GSSL HELP THREAD!!!

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1wildthing

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Jan 27, 2021
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Gustav
I’ve tried to compare the behavior of my gssl to the waves plugin in order to understand the differences. Threshold wise from the center scale to full CCW the behavior is similar and even the meter reacts in the same way.
Your unit should not react when threshold is set above audio level - there is no "compressor to one side/expansion to the other" functionality, only compression over the set threshold.

Sounds like you have something weird going on, but we would need feedback on what happens to help.

Gustav
Your unit should not react when threshold is set above audio level - there is no "compressor to one side/expansion to the other" functionality, only compression over the set threshold.

Sounds like you have something weird going on, but we would need feedback on what happens to help.

Gustav
Ok Gustav I’ve tried to compare the behavior of my gssl to the waves plugin in order to understand the differences. Threshold wise from the center scale to full CCW the behavior is similar and even the meter reacts in the same way. However when the pot moves from the center to the right in CW direction the meter immediately goes to 0, the compression disappears and bypassing the effect the sound is the same. Moving threshold pot even to full CW makes no difference and even on hard settings of other knobs the sound doesn’t change.
I’ve tried to replace the threshold pot but nothing has changed.
Any idea?
 

Gustav

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Ok Gustav I’ve tried to compare the behavior of my gssl to the waves plugin in order to understand the differences. Threshold wise from the center scale to full CCW the behavior is similar and even the meter reacts in the same way. However when the pot moves from the center to the right in CW direction the meter immediately goes to 0, the compression disappears and bypassing the effect the sound is the same. Moving threshold pot even to full CW makes no difference and even on hard settings of other knobs the sound doesn’t change.
I’ve tried to replace the threshold pot but nothing has changed.
Any idea?

I dont know which plugin you are comparing to, or what it does exactly, but as I understand it, you have an expansion of some sort going on when using the plugin, and you are lacking that on the hardware unit.

The hardware unit you have built is a compressor. When you move the threshold, you set the threshold for the desired amount of compression relative to the amplitude of your program material. When you move the threshold above that amplitude, no compression will occur.

On your first post, I misread and thought you had something going on when moving the threshold out of the way. The fact that you dont just means the unit is working as expected.

Hope that helps!

Gustav
 

1wildthing

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I dont know which plugin you are comparing to, or what it does exactly, but as I understand it, you have an expansion of some sort going on when using the plugin, and you are lacking that on the hardware unit.

The hardware unit you have built is a compressor. When you move the threshold, you set the threshold for the desired amount of compression relative to the amplitude of your program material. When you move the threshold above that amplitude, no compression will occur.

On your first post, I misread and thought you had something going on when moving the threshold out of the way. The fact that you dont just means the unit is working as expected.

Hope that helps!

Gustav
Ok I understand but I’ve also tried to change the input volume of the sound source in order to see how this affects the compression but don’t matter the input level when I move the threshold from the center to CW nothing happens on the sound and the meter immediately stops to move. I’ve tried a really hot signal input as well as cold signal and It doesn’t make any difference. This is the thing that seems weird to me. It’s like something stops the circuit when the pot moves on the right part of the voltage divider. The only thing that keeps on working is the gain pot.
 
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gyraf

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There is perhaps some misconception of the way it works? Why would you expect the compressor to react at threshold pot fully CW?

turning threshold all way up equals turning all way down for the signal-to-sidechain - threshold value here is somewhat higher than +20dBu, in effect bypassing the compression

if you for some reason WANT to have a reduced range of threshold, just put in a resistor in series with one of the ends of the potentiometer

/Jakob E.
 

1wildthing

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up equals turning all way down for the signal-to-sidechain - threshold value here is so
There is perhaps some misconception of the way it works? Why would you expect the compressor to react at threshold pot fully CW?

turning threshold all way up equals turning all way down for the signal-to-sidechain - threshold value here is somewhat higher than +20dBu, in effect bypassing the compression

if you for some reason WANT to have a reduced range of threshold, just put in a resistor in series with one of the ends of the potentiometer

/Jakob E.
Sorry guys it was my fault. I found another faulty solder joint. Now it works! Time to start the super side chain board. Thanks for your help!!!
 

1wildthing

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Hi everybody, please forgive me, unfortunately I'm here once again asking for you help.
I've finally finished my build (Basic board mounting THAT2181BL+PCBG Super side chain board + pushbuttons for power and bypass) but once I've connected my gssl in the studio I've realized that something is not working well with it. :cry:
I've experienced a nasty distortion on the input stage. If I feed an 0 db audio signal the unit goes mad on distortion. I have to bring a really cold signal (-25 db) to prevent the unit to distort. The overdrive still remains even in bypass mode and is equal on both channels.
When I push down the input level, the sound of the unit is amazing but, being the output level really low as well,I need to reamp it through my soundcard preamps bringing up a wicked noise floor.
To be honest I didn't make a serious test of the GSSL before adding the SSC Board so I don't know if the problem depends on it.
In this thread I've seen another guy having a similar problem but I wasn't able to find the solution.
Does anyone has some ideas on what happened or what I need to check first?
 

Gustav

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I've experienced a nasty distortion on the input stage. If I feed an 0 db audio signal the unit goes mad on distortion. I have to bring a really cold signal (-25 db) to prevent the unit to distort. The overdrive still remains even in bypass mode and is equal on both channels.

First, I would try to determine if there is a problem with the unit, or if the signal is simply too hot.

To do that, we need to know the voltage coming into the unit. Your dB references are empty. (assuming dBFS) without context, so they do not help.

Let us know the actual voltage or dBU reference (if you are unclear on this, let us know, and we will help).

Gustav
 

1wildthing

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First, I would try to determine if there is a problem with the unit, or if the signal is simply too hot.

To do that, we need to know the voltage coming into the unit. Your dB references are empty. (assuming dBFS) without context, so they do not help.

Let us know the actual voltage or dBU reference (if you are unclear on this, let us know, and we will help).

Gustav
Thanks Gustav. Yes I can confirm that dBFS was concerned, measured on output channel by the software monitor of my soundcard. To be more precise the output channels of the soundcard are settled on -10dBV and the channel shows a peak level of -17 dBFS on monitor.
Could you please tell me at which point I have to measure the Voltage? May be AC Voltage on hot pin of the XLR inputs? Or DC voltage elsewhere?
Thanks for your kindness and please forgive me for my noob questions.
 

Script

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AC on pins 2 and 3 of input XLRs .
Then AC at output pins of 'input ICs'.
Then at inputs and outputs of 5534 buffers before VCA.
Then at VCA in and out pins.
Then at inputs and outputs of 'output ICs'.
 

Blondino

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Hi there... stupid question: there is a video somewhere about all those AC measurement? especially with current? sometime I'm worry to touch the wrong spot and bridge something!
thanks
 

Gustav

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Hi there... stupid question: there is a video somewhere about all those AC measurement? especially with current? sometime I'm worry to touch the wrong spot and bridge something!
thanks

You wont hurt anything by bridging the pins on the XLR, so start there, try.

Gustav
 

1wildthing

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Hi everybody! Unfortunately I'm having some problems in getting correct measurement with my multimeter. When I try to measure AC voltage on XLRs using red lead on pin 2 or 3 and the black one on ground I get 0V. The same happens with red on 2 and black on 3 or vice versa. I get some values only when I use only the red one alone. Probably my multimeter has gone or is not able to read those values.
In meantime I've looked at noise floor using a spectrum analyzer and I've seen that the buzz I heard has a peak on 100hz and another one on 200hz. Maybe this one is the real problem?!?
Reading through this thread many people solved a similar problem using a CRC board. Do you think this could be for my case? I attach the spectrum analyzer screenshot. For this analysis I disconnected input XLRs.
 

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Gustav

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Hi everybody! Unfortunately I'm having some problems in getting correct measurement with my multimeter. When I try to measure AC voltage on XLRs using red lead on pin 2 or 3 and the black one on ground I get 0V. The same happens with red on 2 and black on 3 or vice versa. I get some values only when I use only the red one alone. Probably my multimeter has gone or is not able to read those values.
In meantime I've looked at noise floor using a spectrum analyzer and I've seen that the buzz I heard has a peak on 100hz and another one on 200hz. Maybe this one is the real problem?!?
Reading through this thread many people solved a similar problem using a CRC board. Do you think this could be for my case? I attach the spectrum analyzer screenshot. For this analysis I disconnected input XLRs.
Revert the unit to stock - see if it works!

Gustav
 
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I just built my GSSL with the dbx 202c with Expat turbo and I love how it sounds.

But I have a problem with the ratio control. By setting the knob to 2: 1 the compressor compresses 10: 1 and vice versa also 10: 1 is 2: 2. It is very strange I have checked the connections of the control panel and the Expat turbo everything seems correct.

I use Pusherman's rev 7 PCB.

I also take the opportunity to ask, I would like to equalize the unit gain of the compressor to be able to do a real bypass. The compressor loses about 3 db when connecting it, where could I put some trimpots to regulate the GSSL output, also maybe I could equalize the difference of 0.2 dB between L and R.

thank you very much for your help
 

Script

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Check ratio wiring again for correct connectivity of both SC channels. If that doesn't fix it, you need to trace side chain signals.

On a vanilla GSSL, the 15k or 27k resistors feeding the VCA IN are a good spot for a unity gain trimmer. Not sure what your VCAs need though.
 
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elación nuevamente para verificar l
Check ratio wiring again for correct connectivity of both SC channels. If that doesn't fix it, you need to trace side chain signals.

On a vanilla GSSL, the 15k or 27k resistors feeding the VCA IN are a good spot for a unity gain trimmer. Not sure what your VCAs need though.

Do you mean these?
 

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