GSSL HELP THREAD!!!

[fum]

Ok, final update. I've got both my SSL's working finally. The final problem had to do with a faulty 202 VCA in one channel ( would pass audio at a lower level, but without compression).

They are both happy now. Time to rackem! Thanks Jakob!

ju

 

[tubejay]

[quote author="radiance"]Yes, a cold solder joint might be it. Did you work on your SSL lately?
One time I had a similar problem and it was caused by a very small piece off wire which produced a short. Probabely came off when stripping a wire.[/quote]

I bet we had the same pins shorted. I had pins 2 and 3 or 1 and 2 shorted (I can't recall which it was now) on my 5532 output amp. It was caused by a little fleck of solder. It does not appear that I have done any permanent damage. I fixed the short, and it sounds perfectly fine to me. I have yet to do a thorough test with some tones at the studio, but it appears to be fine now.

So if anyone has a similar problem (one channel quite a bit quieter than the other but still compressing just fine), check pins 2 and 3 or 1 and 2 of your 5532 output on the quiet channel, to ensure there is not a short.

Thank you Radiance for giving me a good starting point!

 

[Emperor-TK]

TK - check if your timing circuit (attack/release) is working right..

Jakob,

I finished my second control board and replaced the original. The problem is much better, but I still have some distortion on low frequencies, particularly at short attack/release settings. I know that it is common for some compressors to distort on low frequencies with short attack/release, but I am testing with a sine-wave audio generator sending a constant amplitude tone through the system. This time I could hear more distortion with the trimmer adjustment, but I couldn't get rid of it all. Any ideas?

Thanks,
Chris

 

[tmbg]

just got my PCBs from gustav, they look fantastic, but CRAP! I got 3x4 switches, and I needed 4x3!

 

[bubba_b]

I hooked up my transformer. I have the same type as tubejay has and I hooked it up like this (per this forum):

• purple/black to power inlet +
  red/yellow to power inlet -
  on the secondaries, red/brown together

Then I measured voltage between blue and green. It's supposed to be approx. 30VAC. I measured about 38-39VAC. Is this acceptable? How close should it be? Seeing as how there's nothing else in the box except the IEC and trafo, this should be pretty easy to troubleshoot. :grin:

 

[Ian MacGregor]

Is the measurement you made RMS or peak? Also, consider that the mains voltage can vary quite a bit (~30%). Also, the voltage you measured is the no load voltage, which will be higher than the voltage under load (This is probably the main reason why you are seeing a high secondary voltage). I would build the board and give it a go.

Ian

 

[bubba_b]

It was RMS. I didn't think it was faulty, just wanted to double check. Thanks, Ian. I'll be back with updates, etc. once I get the board going.

BTW...this place is great. You guys are so helpful. If I could, I'd have my grandma make you all cookies.

 

[tmbg]

My first GSSL is stuffed, waiting on the power transformer. Bought a box and an edge meter from Ack today... This meter just happened to be their only edge meter in the place, and happened to be a 1mA DC, and is in a box that suggests it's been on the shelf for 30 years

Tonight I'll likely handle the drilling and such fun stuff, maybe make wiring harnesses for the control board and the in/out jacks.

Also I bought some teeny 12VDC light bulbs, thinking I would drill (or melt) a little hole in the back of the meter housing to illuminate it. Will a 12vdc filament lightbulb introduce any noise into the power supply? I guess I probably shouldn't run it off the regulated 12V, since a) it may disturb the control voltages, and b) the bulb draws 60mA, and 78L12 only provides 100mA if I remember correctly...

So, is it kosher to use the rectified and unregulated 15+ volts pre-7815, and if so, do I need a resistor to make up the voltage difference? Will that affect my power?

 

[Greg]

Exactly, use the rectified, but unregulated VDC for the bulb, with the appropriate series resistor.

 

[keithcamilleri]

hi guys....

I have two comps in a 1 case.. 1 of the comps when I put an input to the left XLR and an output on the right XLR it passes audio whilst the other one does not.... has anyone got the same problem?

both compressors, compress and work well but I'm curious to see whetehr this is normal or not?


thanks

 

[gyraf]

Keith,

You'll need to explain that again...?

Jakob E.

 

[giobinein]

I'm bulding the SSL clone (thnaks for the project gyraf !!!) but here in Italy I can find only the THAT2180LC; is good or bad for this project ??
Thanks !!

 

[gyraf]

Giobinein,

They'll work fine. They're much better than the old DBX2150 anyway.

Jakob E.

 

[giobinein]

thanks gyraf :thumb:

 

[keithcamilleri]

ok gyraf..

its a bit difficult to explain...I am using 1 input xlr wire and 1 output xlr wire for testing single channels.

On the first compressor when I connect the left input xlr and right output xlr audio passes... :roll:

on the second compressor I have to connect left input XLR to left output XLR for audio to pass if I do the above configuration audio won't pass.

I'm not sure which one is behaving as normal.

Hope this is a bit clearer.

cheers

 

[gyraf]

You have probably just switched the two channels on either input or output XLR's?

Jakob E.

 

[keithcamilleri]

hi jakob...

I thought of that too...but both outpus have audio in them when either the left or the right input has a signal in.


any ideas? :?

 

[tubejay]

Did you do a continuity check between the pins on your outputs and inputs to see if you've got a short somewhere? Sounds like it could be short. I'd do a continuity cross check between each and every pin (and every combination) on the ins and outs to see if that's the case. Also check the top side of your PCB to make sure a stray little wire didn't work it's way over to short out to the other side.

 

[Emperor-TK]

I think I might have discovered the source of my distortion. After reading the data sheets from THAT corp, I decided to check for AC in my sidechain. I found AC on the CV inputs of the signal VCA's that was directly proportional to the distortion I was hearing. When set at low attack and release settings, the AC went up (from 5 to 10 mV) and the distortion went up. The AC was also higher for lower frequency sine wave inputs.

Of course, the AC throughout the side-chain was larger or smaller, depending on where I measured. I traced it all the way up to the TL074 opamp. I am getting:

0.0 VAC at "A"
0.96 VAC at "B"
0.022 VAC at "C"
0.015 VAC at "D"

I seem to remember reading in the Meta that the TL074 section here is a rectifier? I assume that I shouldn't be seeing any AC at point "C", or is 22mV considered insignificant? I'm still a newbie, and I dont fully understand what's happening in this section of the sidechain with the opamps and diodes. Any suggestions would be appreciated.

-Chris

 

[BackHand]

Hello!

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: :?: :!: