GSSL HELP THREAD!!!

[Enchilada]

You guys... all legends!

I probably would have eventually just given up. It was a fairly silly noob mistake but I consulted the manual and I was using my multi incorrectly. Now voltages at all test points are perfect 

Can't wait to wire it up and give it a try now.

Thanks again, you guys have all been really helpful.

 

[artosaudio]

ok my relais input reads -15 volts and I only hear him click when i turn the gssl off in "in" mode. Why is it still in bypass. NO single control works! Is there something simple I can check to see if I can get it out of bypass...

Voltage nou reads 15.3/-15,3 after I found a short on the ssc board...

Help me...! ;D

 

[artosaudio]

Oh Just now I found out that the make-up gain works (only on the right channel) when in "in" mode. In bypass It does nothing. No threshold or whatever though...

 

[kante1603]

You guys... all legends!

I probably would have eventually just given up. It was a fairly silly noob mistake but I consulted the manual and I was using my multi incorrectly. Now voltages at all test points are perfect 

Can't wait to wire it up and give it a try now.

Thanks again, you guys have all been really helpful.

Yippee!

Udo

 

[artosaudio]

Oh Just now I found out that the make-up gain works (only on the right channel) when in "in" mode. In bypass It does nothing. No threshold or whatever though...

nobody?? :'(

 

[kante1603]

Oh Just now I found out that the make-up gain works (only on the right channel) when in "in" mode. In bypass It does nothing. No threshold or whatever though...

nobody?? :'(

Hi,
does the unit pass audio either switched in and out?
Are you sure you have wired the two boards correctly?Some members here reversed the flat-cable for example.If so the switches on the small board will not work because the vca(s) are not under control then(times,ratio etc.).
Concerning your Make-up:Have you followed this instruction?(see att. file)

Best,

Udo.

 

[artosaudio]

No the unit, does not pass audio when out... as for the makeup wiring, Since I have the ssc board things are wired a bit different, I'm pretty sure they are goed like this:

http://picasaweb.google.com/barclaycon/GSSLSuperSidechainPCB#5185516908667730034

I'm gonna check on the control wiring, maybe there's a little mistake there, also the threshold pot wiring, maybe a mistake there (probably not). The Gssl doesn't act differently wether I reverse the control wiring or not!

 

[MeToo2]

Does anyone know wich pin of the 24 v relais should get the voltage, I do not hear any click when turning on my gssl I read 2.30V on two pins wether it is in bypass or not, my gssl is in an eternal bypass mode so i sense a connection...
Oh this is the ssc board offcourse...

by the way is 17 volts to much for the main rail?

greetings thanx in advance!

Humbly suggest you help yourself out by posting some photos, and a clearer description of how and what you are measuring from where to where, and why you think that is a problem. A "my compressor doesn't work" type post won't help anyone to help you, which is probably why no-one has answered your questions. People on this board are generally very friendly and helpful if you give them the information they need.

There are many different types of 24V relays, and they have different pin outs and connection requirements.

There are also many different voltages in a GSSL, and many places to measure them, and relative to which point.

Component pin ID's are generally a help.

For example, you could ask: I measured between pin 8 of IC1 NE5532 on the SSC board and the 0V star ground using an auto-ranging multimeter on DC mode and it read +17.0 V DC . I expected to see +15V. Is +17.0V OK?

The answer would then be "no, that is not OK if there are chips inserted. Pin 14 should be regulated to 15V±0.6V by the 7815. 7815's are not great at regulating without a load, but once there's a load they should be within specification. Check your power supply."

 

[kante1603]

No the unit, does not pass audio when out... as for the makeup wiring, Since I have the ssc board things are wired a bit different, I'm pretty sure they are goed like this:

http://picasaweb.google.com/barclaycon/GSSLSuperSidechainPCB#5185516908667730034

I'm gonna check on the control wiring, maybe there's a little mistake there, also the threshold pot wiring, maybe a mistake there (probably not). The Gssl doesn't act differently wether I reverse the control wiring or not!

If I where you I would get all(!) add-ons/boards and relais disconnected and try to get the pure compressor working as it was originally.There seems to be a basic fault here.If things like ssc-board are hooked up and other stuff this "equation" will have too many variables in it.
E.g. you can then bridge the Inputs (after the debalancing-stage) to the Outputs (before the balancing-amp) to see if audio is passing in general,then go on to the vca(s),checking control-board connections etc.

Best,

Udo.

 

[Enchilada]

Another quick question for you guys. I've used THAT2181LA VCAs for my GSSL build. I've done all the modifications on this site - http://diy.fischerworks.com/gssl_vca.shtml. What I now want to know is how to I set the PCB mounted 50K trimmer to the correct value? What specifically does it do? At present I have it in the centre, do I need an oscilloscope to measure anything in order to set it up correctly?

Thanks,

Kris

 

[Harpo]

You will need a THD meter for adjusting to min.displacement/THD with audio signal present and VCA forced into bypass condition (Ec=0.000V). For the GSSL, designed for audio signal always running thru the VCA (not hardwire bypassing the unit), this bypass condition can be set with the bypass switch. Without a THD meter you might find the win.pc based RMAA Audiotester useful.

 

[Max51]

Hi all,

I'm new to this forum but I'm addicted for months. And today I managed to create a profile ! So it's a great day for me !

I finished a GSSl since few months but I have a little problem. When I turn on and  I turn off the gssl, I've got a big audio "plop" in the outputs and the vu meter made a big excursion.
I don't know if it's normal, I'm a newbie in electronics and I didn't found troubleshooting for this on that thread.
I tested all wiring and some components like regulators and capacitors, and I didn't found problem. I also test continuity in small spaces to exclude shortcircuits.
So if someone can help me, it would be great.

Thanks and sorry for my english

Max

 

[gyraf]

plops at startup and shutdown is normal and expected

 

[Holiveira]

I went over my problem. I could not see what the problem is.

I saw the 2180 datasheet and saw that the gain G = (Pin 2 - Pin 3) / 0.0061.

I decided to increase the tension in 2180 (sidechain), i lowers the R470 which connects to Pin 3 of  2180 in sidechain . And I got a result, now when I move the treshold I see the difference.


The tension in F: -0.55v > -12.3v

Does the problem is here...?

I read that the voltage should be 0.23v > -12v

thanks
Hugo

 

[Enchilada]

Hey again guys. Got my GSSL all wired up and going today. Passed audio first time so I was happy with that. Bypass switch seems to be working, the meter only dances when the switch is on and stops when it's off. The audio is noticeably quieter when compression is active. Ratios, attack and release seem to be working correctly.

The make-up gain, however, does not affect the volume very much. The threshold also is having problems. It doesn't seem to affect the sound at all and the meter doesn't change. I'm pretty sure I wired them up correctly but I will post pictures later and you guys can slam me if I've wired then up backwards. I put the 47K resistor as per the instructions so I'm thinking that's not the problem. I meticulously checked every resistor with my multi when I was populating the PCB so I don't think an incorrect value is my problem.

Any ideas???

 

[MeToo2]

I went over my problem. I could not see what the problem is.

I saw the 2180 datasheet and saw that the gain G = (Pin 2 - Pin 3) / 0.0061.

I decided to increase the tension in 2180 (sidechain), i lowers the R470 which connects to Pin 3 of  2180 in sidechain . And I got a result, now when I move the treshold I see the difference.


The tension in F: -0.55v > -12.3v

Does the problem is here...?

I read that the voltage should be 0.23v > -12v

thanks
Hugo

lowering the 470 is unlikely to help unless the wrong value for the 470R or 47R was there to start with.

Point F is a simple potential divider. min is -12v. If you move the pot to the other exteme it's Rpot/(Rpot+47k) * 24V -12V
So if if you want a slightly higher threshold then you could play with the 47K resistor at point F.

But I don't think that's your problem.

Sounds like your SC amp may be giving too much gain and acting more like a comparator, than a non linear amplifier.
You probably need to look earlier in the side chain for the problem.

Turn your attack time to fast and release time to slow.

Can you see your input signal on pin7 of the TL074 with theshold min and threshold max?

Can you see -ve spikes at point C when the input signal is loud, and otherwise 0V when the signal is quiet?

What about pin 10 of the TL074 = point O?: a spike negative which then decays over time?

Have you checked your tantalum caps in the side chain are the right way around?
And the 1n4148 diodes too?
What about checking the wiring of your ratio board?

 

[Holiveira]

Hi MeToo2,

I've checked the diodes and capacitors.... when I get home I'll check everything as you advice.

My problem is the following:

when I have the treshold in + 20 position, I dont have output or  with very low level (according to position attack and release).
I start to run treshold to the position -20, and does not work. when I have thresholds in the middle I start to have output (it looks like a switch) and I still run the treshold to -20 position and the volume will increase.

Voltage test:

F:

-0.5> -12.3

Pin1 TL072:

0.2> 3.23

I changed the R470 to R68ohm and worked well.
i Experiment, the exchange of 220K (between F and the Pin1 TL072) for 110K and also worked well,
(With treshold at position +20, does not compress when I run the threshold for the -20 position, it compresses.

sorry my english

Hugo

 

[Enchilada]

Back again after some more troubleshooting. It seems my makeup gain problem was related to not having soldered an LED on the control PCB. Output gain is working great guns not. Still having trouble with thresholds though and after some more testing, ratios don't really appear to be changing that much (very little audible difference between 2:1 and 10:1).

I read somewhere that I should trace DC voltage to pin 7 of the TL072. How would I do that? following the traces, if I'm seeing it correctly pin 7 leads to a 100K resistor, a 100pF cap, a 620K resistor then to pin 'E' on the cable to the control PCB. If that's correct I have 6.9V at pin E, 6.9V at one side of the 620K resistor and 0V on the other. Measuring from pin 7 I get 0.11V or between 0.7V and 0.9V when music is playing.

Tested for a cold solder joint and that can't be the case because if I measure at the leads of the 620K resistor I get the same result.

Any ideas?

 

[artosaudio]

First of all, thank you all for you replies, if it wasn't for this place I wouldn't have finished anything yet i think...

Because I had done so much desoldering and resoldering on my main pcb i decided to make a new one (I started to get irritated by the "look and feel" of the board.) While I was at it I decided to make a new control pcb too..

so after hooking up things didn't work out as expected (again) now something strange happens, when I put in a sine louder  then -12db I get a totally distorted clipping signal back. When I lower the input the output is softer then the input and clean, as for the rest, no controls no nothing...

tomorrow again troubleshooting day I guess... :-\

Must be some wiring issue but I double checked everything so many times allready...

 

[Enchilada]

Here's are some images of how I wired up the makeup gain and threshold. I'm pretty sure I did it correctly.

http://imageshack.us/photo/my-images/696/20111102213558.jpg/
http://imageshack.us/photo/my-images/403/20111102213548.jpg/

These are the pots I'm using http://www.jaycar.com.au/productView.asp?ID=RP3516

After a little more reading, I think I should be testing pin 7 on the TL074, not the TL072. I'll do that after work and report back