GSSL HELP THREAD!!!

[Harpo]

but i could test it only with 47Ω becasue i had no 51Ω Resistors...
do i have to change them or is it not so important?

..so your VCAs could be sufficiently adjusted by a max. +/-4.7mV trim range when you substitute the 51R with 47R in the formula above. Nothing to change for you.

 

[krabbencutter]

Attention:
This thread is an archive of possible and tried problems and solutions - NOT a help chat.
Try to go through this thread looking for answers before posting questions - that way there's a better chance someone will be happy to answer.

Just ordered the neccessary parts and will hopefully start building next week. Is there any efficient way of searching this topic? I'm all for "read first, ask later" but manually reading through 420 (!) pages is just not feasible for me :-X (fair enough tho, if that means it's not feasible for people to reply either)

 

[Script]

Switch to "print" view (top right) and search using "find in page" or search function of browser of your choice.

 

[krabbencutter]

Switch to "print" view (top right) and search using "find in page" or search function of browser of your choice.

Awesome, thanks a lot!
@Gyraf would you consider adding this info to the first page? Maybe something like

[...]Try to go through this thread looking for answers before posting questions - that way there's a better chance someone will be happy to answer.
If you switch to "print" view (top right) you can use your browser's search function to conveniently search through all posts at once.

 

[gyraf]

thanks - added to first post..

 

[r2d2]

thanks - added to first post..

threshold sensitivity variation rate with resistor

it could be an useful mod with a toggle switch and the resistor ?

peace

 

[Owenkellenberger]

Hello,

I have just started trouble shooting my first GSSL build. I have audio passing through the board and it sounds good. However, when I plug in the control board the audio drops out (or is considerably ducked) at seemingly random intervals. The power LED and meter show no activity except for when the audio drops the LED flashes and the meter swing. None of the switches/potentiometers seems to have an effect when turned. Has anybody encountered an issue like this?

My reading elsewhere on this forum make me wonder if it could be an issue with the 78L12/79L12 VRegs latching? They are quite hot to the touch.
78L12 I measured 22.9VDC in and 11.96VDC out.
79L12 I measured 10.5VDC in and 22.5VDC out.

Can anybody tell me if these values are incorrect?

Thanks so much!

 

[gyraf]

measurement on 79L12 is wrong - try again?

 

[Owenkellenberger]

measurement on 79L12 is wrong - try again?

Hi Gyraf,

Thanks for your response. Yes, I measured wrong. The 79L12 is putting out -12V and it appears that -12V is supplied everywhere that is required (including control pcb). The 78L12 is putting out the expected +12V until the control board is attached. When attached it is delivering ~2.5V in seemingly random pulses. I traced the +12V to it's end at the make-up gain pot. This connection seems to responsible for the loss in voltage/pulsing of the LED/audio ducking.

I'm stumped (at least for tonight) but it appears that my Ratio-Attack-Release switches are working the way you'd expect, but the side chain is responding to this pulse rather than my input signal.

 

[Script]

Check resistor values around pot.

Check for shorts around pot as well as around all connections between main and control board.

Jumper on control board is installed?

 

[Owenkellenberger]

Check resistor values around pot.
Jumper on control board is installed?

Hi Script, thanks! Jumper is installed. I've gone through and double checked all of the soldering on both boards and the resistor values. I traced the problem past the make-up gain pot. When I snip the "0" common wire going back to the main PCB the compressor works, but is super loud. So the issue seems to take place when +12 is sent to back to ground '0'.

 

[tyskstil]

Hi GroupDIY'ers,

I am in the process of sending the gerber files, kindly available from gyraf.dk, to production and I have a question:

Question 1:
The PCB in the gerbers are rev#7, and I am having an issue with drill hole size... The production facility dude sent me a mail stating there are issues with the drill hole sizes.

There is a document "Tools.txt" for the main board, which contains instructions for 6 different drill sizes, yet in the "Drill.exc" there are only drill coordinates for one drill size. As far as I can tell from PCBgrinder images, the main board has several different size holes. Does anyone know what is going on here?

EDIT: Okay, I just saw the "change to print view and search" advice above..... I will be looking through the thread in this manner and repose the question if I still have any doubts.

EDIT2: So I can tell that someone had the drill hole size issue earlier in this thread. For some odd reason, the drill file looks different for me if I view it using TextEdit (mac), or from the terminal using Vim. Of course, the Vim version is the correct one. I don't know exactly what is causing this issue, but I ended up trying to copy the text from Vim into a new text file in Vim, saving as "Drill.txt" and then manually changing its suffix to ".exc" instead. Now I have sent the new file to fabrication. We will see if it works.

 

[Owenkellenberger]

With further reading/testing, I think I am starting to get a clearer picture. My +12V line runs as expected with the control PCB disconnected. Once the control board is connected, the 78L12 heats up and goes into what I assume is thermal shutdown where it is putting out 2.5V in pulses. I have looked everywhere on the control PCB for shorts or bad/incorrect components and have found nothing. So looking at the schematic it seems that the only place left for a fault is in the sidechain section - post control PCB. Still I have not found any shorts or bad components, but I THINK I am getting closer

 

[Gustav]

With further reading/testing, I think I am starting to get a clearer picture. My +12V line runs as expected with the control PCB disconnected. Once the control board is connected, the 78L12 heats up and goes into what I assume is thermal shutdown where it is putting out 2.5V in pulses. I have looked everywhere on the control PCB for shorts or bad/incorrect components and have found nothing. So looking at the schematic it seems that the only place left for a fault is in the sidechain section - post control PCB. Still I have not found any shorts or bad components, but I THINK I am getting closer

Did you check the orientation of your 10 pin connector?

Did you check the wiring of your bypass/SC switching? (Maybe an error, especially if you are attempting to wire up the lit pushbuttons, which often causes problems).

Gustav

 

[gyraf]

..too much current drawn by the led attached? We've had that very problem several times already in this thread..

/Jakob E.

 

[Owenkellenberger]

..too much current drawn by the led attached? We've had that very problem several times already in this thread..

/Jakob E.

50R pots instead of 50K. I'm sure that would do it. Can't believe I overlooked that for 3 evenings of my life... On the up-side I learned a lot about all the things that aren't wrong with it ;D!

 

[gyraf]

 

[richtrix]

Hi Guys,

I bought my GSSL kit from PCB grinder in 2016. I had actually kind of forgotten I had it until I was cleaning out some boxes recently and found it. Lucky for me it appears that my past self had already populated the boards and all that was left was putting it in a box and all that fun stuff. So I bought a faceplate and SSL styled buttons and meter from DonAudio and over the past couple weeks finished putting it all together. I made sure that my Power transformer was reading correctly before I connected it as the last step. So I turned it on and nothing lit up but the Comp meter did peg all the way negative. No audio flowed through. I read the voltage at the meter as 10V and the voltage for power on LED at -2V. Obviously something was wrong so I looked for where there might be a problem with my assembly and I found it. My past self wired the ribbon of cables from the main board to the panel board exactly backwards. I fixed that and turned it on and everything lights up correctly now (except the meter light, maybe it needs other than 5V?). Still doesn't pass any audio though. Before I get in the weeds checking every resistor and looking for shorts etc I have 2 questions I thought I'd ask here. 1) are there any diagnostic diagrams available to check voltages at various locations?  2) Is it possible I have fried an IC or THAT 2080 by having that ribbon backwards? I am pretty sad it didn't just work after all the time past self and I put into it!

 

[gyraf]

reversing the cable to frontpanel usually doesn't make permanent damage..

check your IC types and orientations

check your voltages

follow signal through unit

/Jakob E.

 

[richtrix]

Ok Good to know it's hopefully not damaged. Is there a diagram that shows voltage test points? Everything looks fine as far as the 15VDC and 12VDC from the power supply. Also I saw you mention to another poster that the light up push button are often wired wrong. Those are what I have. I am pretty sure I did it right (though they stay all the time the way I have them wired right now) but what are the common errors made?

All my ICs are oriented correctly. I will triple check that they are in the right places.