GSSL add-on help thread

[gyraf]

could be as simple as resistor tolerances around the current-to-voltage opamp section?

..if 0.3dB bothers you (I wouldn't care), add a small trimmer resistor in series with the gain setting resistor (the feedback on the opamp following the vca)

/Jakob E.

 

[craigmorris74]

could be as simple as resistor tolerances around the current-to-voltage opamp section?

..if 0.3dB bothers you (I wouldn't care), add a small trimmer resistor in series with the gain setting resistor (the feedback on the opamp following the vca)

/Jakob E.

Thank you very much for your reply, Jacob! And thank you for your work making this project possible.

I was thinking about a trimmer, but wasn't sure where to put it. This will be an easy fix.

 

[LB82]

Hello everyone, this is my first post here

I have a Radioman bus compressor, I think it's basically a GSSL. I'm looking for someone that can make mods to it (turbo/Oxford mod and eventually others).
I have no electronic/soldering skills, I can barely solder cables, so I'm looking for someone that I can send my Radioman to and then get it back modded.
I'm located in central/northern Italy and I'm looking for people in Europe for easy shipping.

Any suggestions of good technicians that make this kind of works is welcome, many thanks

 

[lauritz]

Hi All

I'm working on a GSSL with a single SSC board and the turbo board. I'm hooking it up so that it'll run in either turbo mode or gssl+ssc mode. My question is whether i can leave the return from the SSC board connected to the return on the Gssl board at all times without any problems?

I wanted to break the connection when switching to the turbo mode (ON), but i only have a 3pdt switch avaible for the switching, so i thought that maybe the return connection from the SSC could be left connected, without any problems. Maybe noisefloor will be raised slightly i'm thinking...other complications to take into account? No audio is being fed to the SSC board when the turbo mode is engaged

I'll get the proper switch eventually, but i want to have it up and running for a mix-session soon to come

all the best, Lauritz

 

[Script]

Shouldn't be a problem as the junction where the CV signals meet makes the 'higher' of the two signals drive the VCAs, I think. When no signal into Turbo, then no signal from Turbo...

 

[desol]

I think someone should make a new PCB that incorporates all the add ons for the GSSL.

A new board instead of having all these add on boards, etc.

 

[innercityman]

I think someone should make a new PCB that incorporates all the add ons for the GSSL.

A new board instead of having all these add on boards, etc.

Serpent Audio and DIY-Racked do this already... Make a search.

 

[timtom]

Are the CRC filter boards for the GSSL still for sale somewhere?

 

[Script]

GSSL CRC PCB | expataudio

When adding shipping, import tax and customs processing, it'll cost you though.

Basically it's a bridge rectifier followed by filter caps. Could google CRC filter for inspiration.

And some say, it's not even needed when unit is built right.

 

[gyraf]

..agree. CRC is not at all necessary..

 

[living sounds]

..agree. CRC is not at all necessary..

Yes, I think it's more important to make sure audio ground gets its only connection to chassis ground via the PSU. This should eliminate hum and also RF getting into the circuit.

 

[timtom]

GSSL CRC PCB | expataudio

When adding shipping, import tax and customs processing, it'll cost you though.

Basically it's a bridge rectifier followed by filter caps. Could google CRC filter for inspiration.

And some say, it's not even needed when unit is built right.

It is out of stock...

..agree. CRC is not at all necessary..

My personal GSSL is without it and built with high quality components and good skills. At the moment I'm repairing/ modding one for a friend that is noisier then my unit. But the build quality isn't that great.

 

[huuubert]

Hi all!

My gssl is fully operational except in turbo mode where the Vu Meter becomes crazy. The video below shows the issue with no signal, no cable inserted, only the power source.

View attachment VID_20220607_222520.mp4

If someone may have an idea to solve this issue....

 

[craigmorris74]

My GSSL with Turbo board had been working flawlessly for several months, but upon running a mix through the unit last night, my stereo balance was ways off.

I ran a 1k tone through the unit, and one side is compressing considerably more than the other. I standard mode, the compressor works and each side compresses evenly, but the meter is showing much less compression than I would expect. The compression level of both channels is the same as the channel that is compressing less when in turbo mode (I'm only getting 4dB of compression, even with the threshold almost all the way down.

Swapped the THAT chips and get the same result.

I've read this thread, and noticed Script had a similar problem that resulted from blown diodes. Will check that tonight.

I keep reading about Keith's troubleshooting guide. Could someone direct me to that?

Thanks,
Craig

 

[Script]

Keith's GSSL troubleshooting guide. Post #6 in this thread:

Turbo Gssl help please..

Hi All, is there a copy of the silk screen for the pcb, just so i can make sure the resistors are correct, im sure they are but need to eliminate. i have a slight problem, the gssl only compresses from the right channel. when pluging only the left ch in , no compression can be achieved. I...

groupdiy.com

You mean this one ? Had to use search function 'Keith' (this thread) myself to find it

 

[craigmorris74]

Keith's GSSL troubleshooting guide. Post #6 in this thread:

Turbo Gssl help please..

Hi All, is there a copy of the silk screen for the pcb, just so i can make sure the resistors are correct, im sure they are but need to eliminate. i have a slight problem, the gssl only compresses from the right channel. when pluging only the left ch in , no compression can be achieved. I...

groupdiy.com

You mean this one ? Had to use search function 'Keith' (this thread) myself to find it

That's it. Thanks!

 

[craigmorris74]

Did Keith’s tests and got some atypical results:
with no signal applied: tl074 pin 1: -0.17VDC main board -0.14VDC turbo
no AC, DC on pin 8 varied with threshold

1v signal applied: 5534 outputs both 2.7VAC
TL074 pin 7-no AC on either
TL074 pin 1-no Ac on either, -0.13VDC main, 0.12VDC turbo
TL074 pin 14-no AC on either, 0.19VDC main, -0.52VDC turbo, threshold only changes turbo VDC
diode before point C: -1.17 main, -1.33 turbo

a bunch of weird measurements, not sure where to start troubleshooting.

 

[Gustav]

Did Keith’s tests and got some atypical results:
with no signal applied: tl074 pin 1: -0.17VDC main board -0.14VDC turbo
no AC, DC on pin 8 varied with threshold

1v signal applied: 5534 outputs both 2.7VAC
TL074 pin 7-no AC on either
TL074 pin 1-no Ac on either, -0.13VDC main, 0.12VDC turbo
TL074 pin 14-no AC on either, 0.19VDC main, -0.52VDC turbo, threshold only changes turbo VDC
diode before point C: -1.17 main, -1.33 turbo

a bunch of weird measurements, not sure where to start troubleshooting.

If you need help, try to give a little more context. Checking back to Keiths guide is more than most would be willing to do, so you can say

Did a set-up like this____

For A, x is expected, but I got y" etc.

Not sure if it will help, but it might!

 

[craigmorris74]

If you need help, try to give a little more context. Checking back to Keiths guide is more than most would be willing to do, so you can say

Did a set-up like this____

For A, x is expected, but I got y" etc.

Not sure if it will help, but it might!

Gotcha, just to reiterate problem is different levels of compression on left and right side when in Turbo mode.

To elaborate on the problems when doing Keith's test (which is the suggested course of action for troubleshooting the Turbo mod):
tl074 pin 1: -0.17VDC main board -0.14VDC turbo-with no signal, expecting 0V. Should I have disconnected the inputs?

When applying 1VAC signal, I got no VAC on pins 1, 7 and 14 on the TL074's. The guide says there should be AC here.

When applying 1VAC signal, VDC at pin 14 of the TL074 only changes on the Turbo board when adjusting the threshold. Expecting both to vary when changing threshold.

 

[craigmorris74]

Testing the unit right now, and here is something I can't explain: when applying a 1k tone to the left channel, I get a 0.8VAC coming to pin 1 of the main board VCA. When appying voltage to the right channel, I measure 0 VAC going to to the Tubrbo board VCA pin 1 get nothing. There is something coming out of the 47k resistor feeding it, because when I turn Turbo off, I get a voltage coming out of that resistor.