GSSL HELP THREAD!!!

[[silent:arts]]

connect a signal generator, synthesizer, test cd - whatever - to both inputs. you need an input signal to measure / compare. measure the voltage at pin 6 of the NE5534s at the inputs, compare. measure the voltage at pin 1 of the NE5532s at the outputs, compare. measure the voltage at pin 7 of the NE5532s at the outputs, compare.

 

[tree]

hey silent -
so i sent a 1k tone to a couple of console rails @ 0db
then to both sides of the Gssl via inserts...

Right side of Gssl returns at unity (on consoles master section meter)
Left side at +9db

the db dif stays the same whether comp is engaged or in bypass

mult meter shows both 5534s PIN 6 = 0
both 5532s PIN 1 = 0
5532 PIN 7s = 14.85

adjusting thresh or gain makes no dif to the readings.

:?
should dc at pin (out) of 5534s = pin 1&7 (outs) of 5532s???
i hope i haven't missed the point entirely
thanks again, btw.

 

[EEMO1]

pulled everything from the sidechain section, still no go. the audio is low, plus a little distorted. the controls don't work.

yesterday the channel ne5534's got very hot, maybe i fried them...

 

[[silent:arts]]

Do a small test: disconnect the "-" (pin 3) at both outputs. all fine now ?
if yes, check all the resistors around the second opamp of the NE5532.

 

[EEMO1]

nope, that one didn't have much effect.


umm... does someone have all the correct ic voltages listed?


-e

 

[[silent:arts]]

[quote author="EEMO1"]nope, that one didn't have much effect.[/quote]
sorry, that one was for tree

 

[tree]

thanks silent -

2nd 5532 meaning to the right if facing output section?

can do this afternoon and report back.
really apreciate the quick responses....

 

[tree]

silent...

okay, lifted pin 3 at connector, fed both sides tone as above.

STILL 9db hotter on left side. :?

ne5534 PIN 6 = 0
ne5532 PIN 1 = 0
PIN 7 = 0

does this indicate anything to you????
afraid i'm a little lost here.

any thoughts at all.

checked resistor values with meter as i was originally installing and a 2nd and 3rd time time since - tho only by color code, not meter...

 

[gyraf]

tree,

Check (compare) signal levels directly after input amps, e.g. right before the sidechain summing resistors. This shows wether input circuits are alright.

If they are, you have a problem in either VCA's or output stage.

The vca's are kinda integrated into the first output driver stage (the one driving +output) so they are hard to troubleshoot individually. Providing same levels from input stages, compare levels at +out's.

Check (compare) DC voltage at the VCA's control pins.

Check resistor values around these circuits.

Jakob E.

 

[EEMO1]

ok, i wrote down my voltages.

my rails are +14.88, -15.00, +12,07, -12,00.

ics:

input ne5534's pin 4 -15.00 and pin 7 -14.88 on both input ics.

vca section, both ne5534's:

pin 2 -14,78
pin 4 -15,00
pin 6 -14,80
pin 7 14,89

left vca pin3 -14,80, pin5 -14.94, pin7 14,88, pin8 0,07
right vca the same but pin8 was 0.02

sidechain section

tl072 pin8 12,02

tl074 pin4 was 12,02

sidechain vca pin7 was 12,02 too.

output ics:

right pin 1 0,03, pin2 0,03, pin4 -15,00, pin6 0,02, pin7 0,02, pin8 14,89

left pin 1 0,08, pin2 0,08 pin4 -15,00, pin6 0,08, pin7 0,08, pin8 14,89.


any help anyone? im gettig a bit frustrated here...

-eero

 

[gyraf]

eemo,

Input opamp specs looks somewhat wrong. Check that it actually IS 5534's..? Check dc voltages at input and output pins (2,3,6) And check for shorts to minus supply lines in that area..

Jakob E.

 

[tree]

Jakob,

Check (compare) signal levels directly after input amps, e.g. right before the sidechain summing resistors. This shows wether input circuits are alright.

... not sure, was yer sage advice meant for my troubleshooting issue or EEM01???
in my case, since both sides compress equally - ratio/attack/release-wise, i was assuming input area must be okay.

wrong though?

...my prob being +9 extra db on left side output.

thanks for anything. :?

 

[gyraf]

that last one was for EEMO1, the one before that for you.. edited..

 

[tree]

thanks for clarifying, jakob.

Check (compare) signal levels directly after input amps, e.g. right before the sidechain summing resistors. This shows wether input circuits are alright.

apologies, but i don' have a scope, only small mm...do i need scope for checkin signal here?
it's not dc i'm looking for, right?
And...
the fact that both sides independently compress identical, doesn't rule out possible input section prob, right?

 

[gyraf]

Tree,

You could measure AC at the two resistors. Compression would always be tracking, as we have a single sidechain.

 

[tree]

thanks jakob;

does this look right to you?

on the 22ks (off PIN 6 of ne5534) L = -.60, R = -.62
on the 47ks (right before pin 1 of S.C. VCA) both L & R show -.17.
on the 15ks (at top of VCA 2 circuits) i get -.60, -.62

relatively normal?
:green:

 

[tree]

correction....
those 22ks, not sure which ones L or R :green: :green: :green:

 

[tree]

Check (compare) DC voltage at the VCA's control pins.

Check resistor values around these circuits.

okay, went back at it....

only dif between L & R vcas that i can find seems to be on PIN 3 (Ec-).
L = -.05 and R = 0 :?
is dif insignificant at all?

swapped vcas, dif remained....and unit still +9db hotter on L side.
swapped ne5534s while there too...no change.

pulled and measured all resistors in L vca circuit.... all check right.

so - does this leads me back to output section?

should i just pull it all out and start over??? :roll:
but sooo close...


anyone?

 

[gyraf]

Tree,

Your input circuit looks fine from here (If the said voltages are AC! - always tell that explicitly for reference..)

Try removing the two sidechain VCA's, and connect the input to the output on the - now empty - socket with a small piece of wire. That would be pin1 to pin8 - the two outer pins.

This rules out the VCA gains - now check your AC levels at the output - measure AC level referred to ground at both + and - out individually. All four outputs should be close to the same level.

If levels are still different, then check component values, shorts, and breaks at the output stages - that would now be the area where you have the problem.

If levels are now the same, then the small DC voltage at the control pin of one of the VCA's is the troublemaker. Check that area (including the related 5534) for shorts and component values

Jakob E.

 

[EEMO1]

[quote author="gyraf"]eemo,

Input opamp specs looks somewhat wrong. Check that it actually IS 5534's..?
Jakob E.[/quote]

umm, what do you mean by check that it actually IS ne5534's?

-eemo