GSSL HELP THREAD!!!

[Greg]

To answer breifly, anything inside the boxes take out and everything outside the boxes leave in.

 

[tommypiper]

Hi Greg, thanks. Including the trimmer pots - they stay?

 

[Greg]

Correct, they're outside the box, right !?! :green: :thumb:

 

[tommypiper]

Yes, and they're connected in the schematic as if using dbx 202s.

But I saw a photo of yours, or someones with 202s and the trimmers were not there, so making sure.

Also, there is no space to fit the 202s on top of the trimmers where they overlap, as the 202 pins are not long enough to reach the pcb!

(The pins also do not fit into the holes, did you find that too? Why put 202 holes there if they won't allow the 202 pins? What was he thinking? I have some real questions and issues with this board, but never mind.)

 

[tommypiper]

OK, got it together and I'm back where I was before. Passes audio. Compression is grossly distorting at virtually every setting. As soon as compression is dialed out with the threshold pot the audio cleans up to normal again.

Any ideas? What would cause that behavior? I've been all over this board over many months now. I'm really at the end of my rope. I've replaced parts, doubled, triple checked, etc. How can I troubleshoot this now?

One idea is a broken trace I fixed with a jumper on the bottom of the board (I did not build this unit). Guys, can you check to see if you get continuity between the two solder joints as pictured in the photo? (the two solder joints circled at top of purple jumper, big arrow)

If your board is mounted, you can also check this at Pin 3 and Pin 6 of the Sidechain VCA. You can check with the VCA in the socket, and power off. Takes a second. Do you get continuity between Pins 3 and 6?

I really need some ideas how to continue. Thanks to all.

 

[gyraf]

Compression is grossly distorting at virtually every setting. As soon as compression is dialed out with the threshold pot the audio cleans up to normal again.

Any ideas?

Check that the often-forgotten jumper at the control board - just above the cable - is in place...

If it's not this (it usually is ), then check waveform at your "timed" cv, coming from the Attack/Release circuits..

Jakob E.

 

[tommypiper]

Thanks. Do you mean the CV coming from here after R58?

And entering here at R10?

Which I measured here at the 1K below R9 which I believe is R10?

I got a lot of different wave forms, depending on the level being fed. On longer releases I got a flat line, even while the meter was showing compression.

Low compression wave forms:
http://i82.photobucket.com/albums/j243/tommypiper/P8311058.jpg
http://i82.photobucket.com/albums/j243/tommypiper/P8311064.jpg


High compression wave forms:
http://i82.photobucket.com/albums/j243/tommypiper/P8311071.jpg
http://i82.photobucket.com/albums/j243/tommypiper/P8311073.jpg

Pushing the input level to extreme limits it became a halfwave:
http://i82.photobucket.com/albums/j243/tommypiper/P8311063.jpg

Does this mean I'm only getting half rectification?

 

[dustbro]

Can anyone share a mouser number for their Power and bypass switches? I got the rack from Purusha and the Lorlin switches dont fit... I kinda wanted a flip switch anyway. Which ones did you guys end up using?

 

[Greg]

First you need to know the diameter of the hole... unless you're willing to drill out a bigger one if need be. Then head on over to Mouser. I like these and use them often, MTG206N, but they're very hefty and I doubt they'll fit in Purusha's holes. Nonetheless, search for toggle switch DPDT and companies like C&K and Alcoswitch are very reputable.

 

[dustbro]

Thanks Greg! Would you use your suggested switch for both bypass and power? I read earlier in the thread to use a "real" main switch for the power... I guess my questions would be what specifications do I need to look out for to determine if a switch can handle the job?

 

[BR]

Hi guys,

I was messing around with my (unfinished) comp yesterday and noticed a strange behavior.
I was tracing the signal with the scope from the input pin all the way to the input of the VCA.
First I tested without any VCAs and everything looked fine until Pin1 of the 2181s.
After I put the 2181 in the socket everything was fine, except at Pin1 and the 27K (trim pot, in my case) right before the VCA. The wave form was clipped; chopped off on the positive side.
Has anyone experienced this?? does this mean I have a bad VCA.

I checked all the pins for proper power and they all seem fine.

thanks
Gil

 

[Axelerator]

Ok. there again. after reading all of the ssl threads i have discovered
(i hope..) all the differences between the pcb layout and the v.7 schemo on
jakobs site . I did the whole thing point to point (not from the silkscreen , just
puzzled together from the schemo..) and now i see that the two opamps inside the 5532´s on the output driver have been swapped on pcb..
so this should be no problem since the opamps are equal?
( i went 2/3/1--> 6/5/7 in the outputs )- ..would prefer not to desolder this lavalike kludge.......!

Greets , Axel

..the other changes should be no prob..

 

[gyraf]

so this should be no problem since the opamps are equal?

Yes, there may still be small differences between schematic and PCB - mostly because they're part of different processes in my mind

The PCB's are however checked and verified. Several times. Quite a few people have built these over the years..

Jakob E.

 

[Axelerator]

Hi jakob , yes should have done it on pcb..but was BIG fun !!
- just waiting for my vca´s to fire it up , very exited!
Ax.

 

[gyraf]

..but was BIG fun !!

Now THAT'S the spirit!!!! :razz: :thumb:

Jakob E.

 

[tommypiper]

Jakob, thanks for the PM. Did you see my post on page 119? Was I checking in the correct place? Did you see the waveforms? Am I supposed to be getting a halfwave or a flat line... or?

Could the broken trace I corrected in the picture be causing these problems? I'm having a hard time testing it. Looking at the layout I expect one continuity result, but testing gives me another. It's possible components are making the link, but I don't see it. (Pins 3 and 6 Sidechain VCA.) What is the correct result (with components in the board)? Would anyone be nice enough to check what they are getting on a healthy board?

 

[JAYJAYBEE]

Hi just checking if this is a suiteble bridge rectifier for the ssl project

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=7355440

thanks

 

[JAYJAYBEE]

and the regulator

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?sku=413070

 

[sintech]

JAYJAYBEE.

Not sure about that regulator. It's also no longer stocked.. and the suggested alternative is (part number 413082) is £5.93 a piece!!!! ouch!

I'd go for this!!:

http://www.musikding.de/product_info.php?cPath=60_78&products_id=350

0.15 EUR

 

[sintech]

JAYJAYBEE.

Regarding the Rectifier: Thats a surface mount type, no good for the Gssl.

This is the correct part:

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=1017877