GSSL HELP THREAD!!!

[mfdu]

those switches are pretty easy, because they simply are on, or off.
is the switch a dual row of three prongs?
the middle of each row simply conects to the outer prongs when switched on. cant go wrong.

but i have.

units not passing audio. chased all +/- 12 and 15 - all there. yet to chase 1kHz through the circuit.

got a couple of points where there is -0.85Vdc on the VCA 5534's , 13.67Vdc and 1.64Vdc on the output 5532's and -0.61Vdc on a pin each of the input 534's
tl074 shows 0.22, -0.15, 0, 0,0, 0, -12.15, 12.10, 0.1, 0, 0.02 , 0, 0, 0
(phew is that all?)

all voltages match each side, the 12V is stable as. but no signal passes.

tried disconecting the control board but no change.

have not tried changed 5532/5534's because they are showing the same volts and stable.

i know next step is chase the signal to where it stops, but any one (gyraf?) got a tip?

chris.

 

[gyraf]

Chris,

Not passing audio at all is a rare symptom.

Make sure that opamps ('32 and '34) are correct types. Make sure that you mounted in and out to the appropiate connectors :razz:

Jakob E.

 

[tree]

Hey Jakob...
Should i be able to check continuity between the "common" post and "selected position" posts of the lorlin attack switch, when it is installed in the circuit?
My tester shows some continuity between the "common" post and some of the "non selected" post positons as well as the selected position.
Normal?

 

[gyraf]

Normal, methinks, when measured in-circuit.

Consult schematic for explanation, or unmount switches to check them. They rarely fail - unless "programmed" wrong (i.e. switch position is "behind" the endstop when this is put in). Always make sure to turn the switches fully ccw (counter-clock-wise) before inserting end-stop.

Jakob E.

 

[tree]

thanks, Jakob.
yes, i can see that the various positions share some things a bit.
guess am being over cautious...

am mounting control board away from front panel (running wires from it to switches) and should have ordered sdr mount switches not pcb variety for this ... pcb variety are a real drag to try to solder wires to.

 

[desol]

Hi.. I don't have a meter yet...
Do i need to have the meter in place for the unit to compress?
I was thinking it wouldn't matter if it was there or not...
Can i put a resistor in place where the meter goes...if i need to...for now?

Thank you...

D.

 

[[silent:arts]]

just leave the meter out, no resistor etc required.

 

[Sender]

Are %1 tollerance reisitors really required for the build or will a 5% do well?

 

[gyraf]

5% resistors works alright..

 

[desol]

thanks for the reply silent arts...

 

[gyraf]

What type of +4 signal? A classic "from taperecorder" +4 FSD/analouge, or one of the modern FSD=20dB over +4 d/a converter?

Many modern d/a converters seems to be set at stupidly-high output levels. Send out a full-scale 200Hz tone and measure on your multimeter. Result should preferably be less than 3-4V AC in order to be comparable with the levels we used to work with in the analouge world..

Jakob E.

 

[EEMO1]

im going insane. i've been troubleshooting my ssl for the last 8 hours or so....


first i had the low signal/distortion thing going on. changed a few resistors, measured voltages etc.

now im in a situation where the unit passes a nice-loud signal WITHOUT the control pcb attached. when i attach the control pcb, no signal or anything.

im open to ideas... please? pretty please?

 

[gyraf]

Naa.. it should pass audio cleanly without the control board attached. There's obviously an error somewhere in your sidechain..

Jakob E.

 

[tree]

Ahhhhhhhhhhhhh!
Finishing my second ssl.
Trying to troubleshoot a problem i've not seen yet in the forum, though i've scoured meta and forum for anything even slightly similar...
PROBLEM:
Compresses identically, beautifuly, on both L and R sides
BUT..... (ouch!)
9 - 10db BOOST on L side!!
R side fine.
Regardless in bypass mode or engaged.

- Checked, rechecked, re rechecked all resistors in output section
- Voltages at both 5532s seem good....
- All cap labels look right...(don't yet know how to measure caps)
- Checked continuity of output harness and connector, patchbay, xlr cables.....

2 DAYS later (':shock:') only thing i've found is a bit of "crosstalk" in the continuity on that one connector, though the crosstalk appears identical on both L and R outs... is that normal?

Is it wrong to assume prob is most likely at output section?

Anyone, please. :roll:

 

[[silent:arts]]

check the 15K* resistor at the input of the audio vcas

 

[tree]

thanks silent.
it checks o.k.
Any other thoughts real welcome.
getting a little bug-eyed from the magnifyin' glass :shock:

 

[[silent:arts]]

the sidechain path is mono, so the problem must be in the audio path - or in the "dbx 2150 to dbx202 emulation" circuit. check and recheck the resistor values there. if you have a scope you can compare the whole path between the left and right channel.

 

[tree]

afraid i don't have a scope.
does it sound loke a resistor issue?
i'd checked all those values prior to installing.
what other sorts of failures might cause a boost like this.
thanks again.
i'd sure be up the creek without the knowldge around here :thumb:

 

[[silent:arts]]

[quote author="tree"]afraid i don't have a scope.[/quote]
try to compare the audio path with a DMM, with a low freq. sinus at both inputs.

does it sound loke a resistor issue?

to me: yes

 

[tree]

sorry, dont follow...

try to compare the audio path with a DMM, with a low freq. sinus at both inputs.

what do you mean by, "low freq sinus at both inputs"?
and how would i compare audio path with my mult meter?
silent,
please have patience with my awful lack of knowlwdge with this stuff