HELP THREAD!!!

[sarakisof]

Hello  folks. I am about to built my first Gssl comp .  I have some other PCBs made in Eagle waiting for others to be added so to make a combined order from China manufacturers (those with 2-5 bucks/10pcs.). But as many of you know, their offer is for  dimensions 100x100mm  and lower.
I m planning to re create gssl in Eagle from schem and  dividing the Main (for example) to  2 or 3 boards, so to decrease dimensions to fit 100x100.
I was thinking one board for Power, a second one for Audio part and a third one the Control but smaller than now (maybe just wire rotary sw. and not mount them  etc.). 
Dont know, just making thoughts, (i ve already made the Power board though ) ,  do you think guys i will have any gnd issues or smthng "bad" by doing this?  Is it risky?

 

[mingus77]

Ok , i guess things Are quiet Ok with my comp now. Though I’m wondering: Is it common got a «pop» between the steps on the release? Using Lorlin switches.
I understand after reading a LOT of posts now that low end distortion is common on hard compression.
And yes, one more.  But that should be on the ad-on page

 

[gyraf]

Yes, pops between steps in release.

Jakob E.

 

[mingus77]

Thanks! Good to know it acts like it should!

 

[sarakisof]

Just a question.  How many 100nF caps are placed on the +15V road(purple) and how  many on the -15V(blue) one? (i mean for in out and vca paths).
Because in PCB it seems like 2 for +15V and 4 for the -4V, but according to schem it's 4 for +15V and 2 for -15V.
I ve attached an image showing that. and also what is this 100nF cap that i have in red circle? It seems like its one leg isnt connected to smthg (the other goes to gnd).
I know that there are some errors in the schem (polarity l/r ins, pins of ic's and 100R position in the outs) and that the PCB layout is correct and works 100%, but i d appreciate if someone here could help.
Thanks.

 

[sarakisof]

Anyone??  :-\

 

[peterzho]

Hi Yall

My sidechain THAT2180 pin 5 is reading around 8V, pretty sure that's the negative supply for that opamp, which should be -12, the 5k1 (on the schematic it asked for 3k9 but probably no biggies) resistor supplying -12 to pin 5 is reading -12 on the side of supply

my  dbx202 emulation that2180s are reading -2 on their pin 5s, while the -15v supply voltage reads fine.

also checked -12 on the ratio , threshold, and TL072, they are all reading -12.

I previously missed a jumper as well as burnt out a 79L12, do you guys think my THAT2180s are fried?

 

[peterzho]

Just checked documentation, seems like my dbx202 emulation ones are working cos their v- is reading around -2.8.

I swapped one of the ones that i thought was working with the i thought fried one, and the working one was reading -2.8 in the sidechain position, while the broken one originally sitting in sidechain was reading 10V+ on the v- pin in the dbx202 emulation position.

gonna order some replacements, wish me luck

 

[weiss]

hey folks,

i managed to get a step closer regarding troubleshooting my gssl. it is now compressing, at least kind of...

i made some samples to explain the problem. i get distortion already at a very low level. the weird thing is, when i enable the compressor mode the needle of the meter goes way left compared to when in bypass mode. i already thought i found the problem, i completely wired the bypass like in the pcb grinder manual but still there seems to be some trouble here.



I also included sc hpf with a cap but the sound even gets more distorted when enabled (maybe normal because of the bass frequencies getting through?)

would be happy about some help. what's the main cause for distortion even at low levels?

i attached the samples below my post (Rename .txt to .zip !!)

thanks
Ansgar

 

[gyraf]

There is a wire link on the control pcb, just above the cable connection - are you sure you have that in place?

(this has been the case in quite a few times earlier in this thread, seeing similar symptoms)

Jakob E.

 

[weiss]

There is a wire link on the control pcb, just above the cable connection - are you sure you have that in place?

(this has been the case in quite a few times earlier in this thread, seeing similar symptoms)

Jakob E.

this one??? i thought that only changes the makeup gain when bypassed?

 

[gyraf]

No, the one just beside where the meter connects.. (can't find image right now)

 

[weiss]

No, the one just beside where the meter connects.. (can't find image right now)

i put a jumper there!

I bypassed the bypass switch by jumping on-off and a1-a2 and i get NO distortion but also no compression.

EDIT: i put the bypass switch back in circuit. Same as before, bypass no distortion, when comp in sound gets compressed and distorted and the GR moves to the right as i turn the makeup gain... ???

any clue?!


Maybe pictures help..

 

[peterzho]

Hi yall

So I'm still burning my 22R in the -15V to -12V regulator.

I managed to get compression, meter was bopping, all seemed well. Then it started distorting more and more and soon after my 22R went up. I can't see any visible shorts.

I'll replace the 22R again and see if any setting of the compressor triggers the burning, or increase of voltage on the 22R. It doesn't seem to do anything when I first turn it on, when it's just turned on the voltage across the 22R reads around 0.2-0.4V, if I recall correctly. I'll measure it more when I have it running again. Any ideas? I'll attach some pictures.

https://imgur.com/a/xJbSVrZ

 

[weiss]

Okay interesting new development:

i resoldered all connections and now i got the following problem:

- either no sound comes through (regardless of bypass switch)
- or after some time all the lights just go out like that and then clean sounds gets through, without compression though

Am i looking into a voltage problem here ???
i probably should change the transformer to a toroid like olegarich already proposed... ?

 

[LolloTheMad]

Hello everyone, i just finished my GSSL and it works like a charm. I added a variable led meter and doubled the VCA section so i can choose between Gyraf and original mode. The only issue i have is something quite strange: when i turn the threshold almost fully counter clockwise there is a point where a ligh distortion rise up. The strange thing is that this distortion is not affected by any control, even the bypass switch can't take it off. I can hear it only with a 1kHz tone because the distortion is very very tiny. Any clue what could be the cause? thanks in advance, Lorenzo

 

[gyraf]

Check your +/-12V's while you turn the threshold, maybe it's a loading prob?

 

[joakimkarlthomas]

Was thinking of maybe build a new gssl and put it into a free space in my tascam m3500 mixing console and use the already existing power supply of the console. The console power supply’s got 15v +&-, and 12v+. (And 48v for phantom of course).

Not sure yet if the power supply of the m3500 will be able to handle such a mod yet. But if it does, is it right to put the 15v+&- on the the 15v+ and 15v- on the jumpers with this marking on the gssl main board?  And where should I load the 12v? Can I skip components on the gssl main board power supply section?

 

[Potato Cakes]

Was thinking of maybe build a new gssl and put it into a free space in my tascam m3500 mixing console and use the already existing power supply of the console. The console power supply’s got 15v +&-, and 12v+. (And 48v for phantom of course).

Not sure yet if the power supply of the m3500 will be able to handle such a mod yet. But if it does, is it right to put the 15v+&- on the the 15v+ and 15v- on the jumpers with this marking on the gssl main board?  And where should I load the 12v? Can I skip components on the gssl main board power supply section?

If you look at the schematic, you can see that only one bipolar rail is needed to power the unit as the other IC components in the PSU create the +/-12V. Provided the console PSU can handle it, I would would look at the instructions on the expataudio.com site for wiring a CRC PSU with a GSSL as that's basically what you're doing. If you are using an off board PSU, I would recommend omitting the 1000uF capacitors in the GSSL PSU section as this sometimes causes power up/latching issues.

Also, please refer further mods and questions that are not a stock GSSL build as per the assembly guide found on the PCB Grinder GSSL page (https://pcbgrinder.com/index.php?route=product/product&product_id=67) to the GSSL add on thread (https://groupdiy.com/index.php?topic=65232.0).

Thanks!

Paul

 

[Catrunes]

hey all, any idea why my unit would be distorting audio at the fastest release setting but all other are fine? comp sounds and works perfectly otherwise, just distorts at .1 release setting.