GSSL HELP THREAD!!!

[gyraf]

- The voltage regulators come with some tolerance, allow at least +/-5% before worrying

- Negative supply at the VCA's is through a resistor (see schematic), so you can't measure it at the VCA's minus-supply pin (we've discussed this before)

 

[MiamiBoy]

Meter LED
So I have 3 places that I can connect the LED's for my meter. I wanna choose the best option.
Which one do you recommend and why?

The 3 places are:
AUX via 7812
Left SSC or
Right SSC

 

[gyraf]

aux - you don't wanna disturb the 12V reference lines

 

[MiamiBoy]

aux - you don't wanna disturb the 12V reference lines

Perfect I’ve just installed the 7812 regulator.
Do you mean not to disturb the 15V reference line on each SSC board? Or the 12V from the 7812/aux?

 

[gyraf]

the +/-12V from the 78L12/79L12 should be kept clean, they are voltage references for VCA's

/Jakob E.

 

[MiamiBoy]

I have a 7815 and a 7915. I'm not messing with those. But they regulate power down to 15v and not 12v !?
Or am I totally off here?

I've added a 7812* recently, so it could add some voltage to the AUX (aux doesn't work without the 7812*).
It says it's *Optional* for RELAY & LIGHT. Pcb revision 11.

But adding the 7812*, and using AUX for meter-LED, is that gonna mess with the VCA's (7815/7915)?

 

[MiamiBoy]

The question is, which connection will make more sense to use:

• one of the SCC boards, that's already hooked up with resistors (2x 1K2) & ready for a meter-LED connection or
• install the 7812* and use the AUX with a resistor?

Obviously I'm looking for the option that's most gentle for the GSSL, which causes less damage, power wise.
I don't mind doing the extra work, whatever that might be. I want the best option for the long run.

 

[LNS]

18 months ago, I picked up a GSSL PCB, stuffed it, wired it and put it in a don audio case but I never got around to powering it up and finishing it. This weekend I had a spare afternoon so loaded the IC's and switched it on.

It powered up fine but none of the controls on the front work, I ran a test tone through it which makes it way to the outputs when bypassed or with the compressor switched in but there is absolutely no compression and none of the pots or switches do anything.

Before installing the IC's I measured the voltages at all the IC sockets and everything tested ok with the 15v IC's measuring -14.66v / +15.10 and the 12v IC's measuring -12.1v / +12.1v. However, the socket for the side chain 2180 measured -8v / 12.10v which is not what I was expecting from looking at the schematic.

I’ve checked all my soldering and can’t see any bridges; all components are correct and all wiring seems to be correct. I’ve obviously missed something but can't figure out what...... any ideas or suggestions of where / how I should start troubleshooting?

I’ve amalgamated a folder of pictures, schematics and guides of other people’s builds over the past 18 months and scoured this thread but can’t figure out what’s wrong with my build

 

[bundy]

Have you jumpered the "HPF" location?
I can't quite tell from the pics.

 

[LNS]

Have you jumpered the "HPF" location?
I can't quite tell from the pics.

Good spot, I hadn't but I have just soldered a jumper across.

Unfortunately I still have the same problem, audio is passing through fine but no compression and none of the controls are working still.

 

[Ricardus]

I would start checking the ribbon cable between the two boards, and the control board itself for any issues.

 

[MiamiBoy]

I think the ribbon cable is the issue.

I read from someone else with the exact ribbon cable as yours that was the guilty one. Those cables can be weak. He exchanged it to a better and more expensive cable and problem was solved.

 

[LNS]

I've tested the ribbon cable / connector / PCB's for continuity with a DMM and everything buzzes out as it should.

The only thing that I can't get my head around is C and 0 seem to be connected on the main PCB somewhere? I've tried to find them on the schematic to trace them but I can't figure out where they are?

I've also gone back and checked all wiring on the bypass switch as I thought that might be the issue but that is exactly the same as the wiring diagram I have.

Where do you guys think I should start looking next?

 

[MiamiBoy]

So both pcb-boards have continuity between each other via the ribbon cable.
Im not sure if that diagram you've attached is working properly.. I think that I once tried that wiring like your drawing and it didn't work for me. Especially the LED's were always ON in my case.
Try a simplified version without connecting both pushbuttons to each other, as intended in the original gssl schematic.

Don't worry about the LED's for now. Disconnect those and try only to connect the bypass button, separate from the power button and leave the LED's out for now.

 

[Harpo]

The only thing that I can't get my head around is C and 0 seem to be connected on the main PCB somewhere? I've tried to find them on the schematic to trace them but I can't figure out where they are?

I've also gone back and checked all wiring on the bypass switch as I thought that might be the issue but that is exactly the same as the wiring diagram I have.

C and 0 should not be connected (in between C and the attack-switch is one half of the bypass switch).
Your wiring diagram is either missing the connection in between E and the wiper connection to the makeup pot (the two dots right next to the 750k resistor) thru the other half of the bypass switch or a jumper instead for gssl-bypass with makeup gain still operating.

 

[MiamiBoy]

.

Hey Harpo, welcome back.

Would you mind looking at my question up there?
Jakob hasn’t answered it. It has caused more confusion unfortunately.

 

[LNS]

C and 0 should not be connected (in between C and the attack-switch is one half of the bypass switch).
Your wiring diagram is either missing the connection in between E and the wiper connection to the makeup pot (the two dots right next to the 750k resistor) thru the other half of the bypass switch or a jumper instead for gssl-bypass with makeup gain still operating.

Thank you, everything is now working on the control panel as it should

I found this diagram below online which helped me get it wired up properly, the last thing I have to iron out is getting the LED on the bypass button to turn off when bypassed.

I've been trawling through this thread today and have read I need to use a relay but I have no idea how to wire it and can't find any diagrams. There is an old post from potato cakes with a link to a diagram but the link isn't working and takes you back to page 1 of the GSSL HELP THREAD!!!

I will be adding a super side chain board to this build but I want to get it all functional vanilla with the push switches (and LEDs) all working before I start work on that.


Thanks for all the help!

 

[bundy]

I have a 7815 and a 7915. I'm not messing with those. But they regulate power down to 15v and not 12v !?
Or am I totally off here?

I've added a 7812* recently, so it could add some voltage to the AUX (aux doesn't work without the 7812*).
It says it's *Optional* for RELAY & LIGHT. Pcb revision 11.

But adding the 7812*, and using AUX for meter-LED, is that gonna mess with the VCA's (7815/7915)?

The 2 big regulators:
- The 7815 regulator provides +15V DC
- The 7915 regulator provides -15V DC

The 2 smaller regulators:
- The 78L12 regulator provides +12V DC
- The 79L12 regulator provides -12V DC

Then, there is another OPTIONAL regulator you can install if you would like another +12V DC voltage rail (to use for things like relays and lamps).
i.e. You can get +12 V DC without interfering with the previously mentioned 78L12 regulator.

 

[Harpo]

Hey Harpo, welcome back.

Would you mind looking at my question up there?
Jakob hasn’t answered it. It has caused more confusion unfortunately.

Context. IIRC you use two Barclaycon supersidechain filterboards with total 4 NE5532 dual opamps supplied by +/-15VDC (2x4x typ.6mA=48mA) and a relay with a 24VDC 2k8 coil and 200R resistor in series (+/-15VDC supply=30VDC/(2800R+200R)=10mA). Your two pushbutton switches come with built in LEDs and external 2k2 current limiting resistor (15VDC- depending on LED colour maybe 2VDC LED forward voltage)/2200R=6mA each) and your gain reduction meter comes with IIRC a 2 white LEDs in series backlight and two external 1K2 current limiting resistors ((15VDC-2* 3.2VDC fwd)/(1200R+1200R)=3.6mA). This additional total load is about 80mA. For these you don't need the optional 7812 voltage regulator. The GSSL on-board 7815 and 7915 voltage regulators will handle this. Maybe add a heatsink to each vreg if so needed.
Using different pushbutton switches with built in incandescent lamp, for instance EAO switch with T5.5 12V lampmodule, drawing 100mA per switch, a different 12VDC coil DPDT relay or a GR meter with incandescent backlight, the optional 7812 vreg would better be used for these power hogs.
As always YMMV.

 

[MiamiBoy]

I am only talking about the OPTIONAL 7812 regulator.

I have installed the 7812 and added heatsink to it and also heatsink to the other two regulators.
Sound like I don't need the 7812. So I should remove it again and use my SSC instead to power up the LED's?
(1 pushbutton will be powered by the ControlBoard). Both buttons are blue LED, meter is white LED.

So if I understood this correctly, it's better to draw my meter-LED power from SSC instead from the optional 7812 regulator, yes?

See attachment, this is how I'm planning to wire my LED's and SSC.

And thank you so much for doing the math.