GSSL HELP THREAD!!!

[hotbaby]

i use pcb connectors. many others too. it has several pros.
banzaieffects.com/PCB-Connector-25-4G-pr-26274.html
You can combine 2x 5pin for 10pin or so. That is what i did in my case.
you should only use solid strand for jumpers,bridges or short and naked connections [edit: and your telephone  ].
best
aa

 

[damien]

Oh yes, you're right I bought Molex connector too.
But I wanted to know more about the wires their gauge number of strand and material.

 

[hotbaby]

you should contact sommercable.com. they have a hugh knowledge about the technical pros and cons of cables.
I just bought there the most studio cable stuff and the quality is awesome especially the shielded cables...
for diying i just use twisted 0,37mm cables.... what i have lying around. You can use the inner one of microphone cables too if you have some left over...
when i started diying i used very often shielded cables but i become lazy and just use the pcb connector one... can´t hear / measure differences. The most important part is wiring up the machine correct (no high voltages near to audio cables,...). By the way, all gear i have opened used just normal 0,25mm-0,40mm cables...
the best audio quality cables you can get are the strands twisted ones... but as we talk about less than 100cm wires the difference wound be hearable. most twisted strand cables are found in high quality AES multicore cables or digital tranfer cables that are very sensible for minimal signal losses. I have used it one time for a analog project but they are to expensive as there is no audible difference at all...

 

[zayance]

Hi everybody!
I'm getting back to electronics, i got myself addicted to this again a couple of months ago, i have good soldering skills in PCB, since i've made some preamp kits that worked right away with no bad soldering issues or whatever, i'm very carefull of that during the building process,  and this GSSL  project helps more understand what are in my books with hands on experience, even if i'm a little far from the Opamp designs and all, but this project gives me a good knowledge before getting there, so thanks for helping guys and thanks to this forum it's really a great place to go and find infos on how to do...

So I've finished stuffing and wiring a GSSL with a Supersidechain board, and before testing audio, i wanted to make sure all voltages feeding all the IC's were ok and if signal gets IN and OUt. I've read posts here and made some of the testings that have to be done in order to check if signal passes all the IC's IN and OUT pins. And here is my results and some of the issues i've found:

All the voltages for the +15/-15 and +12/-12 are correct i've checked on all the places refered on the PCB
I stuffed the IC's when i check the VCC pins on the sockets but mabe i had to wait???
And don't remember if there was signal going in when i made those tests, it's been a couple days now, didn't had much time, anyway:

Voltages on 5534 at Input:

pin 1 about 12.3V
pin 2 less than 50mv (about 5 to 7mv)
pin 3 less than 50mv (about 5 to 7mv)
pin 4 -15V on both
pin 5 618 mV on both
pin 6 0.1mV on both
pin 7 14.77V on both
pin 8 12.3V on both

I believe 5534's are ok.

Now  the 5532 at the Output

Pin 1 Left channel: 0.6mV
Pin 1 Right channel 13.74V  ???

Pin 3 0V on all channels
pin 4 15.07V on all channels

pin 5 left Channel: 0V
pin 5 Right Channel: 70mV  ???

pin 6 Left Channel: -0.1mV
pin 6 Right Channel: 0.7V  ???

pin 7 Left Cannel: 1.7mV
pin 7 Right Channel: -13.7V  ???

pin 8 14.77V on all channels

Is the right channel the symptomes of a fried IC??, or am i having issues somewhere along the path and if yes where do you think i have to look at?? Hotbbay seem to have the same problems and i've checked from what Kambo said about this kind of problem, but everything seems to be ok, no bended pins, no solder bridge anywhere on the PCB, resistors are ok around 5532, maybe a bad VCA???

Voltages on the 5534 in the VCA's circuit:

pin 1 12.17V both
pin 2 -0.1mV both
pin 3 -0.1mV both
pin 4 -15.07V both
pin 5 12.16V both
pin 6 14.77 V both
pin 7 left channel -0V
pin 7 Right channel 0V
pin 8 -0.616 V both

I think they are ok?

VCA voltages, i'm using 2180LA ( trimmers out from the PCB):

pin 1 -15.3mV VCA1  ??? I think there is a prob here, it's not a voltage input but a current from what i've read, but maybe this is normal because i had Signal IN maybe?
pin 1 0.5mV on VCA 2

pin 2 -0V VCA1
pin 2  0V VCA2

pin 3 -0V VCA1
pin 3  0V VCA2

pin 4 -0V VCA1
pin 4  0V VCA2

pin 5 -2.79V on both

pin 6 -0V VCA1
pin 6  0V VCA2

pin 7 +14.77V on both

pin 8  0.695V VCA1  i think that means i've actually made those test with signal in
pin 8  -0.1mV VCA2

TL072 (Pin 1 is varying with the Threshold)


pin 1 from 113mV THR at min to -3.11V at max
pin 2 0.7mV
pin 3 0V
pin 4 -11.78V
pin 5 0V
pin 6 -1.2mV
pin 7 -2.9mV
pin 8 12.23V

TL074 (pin 1 / 7 and 14 are varying with Threshold)

pin 1 from -105mV THR at min to -33mV THR at max
pin 2 0.3mV
pin 3 -0V
pin 4 12.29 V
pin 5 -0V
pin 6 1.4mV
pin 7 from 2mV min to 32mv max
pin 8 0.5mV
pin 9 0.4mV
pin 10 0.9mV
pin 11 -11.8V
pin 12 0V
pin 13 1.6mV
pin 14 from 212mV min to -18.5mV max

Now when i tried the audio signal tests, i've fed the input with a 1Khz sine wave and checked at the IC's if the signal is going thru ( referring to a reply post from RemcoV)

Checked pin 6 of the 5534 and the signal goes thru no prob

Checked pin 1 and 7 of the 5532 and the left side is ok but the right side is not, because of the large DC that gets in pin 1 and 7

At TL074 i checked pin7 which is variable with Threshold and everything is ok
"At pin 14 there must be a rectified DC voltage following input signal level", i believe that's what i have it looks like shark teeth, growing with the THR pot..... ???


"At pin 8 there should be a replica of that signal timed with attack and release" and i don't have that at all.

"At TL072 pin 2 you find the signal again, but added with variable DC voltage from the makeup gain pot" i don't have that...

"At TL072 pin 7 you find the signal from 074 pin 8 again" and i don't have that.

So from what i see is that i loose the signal coming out pin 8 TL074, and why i don't know, bad IC???? And of course Vu doesn't work because of that....

I've checked the resistors around the 5532, the values are correct, and maybe i've burned the 5532??, and the others also but i'm not sure, right now i'm kind of lost in all the tests and i don't know what i really have to do, change IC??? VCA??? Don't want to burn them again if that was the first problem.
And i haven't checked how is the audio still, because i believe it will have problems because of all of that, so just want to make everything ok before that.

Thank you very much for your help and i hope i'm not bothering again with same issues of others, i couldn' read all the 171 pages, some of the beginning and some of the end which actually help a little bit, but got me kind of confused also.
This is a big post, i preferred to wait until i have it all, and these values make things more clear i believe, so thanks again for your time.

 

[kambo]

if you think the resistors are fine around 5532, try swapping  them... see if the working channel swaps too

kam

 

[zayance]

Thanks for your help kambo, i'll try that when i'm back on the desk, but what do you think about the voltages they seem to be correct besides the 5532 that has a prob?
And what about the output of TL074 why is there nothing? I have the supersidechain board wired to the main PCB, and signal is going thru on that one also no prob... Thanks a lot

 

[kambo]

actually, dont swap them around, you might burn them it again... take the IC from its socket and measure the V on every pin...


EDIT : i thought you might swap them before trouble shoot the dcV on IC socket first...

EDIT : 074 is for control only, check with schematic.....
actual audio in/out circuit works without sidechain VCA, tl074 and tl072, and control pcb

so, you can check audio in/out without those ICs

 

[zayance]

Thanks, i'll try that...

 

[zayance]

By the way Kambo when i checked if audio was passing, like i said it was passing on the 5532 but the VU wasn't working no movement at all, i'm using a behringer with LED , is this normal?, but LED is working... Thanks again Kambo...

 

[kambo]

can you hear if the compression is working ?

crack up the threshold, you should get some nasty sound
if there is no comp, no movement is normal... meter shows gain reduction only....

 

[zayance]

Ah yes of course that was stupid question, i'll check with threshold but i think i did that but will check twice, and i'll plug for audio but when 5532 prob is solved, thanks again...

 

[zayance]

Ok Kambo, these are the voltages i get on socket pins with the 5532 out in the right channel were i found a prob:

pin 1 0.755V
pin 2 0.750V
pin 3 0V
pin 4 -15V
pin 5 -0V
pin 6 0.755V
pin 7 0.755V
pin 8 +14.81V

What do you think? Thanks agin for your help Kambo.

 

[zayance]

Oh and by the way when i said before i checked that with the threshold it was with the scope and the sine wave, and i remember seeing some weird things when cranked that's why i said to you i tryied that, but haven't tried audio yet as i said.

 

[zayance]

Are these normal voltage values for the 5532? I've done the test with no signal and with VCA in, pin 1/2/6/7 were at 0.7V and when i took the VCA out they were at 0.5V, and that is for the right channel. Because the left channel that works has pin 1/2/6/7 having very tiny mV, so i believe there is something wrong in the way to the right channel, could it be a leakage in a cap or something else? Thanks

 

[kambo]

0.755V ??? its near 1V
do you mean 0.0755, as i read 0.052 V on mine... with no signal on the input...

compare with other channel... if they are more_less the same, then its safe swap IC's and give it a try...

once its all fine,
VU: read V  on VU connection points on your control board, with some audible gain reduction... check your VU separately if its not faulty or not... your cable connections might have some cold soldering, or wrong connection...

 

[zayance]

Yes really 0.755V, weird, the left channel has about the same values as yours, a couple of mV, don't know where to look at, it's bizarre, solder joints are ok, and components are pretty close together, because of the layout that is not that good you know, but i don't see why this voltage at those pins...

 

[kambo]

you must have a bad connection or soldering or a wrong resistor value etc.,,

try start from audio VCA's output, and carry on until you find different V value then check components there....
or
start tracing backwards, and mark where you meet the same V with the working channel... then check components around there...

dont swap anything yet

EDIT : since you have a scope, its easier to trace the bad point/points

 

[kambo]

ok, i think your 5534 (next/across from your THAT 2180 chips ) in audio VCA is wrong way around, or burnt on your channel...
while the power is off when i took my 5534 out,  (EDIT : power back on again) i have similar readings to your readings..


cross check pin V on 5534 with your working channel, ( IC' off ) ...
if it seems fine, then swap them... then check your 5532 output pins again,
see if its better now... if its, then you r sorted

 

[zayance]

Well the Voltages at the 5534 on VCA circuit are the same as before when swapped, and it's weird because i have sended a post with a link but it doesn't seem to appear, maybe my link was not official, well i have some close up pictures of the output circuit front and rear for you to see, solder parts.... if this can help, it's in my picasa album, tell me if you have that, and maybe it will not help but still, and i can do some more closeups??? Thank you very much for your time Kambo you rock!

http://picasaweb.google.fr/zayance/GSSL?feat=directlink

 

[zayance]

Oh and on the last post that seem to be lost i was saying to you that when i took the motherboard out to take close pictures, well i put the MB back and retested the 55332afor pin voltages and now i had 0.326mV  ??? Weird, maybe connection, but XLR are ok  connection ( + for 2 and - for 3 1 for ground, on molex they are well connected no prob with that and as you can see on the picture of the open rack, the XLR grounds are connected together to the star ground were you have the IEC ground, just for info)