GSSL HELP THREAD!!!

[Enchilada]

This may be quite a stupid question but here goes...

Kev's BOM list this as the 50K trimpot http://www.jaycar.com.au/productView.asp?ID=RT4316.

How on Earth are you supposed to attach a knob to one of these trimmers so I don't need a screwdriver to change the threshold or make-up gain? Can I not just use a 50K linear potentiometer like one of these? http://www.jaycar.com.au/productView.asp?ID=RP3516

Kris

 

[chrispbass]

This may be quite a stupid question but here goes...

Kev's BOM list this as the 50K trimpot http://www.jaycar.com.au/productView.asp?ID=RT4316.

How on Earth are you supposed to attach a knob to one of these trimmers so I don't need a screwdriver to change the threshold or make-up gain? Can I not just use a 50K linear potentiometer like one of these? http://www.jaycar.com.au/productView.asp?ID=RP3516

Kris

You've answered your own question
Chris
Chris

 

[Enchilada]

This may be quite a stupid question but here goes...

Kev's BOM list this as the 50K trimpot http://www.jaycar.com.au/productView.asp?ID=RT4316.

How on Earth are you supposed to attach a knob to one of these trimmers so I don't need a screwdriver to change the threshold or make-up gain? Can I not just use a 50K linear potentiometer like one of these? http://www.jaycar.com.au/productView.asp?ID=RP3516

Kris

You've answered your own question
Chris
Chris

Thanks Chris, you've been mighty helpful today!

One more quick Q though, most builds seem to be using a toroidal transformer. Am I able to save a few $$$ and use this PCB mount isolation transformer? http://au.element14.com/block/pt-13-2-15/transformer-13va-2-x-15v/dp/1711431

TBH, I don't know the difference between a toroidal and an isolation trafo, I thought a toroidal was still an isolation. Is that wrong?

Kris

 

[gemini86]

It's just the shape of the core...

They both isolate you from mains current, but the toroidal is better at keeping the EMI field down to a minimum because of it's round core shape. You may or may not have a problem using a regular core transformer, but placement of that transformer is more important to keep from getting HHUUUUMMMMMMMMMMMMMM....

 

[Enchilada]

Thanks for the info, I might solder one of those cheaper isolation transformers to a breadboard and put it in the corner as done here - http://www.gyraf.dk/gy_pd/ssl/exterior/overwiev.jpg

 

[gemini86]

if you have the room, do it.

 

[ptron]

hey !! is good to be back building stuff been out giging too much havent had time to finish this build that have been sittin in the studio.
im wondering if this one will work for my build. i used other model from same family for my previous 2 builds and it worked fine but just want to make sure

digikey TE62054-ND.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=104257016&uq=634512545211589171&DPU=submit

btw i got some of those igor´s 4x2181 boards and will probably need some help on that too when the time comes!! seems that i need to solder somewhere a trimmer im not entirely 100% wrapped around that idea.

thanks a lot!!

 

[jsefer]

I have just finished my build and have tried and tried to find my issue in this well documented help thread but I cannot find the serch terms or im missing something.

I built my unit w the DBX2150s, I have read all the material and the unit powers up, passes signal and sounds overal great. No humms, noises or smoke  ;D

My issues how ever are:

1. At threshold 0 and ratio 2:1 ratio attack and make up all at lowes value, the unit compresses, I asume it should not.
2. at ratio 4:1 and 10:1 the unit seems to be unresponsive, there is no change in audio when increasing the threshold.
3. Threshold adjustment seems to have little effect..


What I have tried:

1: I have double checked all my voltages, diodes in correct orientation, pc solder traces, orientation and placement of all ICs, capacitors, ect..
2. I have done the 47k mod at the threshold in hopes to have no gain reduction while at threshold 0, but unit still compresses.

I have spent 5hrs reading, and trying everything I can to help myself, and Im usually good at finding out my own issues.. But now Im going to bed, Its 2 am westcoast, USA and I feel great that Ive completed my project after 1yr in the making. Just want to thank everyone who has helped get this thing going, In the one setting that works, this comp kicks ass.

So I am going to bed happy, but frustrated that I cant help myself.. Hopefuly someone can slap some sense into me and point me in the right direction. tonight will be a sleepless night as I keep thinking what the hell is going on! 

If I cant get this thing going, my last hope is tracking some one down close to me, will bring beer and pizza for your time!



EDIT: I took out all my ICs and put them all back in and operation is good now, must have been a faulty contact somewhere, double check that peoples, THANKS TO GYRAF AND EVERYONE THAT HELPED GET THIS PROJECT UP, 7+yrs and people still building this amazing COMP.

 

[madreza]

Would a 2x15V 15VA be enough for feeding 2 GSSL ?  what about for 3 ?

 

[ptron]

Would a 2x15V 15VA be enough for feeding 2 GSSL ?  what about for 3 ?

Hehe i love monty python.. I dont think it can.. but i dunno really
Good luck on your build u making a few of em in a big enclosure?

 

[ncoak]

Greetings folks,

I recently returned to my GSSL to do some fine tuning; I've noticed that even with the threshold all the way open, the output is a few dBs quieter than when bypassed. I'm assuming this is some compression going on (meters do move a little but I'm also hearing some softening of transients).

Mine is permanently turbo'd, using THAT 2181LBs. In this lovely chart [http://diy.fischerworks.com/gssl_vca.shtml], it's recommended to replace the two 47k resistors by the VCA outputs with 120k resistors when using THAT 2181LBs. These 47k resistors are to be removed when installing the super sidechain boards, as they are included in the SSC boards themselves (I'm told). Might it solve my problem/help me out to replace the 47k resistors on the SSC boards with 120k resistors? I'm not great at electronics but pretty good at puzzles

I have just now added the 47k resistor to the positive leg of the threshold pot, which has improved things dramatically as far as control (not sure why I skipped that before). I have yet to do the 15k to 27k "unity mod," though it's next on my list (pretty sure this won't affect the issue at hand though, unless I'm mistaken).

Anyone have thoughts as to whether I'm on the right track, or found a solution to a similar issue? I've been loving the GSSL for a while but would really like to iron out the last few wrinkles.

Thanks!

 

[Enchilada]

Have you looked at this thread?

http://www.groupdiy.com/index.php?topic=34219.0

 

[ncoak]

I have - but don't think that's the issue I'm having, we're talking noticeably quieter (compressed) signal with he threshold all the way open.

I will probably do that one as well while I'm in there, though!

 

[ncoak]

Or not, as it doesn't seem to apply to the SSC bypass method which is relay based, i'm using a SPST switch for that.

 

[madreza]

Would a 2x15V 15VA be enough for feeding 2 GSSL ?  what about for 3 ?

Hehe i love monty python.. I dont think it can.. but i dunno really
Good luck on your build u making a few of em in a big enclosure?

Yeah I love monthy pythons

I wanna put 2 or 3 SSL Comp in 1 case , feeding it with 1 tranny.
I was wondering if 15 VA is not enough, 30 VA or 50 VA should be enough I guess !!!?
anybody knows ? any idea would be welcome

 

[ptron]

If u wanna do that also go to expat audio and look at the uber psu hehe looks loke fun maybe to add extra bits.. What mods u want for your builds? Standard gssl?

 

[kosty]

I managed to build the gssl incl turbo and SSC board.

I have faced several problems :

- the compressor acted very weird. I accidently connected the ribbon connector in reverse.
After correcting this the controls were OK.

- The signal sounded very muddy with almost no high end ! The problem was the 33pf capacitor on the input NE5534's feedback loop. Mouser gave me wrong values one's (33nf) which gave me a 220hz low pass ! Removed this cap and the sound is clean !

The last problem I'm facing is that I have a leak between left and right output !
Meaning :

- if I send a 1khz sine wave to the RIGHT input I have a A clean signal only on the right output.

- if I send this signal only to the LEFT input, the left input is normal BUT i have a signal also on the RIGHT output with a very high level (input of my interface is clipping !)

- everything happens in bypass mode.

- i removed the turbo and ssc mod from the signal flow

- i swapped both input opamps, vcas and output opamps, as well as the tl072 from the sidechain.

- 15v is 14.78 and -15v is -15.2

- if i remove the left vca the problem is gone ! (when sending only into the right input)

- I tried tracing the signal with my oscilloscope but it's not that easy visualizing anything on some part of the circuit.

- i have a very clear almost rectangular waveform with 1khz on the lower end of the 680k resistor next to the right vca when only left input is fed. (it's the 1 MOhm one I replaced because of that2181A)

- if I remove the NE5532 of the left input. Nothing arrives on the left input (logical).

I suppose it's a solder bridge somewhere but I have no idea where to specifically look. No obvious bridges by looking.

Any suggestions?

 

[schrobbelbop]

Hi!

I've noticed my left channel is oscilating on its output.. i only hear it when connect to a digital mixing desk (digico's)
at analog desks it's not hearable, but i see the vu meter lit up a bit. so it looks like a little potential on its output.
the amount and frequency of the oscilating ssl is depending on it's makeup gain pot.
anybody knows where to go searching?
I already swopped all vca's and ic's.... what to search for next?

thanks!

 

[ncoak]

Mine is permanently turbo'd, using THAT 2181LBs. In this lovely chart [http://diy.fischerworks.com/gssl_vca.shtml], it's recommended to replace the two 47k resistors by the VCA outputs with 120k resistors when using THAT 2181LBs. These 47k resistors are to be removed when installing the super sidechain boards, as they are included in the SSC boards themselves (I'm told). Might it solve my problem/help me out to replace the 47k resistors on the SSC boards with 120k resistors?

For the record, this doesn't fix anything

I've read through thread after thread in search of answers and came across someone who seemingly fixed this issue (Matthias):

"but I've got another idea ...  you don't need to change the witdth of the threshold range, you can "move" the range...  after testing I finally came to a quite useable result... 
solder a 22k resistor in series with the red marked connector on the small ssl pcb:
[http://www.cmaudio.net/forum/threshold-move.GIF]
when the threshold pot ist turned up to 50% of its range you have
0db when ratio is set to 10:1""

But of course the image is missing

No one else ever have this issue?

 

[kaptensarkasm]

Hey guys.

Just a quick question about my gssl:s psu.

I'm getting the negative rail spot on -15v. But the positive rail is about 3v. And it traces back to the bridge-rectifier.
The AC current is fine I think (16.6v)

Why is that? What have I missed?

Tried to search the forum and Google but nothing, and when I find something that could be it here on prodigy I've got limited access for some reason..


Cheers