SSL help needed. Please.

Need some help please guiding me in the right direction.

Problem:
I wired and fired up 2 of those nice SSL.
One board came out a bit dirty due to a crappy solder tip and i forgot to wipe off the photostuff with aceton.
The other board looks pretty good. Everything is shiny, got a brandnew tip, measured every resistor before it´s soldered (except of the MegaOhms cause my DMM is too small (!) - uh, maybe there´s the fault?! )
I have all the right voltages +/- 15 +/- 12, the XLR´s are grounded, the unit passes audio. dbx in right direction (used verbos´). I have bridged the Makeup/Bypass conn. on the control board with a jumper because i still miss the switches. (both bypass joints and the com/on joints) Meter works like it should, threshold drives the meter different, meter follows signal.
BUT
Makeup doesn´t work, there is no audible compression and in my opinion, the voltage regulators getting too hot. It takes maybe one or two minutes, then u can´t touch them much longer than a few seconds. Maybe this is normal, i used 2x18V torroid? So i switch it off after 1 minute and don´t have much time for measurements..
Voltages vary on 074 pin 7, somewhere between +0,15 and -1,9 Volts, i measured 072 pin 8 i think, but there are not the voltages inverted like Jakob suggested.
Both channels passes audio clean and without distortion. But theres no audible difference when compression is ON

The same behavior with the other control board.
Today i spend a few hours for tracing the board for solderblobs, shorts, cold joints eg. Nothing. Everything seems fine. BUT NO COMPRESSION

Someone mentioned that he put a 3M9 instead of an 3K9 in control board. Replacing it with the RIGHT 3K9 so it works. But the layout PDF says 3M9.
Which one is the correct? And how hot could the regulators get??

Any hints? Thanks in advance

toby

2x18V will be considerably more voltage than you needed, and the regulators will dissipate any extra voltage as heat.

Mine's running cool enough without heatsinks with a 2x15V toroid. I'd suggest you get a new trafo or heatsink those regulators. If you can't keep your finger on it, it's too hot!

Yes, thanks. I think i will desolder them and cool them via the case. But Jakob suggested either 15 or 18 V and my local store just have the 18V.
In the meantime i found one very very very tiny scratch on the pcb, cutting one trace of an VCA section - but this doesn´t affect the Problem.
Audio on both channels but NO AUDIBLE DIFFERENCE when comp ON..
toby

be careful mounting those regulators, I'm not positive but I think the tab of the case is connected to something other than ground, ie either Vin or Vreg.

If that's the case, when you mount them on the case you'll short them together, which is NOT going to make your trafo very happy

One thing I noted that is very easy to get confused about is the wiring of the bypass switch.

If you put the bypass on, do you start to get metering? Is the metering doing anything as of yet?

Regards

ju

Use a small heatsink if the regulators gets too hot. But remember to mount it isolated, as there's voltage difference between the two regulator's heat-fins.

If you don't have any compression, and makeup dosen't do any difference, then trace the DC signal from the TL072 Pin7 (CV to VCA'S - the two halves of the opamp - pin numbers - are switched on the schematic) thru' to the vca's.

TL072 Pin7 shall vary with compression (following the meter) and with makeup gain.

Look at the schematic, and follow the signal.

Jakob E.

Thanks for your replies.
Sure, can´t mount them on case - different voltages - i forgot

And yes, the bypass works correct. I´ve bridged the joints. when i disconnect them, the meter stops reading...

@Jakob - i´ll try to trace pin 7 signal to vca. It varies with the threshold and - if i remeber right- even with the makeup. I´ll try it today...

Many thanks
:sam:

Hi toby,

Have you read through the ssl-clone meta?

It seems that we've had the exact same problem before:

http://www.groupdiy.com/index.php?topic=798

Jakob E.

Hi Jakob,

yes i read this. i always search the forum and read a lot of threads and posts. i´ve printed it out and read this part several times.
but it seems that this is not my problem.
chris mentioned a wrong res. 3K9 instead of 3M9. Mine is 3M9 on both controls and this is right i think.

I checked all my resistors before i soldered them in - right out of the package - everything should be ok. Ole Hendriks Problem at the end was a 100 Ohm instead of an 100kOhm, so i think this couldn´t be my problem...but never say never!
I will recheck every issue today or maybe tomorrow because I have a turkish singer in studio today :razz:

Thanks a lot so far, this is really a great place, and nowbody seem to get tired answering sooo many questions of newbies like me

regards
toby

success! :razz:
I traced the DC out of pin 7 TLO72 and it comes out that one solderjoin - which looks pretty fine and shiny- of the bridge right beneath the right VCA was dead. Maybe due to the tape with resistors are fixed in large quantities, cause i allways used solderlegs for bridging...

Now this one unit works fine, despite the VRegs needs some cooling. I measured 19,6 V out of my PWR Xformer :?
But overall a great sounding unit. Thanks Jakob :thumb:

That's good news, Toby!

Now go and compress the s*** out of your tracks.. :razz:

Jakob E.