GSSL HELP THREAD!!!

[okze]

i've been testing my gssl and i obtain this:
+12: 12.42
-12: -11.96
+15: 14.89
-15: -14.90
+15: 14.89
-15: -14.91

Are these values ok?

the 5534 into the right VCA is quite HOT. and i have distortion and noise into the both outputs.
the make up gain it's seems to be working how can i test my voltage into the diferents ne55xx and tl 07x what is the correct values?

 

[MeToo2]

i've been testing my gssl and i obtain this:
+12: 12.42
-12: -11.96
+15: 14.89
-15: -14.90
+15: 14.89
-15: -14.91

Are these values ok?

the 5534 into the right VCA is quite HOT. and i have distortion and noise into the both outputs.
the make up gain it's seems to be working how can i test my voltage into the diferents ne55xx and tl 07x what is the correct values?

PSU voltages look fine (depending on where you measured them of course!).
Excessive heat tends to indicate excessive current => normally a short circuit on an output. What current is your board pulling?
Don't know of any 5534 though. Presume you mean 5532. Luckily the output driver of these chips will generally survive a short circuit.

There's several posts earlier in this thread that give example test points and typical values for a mono test tone.

 

[Holiveira]

Thanks for your help,

I put all the resistances in the sidechain. Now I have only the changes in VCAs (2180). and put the 470R

I have 47K in the "L" and "R". I removed them to turn the SSC.

The voltage at pin 7 of the TL074 is the treshold to -10.85 min or max. With audio input, the voltage is -0.5 ...- 1.1 V with max treshold. with the treshold is -7.9 ...- 9.8V min.

I still have the problem. and when I switch the release I hear a click

First you said you removed 47R and 10K resistors. Now you say "I put all the resistances in the sidechain."
Can you please be more precise about which resistors around the That 2180 you removed or fitted?
Or make a photograph. There are 2*47R next to the 2180. One should be removed in your case (pin 4). One should NOT be removed (pin 3)

I would remove the SSC until you get the basic GSSL working, unless you have an oscilloscope and a signal generator.

There are too many variables and possible mistakes on the wiring of the SSC otherwise.

My DC and AC voltages, relative to chassis ground. Note I was intentionally using a voltmeter for AC readings not my oscilloscope, so it may not be reading true RMS.
But I wanted something that you could easily compare.

Test 1: attack 1, ratio 4, release .6, make up mid, SSC off, threshold min (-20), no signal in
Vin +ve phase -150mV DC 0mV AC
Vin -ve phase 350mV DC 1mV AC
SC IN @47K 0.0mV DC 0mV AC
pin 7 TL074 1.1mV DC 0.0mV AC
pin 1 tl072 -2.86VDC 0V AC
GR 0db

Test 2: attack 1, ratio 4, release .6, make up mid, SSC off, threshold min (-20), -10dBm 600R 820Hz signal in
Vin +ve phase -150mV DC 473mV AC
Vin -ve phase 350mV DC 1mV AC
SC IN @47K 0.6mV DC 473mV AC
pin 7 TL074 -5.5mV DC 309mV AC
pin 1 tl072 -4.28VDC 0V AC
GR ±-20 on meter

Test 3: attack 1, ratio 4, release .6, make up mid, SSC off, threshold max (+20), no signal in
Vin +ve phase -150mV DC 0mV AC
Vin -ve phase 350mV DC 1mV AC
SC IN @47K 0.3mV DC 0mV AC
pin 7 TL074 -4.7mV DC 0.0mV AC
pin 1 tl072 +2.85VDC 0V AC
GR 0

Test 4: attack 1, ratio 4, release .6, make up mid, SSC off, threshold max (+20), -10dBm 600R 820Hz signal in
Vin +ve phase -150mV DC 473mV AC
Vin -ve phase 350mV DC 1mV AC
SC IN @47K 0.5mV DC 473mV AC
pin 7 TL074 -5.1mV DC 0.0mV AC
pin 1 tl072 +2.84VDC 0V AC
GR 0

You can see that I do NOT have a high DC offset on pin 7 of the TL074 as I suspected.

HI Metoo2

Thanks!

I have two R47. but raised the pin4 of 2180.
I've solved a problem. my sidechain VCA was not good. I changed and now does not have this problem. but the compressor does not work. threshold, attack, release and ratio. without 47K (potentiometer) compressor acts only at the end of theshold (near -20).

You know what might be?
with or without signal.
PIN1 2180: -1.6 mv

PIn7 TL074: -1.1 mV (at +20 Thresh) and -2.5 mV (Thresh -20)


I found something strange. When the compressor power is on, there is a shunt between the pin8tl074 and earth. I've changed TL074...  It's normal?


Hugo

 

[Enchilada]

WAHOO!!!! I finally got my threshold going. Turns out I had a dud potentiometer. Picked up a new one and now it's working just fine 

Now to get it all in the rack and I'll be laughing!

 

[Enchilada]

Typed too soon...

Dropped my front panel putting it together and now my  GR meter is really sticky, not fluid like it used to me. Seems to be getting stuck until I tap it. To make things more fun, it won't pass audio now either.

Back to the drawing board...

 

[Holiveira]

good,

I've looked many times and did not check the board anomaly. I saw connectivities, values ​​and seem okay.

My ssl only compresses a bit when I have the treshold at -20 (without the pot 47k +).
When I shot the 2 47k (pin 1 vca sidechain) the compressor works in strange ways but it compresses.

Does anyone have a suggestion?

I use the That 2180BL08 with 4 pin up. I changed the 3k9 by 5k1 in VCAs.
I have 10k between pin 3 and pin 5 in the side chain and VCAs.

 

[Harpo]

When I shot the 2 47k (pin 1 vca sidechain) the compressor works in strange ways but it compresses.

You want these 47K resistors in circuit, else you will blow your sidechain VCA. (These VCAs are current-in/current-out devices. VCA-Pin 1 is current in, VCA-pin 8 is current out. No voltage to measure here).

I use the That 2180BL08 with 4 pin up. I changed the 3k9 by 5k1 in VCAs.

VCA-pin5 current source to neg.rail change 3K9 to 5K1 only in the DBX202C substitution circuit. The 3K9 value at the sidechain VCA is correct (this 3K9 connects to the -12V rail).

I have 10k between pin 3 and pin 5 in the side chain and VCAs.

Take these out for THAT218x VCAs. (these 10Ks between pins 3/5 once have been a try to get modulation down for DBX2150/2151 type VCAs).

Double check resistor values, especially the 47ohms at VCA-pin 3 (your R47=0.47ohm probably being a typo), the 100ohms at TL072 pins 1+7 and the opamps feedback resistors.

 

[JAYJAYBEE]

noob question alert ! haha.

ok..ive got the pcb stuffed, the switch board loaded and hooked up, the xlr's are wired. all i need to do now is hook this badboy up to the mains, and sort out my grounding.

which is where you guys come in.

ive got a toroidal transformer  30va  2 x 15v

now the live and neutral go to the iec ( brown and blue ) i know this.

black and orange are 0v
red and yellow are 15v.

im having problems figuring out which pin to put them in ( there is only 3 ).

This is probably the longest build in history as i started building this 7 years ago, so please help as i really need to finish this.

cheers

 

[gyraf]

black and orange are 0v
red and yellow are 15v.

Not enough info - we'll need to know what are the starts and finishes of the windings. What exactly does it say on the transformer label / the specs sheet?

Jakob E.

 

[JAYJAYBEE]

black and orange are 0v
red and yellow are 15v.

Not enough info - we'll need to know what are the starts and finishes of the windings. What exactly does it say on the transformer label / the specs sheet?

ok. heres all the info i could find

TRANSFORMER, 30VA, 2 X 15V
Power Rating: 30VA
Secondary Voltages: 2 x 15V
Secondary Current Nom: 1A
AC Power: 30VA
Approval Bodies: UL Recognised
Bolt Length: 40mm
Bolt Size Max: M5
Current Rating: 1A
External Diameter: 73mm
External Length / Height: 31mm
Mounting Type: Chassis
Output Voltage: 15V
Regulation: 14%
Secondary Power: 15VA
Single Primary Voltage: 230V
Temperature Rise: 42°C
Transformer Type: Toroidal
Weight: 0.5kg

and ive attatched the windings diagram which is on the side of the toroid

Jakob E.

 

[Harpo]

and ive attatched the windings diagram which is on the side of the toroid

Join red and orange wires for the center tap and take this connection to the center of these three holes for AC-hookup on pcb. The black wire goes to one of the outer pcb holes, the remaining yellow wire goes to the remaining pcb hole. Order of outer hole connection doesn't matter for AC.

 

[JAYJAYBEE]

and ive attatched the windings diagram which is on the side of the toroid

Join red and orange wires for the center tap and take this connection to the center of these three holes for AC-hookup on pcb. The black wire goes to one of the outer pcb holes, the remaining yellow wire goes to the remaining pcb hole. Order of outer hole connection doesn't matter for AC.

thanks man.

 

[Looksharp]

hi,
I got the same doubt as Jayjaybee for my trafo..could you please help me too?
here are the info:
Toroidal transformer,30VA 2x15V o/p ,230v
...and the diagramas file attached
thanks

 

[Harpo]

red | black+yellow | orange, or same as my previous answer.
You want this (same voltage or turns ratio per secondary winding) dual secondary transformer behave like a center tapped transformer. This is done by joining both secondary windings in series, so an in-phase wire (indicated by a dot) from the 1st secondary and an out-of-phase wire from the 2nd secondary is at the combined windings ends. The center tap is the junction of the remaining two secondary wires (in-phase+out-of-phase) from these combined windings.

 

[Looksharp]

Thanks Harpo!

 

[wthrelfall]

Hi folks, I've just started building my first GSSL compressor, and actually my first electronics project, although I have a bit of experience with a soldering iron and lots of experience taking things apart 
Anyway, over the last couple of weeks I've been reading through what seems like thousands of pages relating to the GSSL, and my brain and eyes are beginning to shut down!  I'm loving the fact that all this info is being posted by good people like yourselves, but I'm hating reading thread after thread after sub-thread after sub-thread in order to find out why/if/when I need to change the value of a resistor... Only to find an 8 year old answer which has now been super-ceded by a different or better solution... back to the 'search' UHHH  :-\
So it got me thinking: Maybe someone has some time and inclination to start a brand new thread aimed at GSSL/DIY audio electronics 'newbies', which gives an updated for 2012 rundown of the 'Gold Standard' GSSL compressor.  That is, a description and photo of each 'mod', pro's and con's, difficulty of adaptability to the 'base' design etc.  Plus it would be nice to have a definitive answer to those resistor value questions..  just for example, this page describing what resistors to remove when using the THAT 2180 - http://diy.fischerworks.com/gssl_vca.shtml - it's great work but it leaves some info out - 100K ?, 47K ? !!!(i'm not ASKING this Q on this forum, just an example of the kind of info which to me as a newbie is VERY difficult to get to grips with). 
Now, to those people who are going to reply with, 'just read through the threads' or 'just do a search', I'd like to reiterate that I'm not incapable of doing that, and as I said earlier I already read so much I'm going cross eyed (literally).  Just looking for a refreshed and condensed thread which makes it easier for newbies to have a clear vision of what and how they can build this beast.
Once again, thanks to Gyraf Audio and all the other amazing contributors who are making this possible for guys like me and you.

 

[Looksharp]

hi again,
I 'm soldering the components on the pcb, purchased from Chef at audiokitchen...
I've noticed that the list of components and the pcb layout on the pdf manual  asks for two 27k resistor ,the ones at the left of the two VCA, while in the Chef' Pcb there are stamped ,in the same place, two 15k resistors....which do I have to use?
and again,in the list and depicted on top of the pcb in the pdf  ,at the right of the TL074, there is a 127k resistor while in the Chef' PCB there is a 100K...which one do I have to use?
thanks guys...
L

 

[frazzman]

Chef's PCB is an old revision... the pcb has been revised since then, most notably with the changes you've identified, i've used chef's pcbs a number of times as well and noticed this.

Change the two 15K resistors to 27K

And the 100K to 127K improves the ratios, this value can be messed with a bit. I used a 100k & 20k in series here, but just do what works. You can find 127K resistors, but if you can just link up a 27k and 100k....

hi again,
I 'm soldering the components on the pcb, purchased from Chef at audiokitchen...
I've noticed that the list of components and the pcb layout on the pdf manual  asks for two 27k resistor ,the ones at the left of the two VCA, while in the Chef' Pcb there are stamped ,in the same place, two 15k resistors....which do I have to use?
and again,in the list and depicted on top of the pcb in the pdf  ,at the right of the TL074, there is a 127k resistor while in the Chef' PCB there is a 100K...which one do I have to use?
thanks guys...
L

 

[Looksharp]

thank you very much!
i imagined that the pcb is  a first run from the beginning of this wonderfull diy project and there is no need at the moment to make this kind of minor changes (resistors values) to the silkscreen...
also noticed that  the BOM list got a little error: it ask for 9 of 100pF ceramic capacitors while in the pcb there are 10 .. 
thanks again...

 

[wthrelfall]

I have a number of these EAO switches, does anyone know if they are suitable for use on the GSSL?
http://products.eao.com/index.php?IdTreeGroup=124&IdProduct=48307
thanks.