GSSL HELP THREAD!!!

[stereokillah]

Harpo , soory but have a question about TraceListen
i'm a old beginner and stay a noobie, how to use it ?

need i use the probe tip to put it on each point under the board with the unit power on?
and which capacitors need i use please?


a precison  when i put the solder iron to make a stuf there is some electricity and the board is not plug to psu.

thanks

 

[tomcat]

With this probe you can hear your audio instead of seeing it on the oscilloscope.

So you connect the probe to your amplifier, the ground 0v croco to gnd on the ssl board and then you can follow the audio signal trough your circuit with the probe tip (like with a dmm/multimeter/oscilloscope). For this you need to have the gssl switched on and you need to connect some audio signal to the input of the gssl.

 

[Harpo]

RCA or TS plug goes in a maybe cheep computer monitor or whatever handy. This amp probably has an input impedance above 10k, so the cap should be 330nF or above. This way you block DC if accidently probing a wrong trace/pin and as this forms a 1st order HPF, the cutoff should be lower than AC mains frequency.
The RCA wire shield is connected to a maybe croco clip for an easy connection to reference voltage of the unit under test, usually 0V. RCA tip connects to one side of the cap. You probe with the other side of this cap without touching the cap leads with your fingers.
Take the croco clip to a 0V connection on the GSSL pcb.
Pull out the audio VCAs and put a temporary wire link to VCAs pin1/8 for THAT218x. If your VCAs are DBX202C, link VCA in with VCA out.
You have already checked that your supply voltages +/-15V and +/-12V are OK.
Power on your GSSL and probe input stages NE5534 pin6. Can you hear this 400Hz or 800Hz in this stage? Yes-replace the probably broken opamp, No-moving on.
Probe current-to-voltage converters NE5532 pin7. Can you hear this 400Hz or 800Hz in this stage? Yes-replace the probably broken opamp, No-moving on.
Probe inverting output stage NE5532 pin1. Can you hear this 400Hz or 800Hz in this stage? Yes-replace the probably broken opamp, No-moving on.
Power down. Pull out the temporary wire links and put the audio VCAs back in. Power on. Switch GSSL to bypass.
Probe current-to-voltage converters NE5532 pin7 again. Can you hear this 400Hz or 800Hz in this stage? Yes-replace the probably broken audio VCA, No-moving on.
Disengage the bypass switch and probe again. Can you hear this 400Hz or 800Hz in this stage? Yes-exchange the maybe broken sidechain VCA with an audio VCA, No-better get a scope.
Good luck.

 

[stereokillah]

thanks for your explaination

i 'll try on dbx out first cause i changed all the 5534 and 32 and nothing change

last thing i have a duty frenquency touch on my voltmeter , can i used it instead, so 'i ll try it tomorow

 

[stereokillah]

ok ike i have'nt amplified monitor at time to do this test,

this is what i think like this noise is amplified with the gain, it come from before the audio vca or from the audio vca
so 5534 are fine, and i tried 4 differents  yesterday  to be sure

if i put out the sidechain vca i still have this problem
if i change the 5532 still have it too

i tried to put out the the 202x and linked in and out on the bard without the vca

don't have the noise

i replace the dbx 202 with wire linked between the in and out of dbx and the noise is back


is it sure it's the audio vca who is bad or it should be something around?

 

[Harpo]

if i put out the sidechain vca i still have this problem

the audio VCAs are not directly connected to the sidechain VCA but to the TL072.

i tried to put out the the 202x and linked in and out on the bard without the vca
don't have the noise
i replace the dbx 202 with wire linked between the in and out of dbx and the noise is back

You should be sure about the type of your audio VCAs.
Is it DBX202 or DBX202x ? (these differ a lot from each other. The gssl schematic shows surrounding parts values for a DBX202c, being different again).
Is the noise back when gssl is switched to bypass ? (Ec forced to 0V, assuming the TL072 being OK, so VCA current-in = VCA current-out)

is it sure it's the audio vca who is bad or it should be something around?

maybe, see previous test.
Double check connection and parts values around the exchanged makeup pot and bypass switch and maybe replace the more unlikely broken TL072.

 

[stereokillah]

i 've already checked the tl072 with another , and the noise is here even whitout control board , bt don't have another dbx202x paire to hear if still have the noise.

it's 202x

whitout or with link wire between in and out of the dbx i have this noise even in bypass mode

i changed the 5534 and capacitors on the dbx and still have noise

the only thing sure is when i put out the vca audio  with le link between in and out vca audio on main board the noise disapear

 

[Bob1991]

Finished the soldering and wiring of my first clone.

So let turn it on:
Audio passes through fine when the GSSL has power. Power LED works, all IC V+/- voltages are correct. Unfortunately none of

the compression controls is doing anything, just the gain make-up potmeter is working (when not bypassed), but

it isn't compressing. Also the GR meter doesn't move (but this is maybe a result of the non-compressing error).

When I touch some pins around the TL074 IC the volume goes down, and also the GR meter shows gain

reduction (because the volume is quieter).  Also, the sidechain THAT is working on a voltage of 12V +/-? (the other 2 THAT's have a stable +-

15V)

Can somebody tell me what's the best way to check it for errors etc, where to measure etc? Caps/diodes are

placed the right way around, and I can't find any shorts on the board.

 

[stereokillah]

check under the board if your solder point are fine and if there is not  bad conatc or something like that, check if there is a signal between the board and control board ( 10 pins) and try another tl074 and tl072

 

[ptron]

also check sidechain VCA isnt backwards (it goes opposite way around than the audio VCA`s)

 

[Bob1991]

Checked the solder points, nothing is shorting, and also I pressed every component to check for cold joints etc.
I was inspecting all resistors, and accidentally found a 100R resistor in the sidechain path where a 100K(!) is needed.
But I was happy a bit too early, this didn't fix my problem.
VCA's are oriented right. Also there is continuity from the main pcb to the control pcb. At last, I replaced the TL074 and 72, but it's still not compressing

 

[stereokillah]

rechecked your bypass switch, if there is resitance in your potentiomenter, and the signal betxeen the three point of your pot and the next point; first to point +, second to  point F, and the last to the resistors 1m1 and 1m2, there is a pdf from Livingnote that could help you http://www.groupdiy.com/index.php?action=;topic=37246.0
and this method http://www.groupdiy.com/index.php?topic=47.msg483540#msg483540

if i put out the sidechain vca i still have this problem

the audio VCAs are not directly connected to the sidechain VCA but to the TL072.

i tried to put out the the 202x and linked in and out on the bard without the vca
don't have the noise
i replace the dbx 202 with wire linked between the in and out of dbx and the noise is back

You should be sure about the type of your audio VCAs.
Is it DBX202 or DBX202x ? (these differ a lot from each other. The gssl schematic shows surrounding parts values for a DBX202c, being different again).
Is the noise back when gssl is switched to bypass ? (Ec forced to 0V, assuming the TL072 being OK, so VCA current-in = VCA current-out)

is it sure it's the audio vca who is bad or it should be something around?

maybe, see previous test.
Double check connection and parts values around the exchanged makeup pot and bypass switch and maybe replace the more unlikely broken TL072.

thanks for your help again Harpo, it was one of two Dbx202x i suposse a 2150 wrong.

 

[React]

hi im building my first GSSL and i have a question about the meterligt.

I have a behringer meter with a light in it and if i want to power the light do i have to build it an own powersupply with its own regulators just to power the light or is there a good spot for taking power off the pcb? I have done a search in the forum and all that is said is "Dont take power, dont take power"

I really want my meterlight to work.

/Thomas

 

[React]

Then another maybe stupid question but i have never buildt a psu before. Im omw to get powerswitch and bypassswitch.

Do i need to break the live AND neutral of the toroid for the powerswitch? or can i just break one of them? cus i dont know what kind of swith a 2-pol or can i use just a single pole?

and then the bypass i want to break the bypass so that makeup gain gets turned off also. "True bypass" here i need a 2 pole DPDT switch if im right? Gyraf is using a lorlin but if i want a switch instead?

maybe is basic questions but i want to do things right from the beginning.

 

[ptron]

Hi!

What is the chance of a mono GSSL build? Does anyone have the schematic/PCB lay outs with just the left channel? Tried doing this myself but quickly got confused and some of the signal paths.

Going to get going with this project pretty soon, I don't know wether to be laughing or crying!

Cheers,
Dave

i dont know if its what u were thinking about but igor`s mixbuzz has the choice of the 2 separate channel controls and link option.. pretty neat thing

 

[ptron]

hi im building my first GSSL and i have a question about the meterligt.

I have a behringer meter with a light in it and if i want to power the light do i have to build it an own powersupply with its own regulators just to power the light or is there a good spot for taking power off the pcb? I have done a search in the forum and all that is said is "Dont take power, dont take power"

I really want my meterlight to work.

/Thomas

is the light LED or what kind? what voltage and current does it take?

 

[React]

hi im building my first GSSL and i have a question about the meterligt.

I have a behringer meter with a light in it and if i want to power the light do i have to build it an own powersupply with its own regulators just to power the light or is there a good spot for taking power off the pcb? I have done a search in the forum and all that is said is "Dont take power, dont take power"

I really want my meterlight to work.

/Thomas

is the light LED or what kind? what voltage and current does it take?

i have been searching the forum and what i understand is that i can get the current for it from the unregulated 15V right of the secondaries of my toroid with a resistor to drop the current from 15V to 12V. (it is a bulb and not an LED that runs on 12V i think according to others on the forum).

So ill have to measure the entire machine during full load and do a bit of calculations to drop the voltage accordingly.

But the ACTUAL current and voltage that the bulb is drawing is a mistery so im pretty much guessing.

 

[ptron]

maybe try some protoboarding with a 9v and then just see what voltage suits it?


EDITED: a bunch out that i already figured out

 

[ptron]

CALIBRATION FOR THE THAT2181LA VCA:


compression ratio adjustment
Replace 100K between pin 8 of TL074 and pin 2 of TL072 with 120K for correct compression ratio behaviour (2:1 / 4:1 / 10:1). I found this value experimentally by measuring the ratio's using the method proposed by "The Lab" member SSLTech, you can look here: http://www.groupdiy.com/index.php?topic=944 if you would like to read the original thread.

which would be the best?? 120k as this explains or the 127k that rev 7 has on the silk pdf?

cheers!

 

[Harpo]

I have a behringer meter with a light in it and if i want to power the light do i have to build it an own powersupply with its own regulators just to power the light or is there a good spot for taking power off the pcb? I have done a search in the forum and all that is said is "Dont take power, dont take power"

Just put a BE46 to my bench supply. Bulb seems to be a 12V/0.6W (and I'm sure you won't like it this bright). I'd probably feed it from regulated -15VDC, maybe 150R 1/2W in series, bulbs other pole to 0V.

Then another maybe stupid question but i have never buildt a psu before. Im omw to get powerswitch and bypassswitch.
Do i need to break the live AND neutral of the toroid for the powerswitch? or can i just break one of them? cus i dont know what kind of swith a 2-pol or can i use just a single pole?

There will be regulations for your whatever AC mains voltage is coming from your wall outlet in whatever galaxy/planet/continent/country you might be to meet the law. This is one of the reasons, a location in your profile might better help others helping you. Switching both life and neutral is the safer bet.

and then the bypass i want to break the bypass so that makeup gain gets turned off also. "True bypass" here i need a 2 pole DPDT switch if im right? Gyraf is using a lorlin but if i want a switch instead?

Dunno about "True bypass" (does something like 'false bypass' exist?). The gyraf version is forcing the audio VCAs in their bypass condition, but signal is still running thru balanced line receivers, VCAs and output driving stages. This requires a DPDT switching function. A lorlin type is just one type of switch to do this. Can be pushbutton, lever, rocker, thumbwheel, relais... If this switch is to display its status, another pole is needed to supply a LED/lightbulb or you could use a simple switch to power a DPDT relais instead. For a stereo balanced 'Hardwire bypass' you want a 8 pole double throw switching function. Relais might come handy for this type of switching.