GSSL HELP THREAD!!!

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BackHand,

I had a couple similar problems. Here's some ideas that might help:

For the 5db down in one channel, check around your 5532's on the inputs and outputs. Make sure you don't have a solder bridge between pins 1 and 2, or 2 and 3. If you do, it will be down about five dB in one channel.

I'm not sure why your compressor controls wouldn't work. When you take the unit out of bypass, does the meter slam all the way to the top of the scale, or does it just do nothing. When you take it out of bypass, does any sound come out, or does it just sound the same as when it's bypassed? Are you positive that you've got the bypass switch wired up correctly? Sometimes it helps to remove the bypass switch and just hard wire it into compression mode, to make sure that it's not the switch. Is it possible that there would be a solder bridge between the meter input and one of the pins that connect the controls board to the main pcb?

In the end what helped me troubleshoot my problem the best was to take a look at the pcb etch .pdf file, and double check to make sure that you didn't accidentally bridge any points that weren't intended to be bridged. That's how I found the little piece of solder on my 5532 that was causing it to be down about 5db in one channel. Sometimes it's hard to tell on these little pcbs if something should be bridged, or should not. It's a really easy thing to miss.

Just keep searching, eventually you'll find the problems if you're persistent.

Jay
 
Backhand,

I just read on one of TMBG's posts that his meter wasn't working because he had it wired backwards. That's another possibility!
 
[quote author="BackHand"]
I just built a SSL compressor using the Gyraf Audio kitt.
I hooked it up for the first time now and got some problems :sad:
None of the compressor controlls (attack, relase, threshold and ratio) makes any diffirance? And the meter is dead.. :sad:
But is recieves audio signals and sends them out, the makeup gain and the Bypass switch is the only things thats working. One more thing, theres is about 5 dB louder signal in the right output than the left?
What could disconnect the meter and all the compressor controlls (the bypass seems to be working since the make up gain disconnects when a swich on bypass) ?!
Totally lost... :sad: :?: :!:[/quote]

I'm in the exact same boat. Identical problems. Anyone know what we're doing wrong here?
 
bypass wired correctly?

There's two bypasses, a SPST makeup gain defeat, and a SPDT compressor bypass.

I have mine wired to a 4PDT pushbutton latching switch, with an LED on one pole. Works great :)
 
Bypass is a simple 2 pole switch and works fine. defeats make-up and lets dry signal through. When not engaged, make-up works, but that's all that does. I can't see any pins crossed on the 5532's, but when I press on the 5532 for the left output, or on the .1uF cap next to it, I get a horrible crackling.
 
tmbg - I found it. You were right. Stupid me had the bypass switch hooked up to the make-up defeat, but the compressor in/out connects on the PCB were open. Hooked up the switch in there and bingo! Everything's dandy in candyland.

BackHand - If you still haven't fixed yours yet, check that out and see if that's the problem. It's the 3 PCB solder points on the right side of the control board labeled "com", "on" and "off".
 
No takers on my AC voltage issue? I checked and rechecked my soldering, components, and wiring. I did forward and reverse diode tests on all the diodes in my sidechain and they all seem OK and are installed with the correct polarity.

Can someone with a succesful GSSL build run a sine wave through it and see if they get any AC at points "B", "C", or "D" on the schematic? I'm still not sure if this is my problem, but it makes sense to me that if the CV input of the audio VCA's are seeing AC, then they would cause flutter, which might sound like distortion. Sort of like pulling a fader up and down at 60 cycles/second.

BTW, I'm using the DBX c1252h2 VCA's.

Thanks,
Chris
 
Chris,

AC measurements on the sidechain voltages are not really telling us anything - they're entirely dependent on sidechain timing setting and input signal frequency

And off course you'll get distortion when there's a relatively large AC component on your SC voltage - that happens on all compressors, and is a result of too fast a timing applied on too low-frequent a signal source.

This is a compromise needed for all compression.

Jakob E.
 
Thanks Jakob. I'm glad I didn't get caught up on the AC then. The symptoms you described are exactly my problem, with more distortion at low frequencies and short attack and release. I still must have done something wrong though, because even though there is less, there is still noticible distortion at long attack/release for full range material (like a mix). I compared the sound quality side by side to my friend's Smart C2 and there was no distortion present in the C2 at comparable settings. In short, I wouldn't use my GSSL on a mix yet. I guess I will actually try to measure my time constants in my side chain to see what is happening. Maybe I can convince my friend to loan me his C2 as a reference.

Do you think this distortion difference between my GSSL and the C2 might have anything to do with the DBX c1252h2 VCA's I used?

BTW, this is my third DIY project, after a G7 and a G9 (which both went smoothly). Despite my lack of success on the GSSL, I am learning more on this project. I appreciate all the feedback from everyone.
 
[quote author="Emperor-TK"]
Do you think this distortion difference between my GSSL and the C2 might have anything to do with the DBX c1252h2 VCA's I used?
[/quote]

No. You clearly have a sidechain problem, if working-distortion is audibly annoying at decent settings.

It would be best to trace the sidechain signal with a scope.

- Check your full-wave sidechain rectifier and threshold diode for wrong-oriented diodes.

- Check value and polarity of your timing caps (the 0.47uF tantalums)

- Check values of sidechain timing resistors.

Jakob E.
 
hey,

i've stuffed my boards. now's the time to wire things up. im not sure how to wire the rotary on/off switch (4x3, programmed to 2) im not sure about this one.

any help is appreciated,

eero
 
EEM01:

I'm not sure if you posted this before or after our PMs... were you able to get the ON/OFF switch working?

Just as a side:
I think I'm going to label the BYPASS switch as the ROCK knob when I get my engraving done. I put my GSSL on my main mix buss the other day just to see what it did, and compressed at 2:1, maybe 1-3dB with auto release and middle attack position. I kept switching the BYPASS back and forth and thinking to myself... this mix rocks, this mix doesn't rock, this mix rocks, this mix doesn't rock. The more and more I use this comp the more I like it (at least on certain things, of course)... I'm not a fan on vocals.
 
hey,

yeah i got the pms. thanks.

the on/off switch worked like a charm. first try and everything. now i just have to wait for the 2u rack and finish the unit. can't wait to get it finished. i got songs waiting...
 
Yea... I really need to get it finished. I'm distracted right now because I'm sourcing parts to build a pair of API 312s. I'm sure I could finalize the .fpd in a couple hours. I'll get it done soon.
 
Hello everybody! I finish my first SSL comp and I'm testing it...

I've a +6dB gain in bypass position... this is not ok I think ??!
All voltage (+/-15 +/-12) are ok
I made some try and replacing the NE5532 (output stage) I found one that doesn't make the +6 dB gain... I'm boght some other 5532 but I didn't try them yet...

Does anyone can give me some help???

--Another question.... the pcb rev 7 & schematic rev 5 are a little different in input and output connections?

i.e.: in the pcb the L+ go through two parallel caps and a 22K res into the 5534 pin 3 (+IN) but in the schematic the L- go into the pin 3...

Is it true?

please help....
 
6 db gain in bypass position is O.K. I think.

On the SSL schematic (rev #5) it sais:

"*15K Use 27K for unity gain when running unbalanced" so that for me explains the extra gain. I'm not sure it was 6db though...
 
[quote author="radiance"]6 db gain in bypass position is O.K. I think.

On the SSL schematic (rev #5) it sais:

"*15K Use 27K for unity gain when running unbalanced" so that for me explains the extra gain. I'm not sure it was 6db though...[/quote]


thank you. I'm working balanced, but 6 db between bal and unbal could be...


what about the input connection? this image can explain what I would say...
sch_vs_pcb.gif


the "red" path is the same in the pcb and schematic but in the pcb the connection is with the COLD pin (-) and in the schematic is with the HOT pin (+)
 

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