GSSL HELP THREAD!!!

[MikeFFG]

Hi...I remember reading I'm supposed to clip a pin off of one of the switches..I seem to remember it being the Release switch maybe??  I know it's on this site somewhere but I've searched and searched and cannot remember where I read it.  Can anyone let me know or point me in the right direction?

 

[regularjohn]

I've built alot of these and I've never clipped a pin off anything.

The release rotary switch must be adjusted for five positions, if that's what you're thinking of.

 

[nickeveslage]

I think you'll find what you're looking for in regards to the switch 'modification' at this page, about half way down.

http://gssl.rolandklinkenberg.com/english/2.html

Couldn't be any easier. Hope that's what you were looking for!

 

[MikeFFG]

ahh yes that is what I was referring to.  Thanks!  I've read so many pages in the last week I can't keep all the info straight!

 

[artosaudio]

Artosaudio, if your meter reacts while turning the threshold knob and you've got no audio running through the comp, or if it overreacts while you have audio running through the comp, you likely have a problem with one of your power rails shorting to ground.

The ONLY voltage measurements that matter on any of the opamps are the voltage rails (+/-15 and +/-12) on the appropriate pins.  All other pins are subject to change depending on the audio (or lack of audio) running through the comp.

thank you so much, I think I'm heading the right way now. I've found a short on one of the ne5532's however problem is still not solved. In bypass the problem remains the same and in "in" my meter goes all the way no matter what i do!

I've checked with and without the supersidechain board so I assumed that the problem was in the main board!

If something jumps to mind please let me know! thanx

 

[artosaudio]

And now, al of a sudden. I have +8 and -0.1 on my main rails. Toroid is ok, so are my 7915/7815 faulty?

 

[artosaudio]

my bad that was not true...

now as soon as i turn on the gssl no matter it is in bypass or not the meter slams to max gr. no sound on left channel, normal sound ons right. There really is something seriously wrong.

I get around 10 volts on pin 14 of the tl074, seems a little bit much doesn't it..?

anyone for a suggestion, I'm about to throw it aside :-\ 3 days of troubleshooting in vacation is getting on my nerves...

anyone :

 

[mac]

Hey Arto
dont give up. But if you are at that point of frustration, sometimes walking away for a bit to clear your head is the best advice.

I am finishing up mine at the moment, and the other night started getting relly frustrated as I couldnt get it to pass audio. I was convinced that it was an issue in the input stage, and started pulling components off the board to check them and everything.

Went to bed annoyed. Next morning with fresh eyes, I realised I had been trying to find a fault that wasnt even there.

I hadnt grounded the inputs and outputs, and my test signal lead was faulty.Thats is all it was....

So walk away. Come back with fresh eyes, and start with all the basics to check everything. Dont assume your multimeter is working fine, dont assume all your test leads are good.


Good luck - you will crack it - and that feels great when you do!!

Mac

 

[MikeFFG]

I'm having trouble figuring out which direction to mount my Release switch in...I know there is a picture in the original SSL schematic PDF but the lettering is pretty covered up and I can't tell what it's saying.  I think I figured out the other two switches (though those weren't very clear either) but I totally can't tell with this one.  Any help?

 

[mac]

If it is an alpha or lorlin type going straight into the control board, it shouldnt matter as they can rotate 180 degrees and still work correctly. Just depends where you put your stop pin for the five positions.

Mac

 

[artosaudio]

thanx mac for the inspiring words, I'll will give it another try today with fresh eyes!

cheers!

 

[artosaudio]

I've been solderchecking almost all day. I really cannot find anything suspicious. When I throw in a testtone all I'm getting is audio on the right, left nothing, no controls nothing! meter says I'm slamming it ;D

???

 

[Biasrocks]

When I throw in a testtone all I'm getting is audio on the right, left nothing, no controls nothing!

Make a signal tracer and find out where your signal is disappearing.

http://www.diyfactory.com/data/mbsignaltracing.htm

Mark

 

[regularjohn]

I've been solderchecking almost all day. I really cannot find anything suspicious. When I throw in a testtone all I'm getting is audio on the right, left nothing, no controls nothing! meter says I'm slamming it ;D

Disregarding the audio passing or not passing, does the meter react in the same way when you test each channel individually?
If it does, then you can at least rule out the input section and the sidechain section.

 

[artosaudio]

yes it does, even with no audio at all! makes no difference, so probably the output section or one of the vca's?

I have +15 volts ac on pin 7 of the 5532 output opamp

that's not good, is it?

 

[beatnik]

where can i find schematics for gssl mods, super side chain and turbo mode?
all the links i have founded are dead...

thanks in advance

 

[regularjohn]

I have +15 volts ac on pin 7 of the 5532 output opamp

A 5532 should have +15 on pin 8.  There's something very wrong if you have it on pin 7, which is an output.

where can i find schematics for gssl mods, super side chain and turbo mode?

Supersidechain and turbo schematics are not available anywhere, as far as I know.  If you want the circuit you'll have to buy a pcb and trace it manually.

 

[artosaudio]

yes i know, but I'm talking ac here! isn't that a little but to much for some audio current?

 

[artosaudio]

Could explain the HUGE output offcourse!

 

[Harpo]

yes it does, even with no audio at all! makes no difference, so probably the output section or one of the vca's?

I have +15 volts ac on pin 7 of the 5532 output opamp

that's not good, is it?

Maybe broken VCA, but
check it step by step. If one step fails, fix it before continuing.

Make sure, all supply rails +/-15V and +/-12V are working. Case not, power down, pull all VCAs and opamps to exclude that a broken chip is shorting a rail or drawing too much current. Power up and check again after refitting each chip one by one.
A voltage regulator might be hanging on startup. Using a different brand most often helps. A diode between regulator output and 0V, anode side to the lower voltage rail (0V for the positive rails regulators or -12V/-15V for the negative rails regulators), might fix this latching as well.

If you plan or already have connected a turbo board or sidechainfilter board, temporary disconnect this/these and refit both 47K resistors, feeding the gssl sidechain.

Feed both gssl inputs with same source, maybe from a keyboard or frequency generator, level set to about 0dBV (1V RMS, 1.414V pk), frequency set in range of 100 ... 400Hz to allow a more reliable measuring with a cheap meter that won't measure higher frequency testtones.

Input stage: Measure both outputs of the line receivers, NE5534 pin6. They should measure the same 1V AC. Case not, check for shorts, same 22K resistor values or replace the broken opamp.

Output stage: Power down, pull both audio VCAs and temporary link pins 1/8 with a piece of wire to bypass the audio VCAs. Power up again and measure both NE5532 pin7. With 27K in front of the VCAs and 15K feedback resistors (ideal value would be 2x27K in parallel) both should measure about 0.55VAC. Case not, check for shorts, correct resistor values or replace the broken chip.
This same voltage should arrive at the bal.out + molex connector. Case not, mend the broken trace that interrupts signal flow.
Next measure both NE5532 pin1 for same value but inverted phase voltage reading as at pin7 of the same chip. This same voltage should also arrive at the bal.out - molex connector, ie. measuring between +/- bal.out giving a 1.1VAC reading (or 1VAC with prementioned feedback resistors half the value of the resistors in front of the VCAs).
The audio path now should be working, except an audio-VCA is broken or has wrong resistor values connected, but still keep the bypass link instead of the audio VCAs for now.

Sidechain: Reduce input level to -20dBV (0.1V RMS, 0.14V pk).
Power down, temporary disconnect the meter showing gain reduction, pull the sidechain VCA and temporary link pins 1/8 with a piece of wire to bypass this VCA.
Power up again and measure TL074 pin7. This will read about 0.14V AC. Case not, check for shorts, correct 47K resistor values in front of the VCA and 33K feedback resistor between TL074 pin6/7.
TL074 pin1 will measure about 0.42VAC, about 0.1VAC at the junction 10K/20K/kathode 1N4148, same maybe 400Hz frequency as at input, swinging positive. Case not, check for shorts, diode orientation ...
TL074 pin14 at varying ratio settings, double frequency from rectification, will measure at ratio 2:1 about 4.8VAC, swinging between -3.5...-5.5V, at ratio 4:1 0.83VAC, swinging between 0.3V...-1.4V and at ratio 10:1 swinging between 0.3V...-0.2V. This is a DC voltage with rectified audio riding on top. Case not, check lorlin endstop position by (in this order) removing the end stop washer, located below screw and sawtoothwasher, turn the switch full ccw and put the ring back in, set for position 3.
Set ratio back to 2:1. Set Bypass switch for compressor engaged.

Check lorlin endstop for attack (pos.6) and release (pos.5) as previously described.
TL074 pin8 with release in fastest position will measure about -1.2V at slowest attack up to -4.9V at fastest attack.
TL074 pin8 with release in 4th position will measure about -3.4V at slowest attack up to -5.1V at fastest attack.
TL074 pin8 with release in auto position will measure about -2.6V at slowest attack up to -5V at fastest attack.
Set attack and release back to fastest position.

TL072 pin1 with threshold wiper varying DC voltage between full cw (-12V) and full ccw (about +0.3V), measuring between 5.8V and 2.6V.
TL072 pin7 with makeup wiper varying DC voltage between full cw (+12V) and full ccw (0V), measuring between 1.9V and 3.8V.

DBX-202 substitution circuit: NE5534 pin6 measuring between 0.1V and 0.2V with makeup varying from ccw to full cw. Case not, check for shorts, resistor values, ...

Power down, reconnect the GR-meter, remove the 3 wire links and put the audio VCAs and sidechain VCA back in. Watch this parts orientation, differing from the audio VCAs. When using a 4K7 trimmer for meter sensivity adjusting, check wiper for initial setting about centered.

Check resistor values, depending on VCA type and location used.
Sidechain VCA: DBX2150, THAT2180 or THAT2181, check for 3K9 bias current setting resistor between pin5 and -12V, remove 10K resistor between pins 3/5, remove 47 ohm resistor connecting to pin4 when using THAT2180 or THAT2181.
Audio VCAs: THAT2180 or THAT2181, check 5K1 bias current setting resistor between pin5 and -15V, remove 10K resistor between pins 3/5, remove 68 ohm resistor connecting to pin4, jumper 10K resistor between pin4 and 1M resistor position. Remove this 1M resistor and 50K thd-trimmer when using THAT2180. When using THAT2181-Lx, place 120K instead of 1M for 2181-LC, 220K for 2181-LB or 680K for 2181-LA.

Maybe I forgot something or messed up measuring, but this should help you a little to fix it.

Good luck.
-Harpo