GSSL HELP THREAD!!!

[onlymeeee]

From the horses mouth on gyrafs webite:
"The power supply part should be pretty much self-explanatory, the only weird part being that it's both +-12V and +-15V. The 12V's are used in the board as subregulators for obtaining predictable gains in case the main (+-15V) supply fluctuates."

A clean supply is important for the sidechain

 

[Kingston]

So I guess if I have a very clean and stable +-15 supply, I can completely skip the (unnecessary?) +-12 step.

 

[signalflow]

Thanks for that onlymeeee.

-Casey

 

[allinbang]

arrrrrgh  still have problems with distortion on the gssl (when I turn the threshold knob) but now I tried wiring the lorlin switch (that includes the bypass/on/off) differently and the ssl clone just has massive distortion no matter what I do. I feel like an idiot because of my lack of knowledge in this area but I desperately need help.

 

[thwop]

allinbang

I know very little about electronics from a design perspective. But a lot about manufacturing.

HAve you have checked all your soldering and component plavement(a checklist helps). If you have, check it again. I don't mean to be patronising, but if you are new to electronics there could be faults you have missed.  (Just like playing with a big bag of lego, that one little peice can be hard to see).
Did you use the THAT2180's, did you cut pin 4 off? And your voltages are all what they are meant to be.
After all this. I'd have a go at replacing the TL072 and maybe the 74 at a hunch. The threshold seems to be tied in to these components. They are not very expensive components and easy to replace, it could be worth a try.

BTW EVERYBODY. I still dont know what 22uf 25v electrolytic caps to buy. Please look at post on previous page for my issue.
What have people bought and where have they bought them. PLEASE, NEED HELP

 

[allinbang]

thank you thwop  I have now changed the tl072 and 74 and it does not seem to help (thanks for your suggestion though, it seemed logical) as I said before, once I start turning the threshold, the distortion starts end sounds like a mixture of distortion and like "a broken speaker" ; even when the threshold is turned to no compression, there is a slight distortion but when I stop the music that is feeding the ssl, the noise disappears completely ; also when I bypass the ssl and feed it with music, it is without noise.

Hope this can give someone a clue, as to what this might be and again sorry for my lack of knowledge in this area.

Allin

 

[thwop]

So would you say; more compression,  more distortion?

Is the distortion in both channels?

Can you swap the THAT chips around to see if it is one of them?(I do this to find faulty valves)

Looking at the schmmatic; My next guess would be somthing to do with the sidechain. I have heard simalar distortion to what you are describing when I worked at a company called Sebatron(look em up, nice valve preamps). It occured when the designer got to an attack that was far too fast. The compressor was trying to react to the individual peaks in the waveform.  Maybe a wildly fluctuating CV may have the same effect..

Sorry for the sparatic ideas
By the way, where did you get your 25v 22uf low esr electrolytic caps? No one else seems to be here.

 

[Kingston]

So I guess if I have a very clean and stable +-15 supply, I can completely skip the (unnecessary?) +-12 step.

answering to my self,

yes I could skip this, but I would have to recalculate the ratio and threshold resistances since they are referenced to +-12V.

 

[signalflow]

So I guess if I have a very clean and stable +-15 supply, I can completely skip the (unnecessary?) +-12 step.

answering to my self,

yes I could skip this, but I would have to recalculate the ratio and threshold resistances since they are referenced to +-12V.

Or try it with out changing the ratio and threshold and see how it sounds/performs.  Could be surprising, then again it could sound like total ass ;D

-Casey

 

[signalflow]

BTW EVERYBODY. I still dont know what 22uf 25v electrolytic caps to buy. Please look at post on previous page for my issue.
What have people bought and where have they bought them. PLEASE, NEED HELP

try these, http://search.digikey.com/scripts/dksearch/dksus.dll?Detail&name=P11213-ND,  they came from gregs parts list found herehttp://members.cox.net/ram3n/Greg_GSSLwFC.pdf

-Casey

 

[Stagefright13]

I am just an amateur so take this with a grain of salt. But I built 2 of these and the biggest problem is a small solder bridge on the bottom of the main board. Some of the pads are very close and can wick solder. I would suggest if all else fails use some solderwick on every pad that seem suspect. And check against the layout.

John

 

[allinbang]

Thank you very much both Stagefright13 and thwop these are really helpfull suggestions and I will try all of them (+going through every component and change what can be changed) and report back to you

Allin

 

[mikerisha]

I am just an amateur so take this with a grain of salt. But I built 2 of these and the biggest problem is a small solder bridge on the bottom of the main board. Some of the pads are very close and can wick solder. I would suggest if all else fails use some solderwick on every pad that seem suspect. And check against the layout.

John

i think the best solution for this is to make sure you get the smallest tip available for your soldering iron.  Also make sure your iron isnt too hot. make it just hot enough to get a good melt and not enough to burn the board.

I like to thread the resistor (or whatever) legs thru the holes, bend them in opposite directions, snip them really close to the board, place the solder iron tip on one side of the of the leg, and the solder on the other, until it melts and makes a nice round solder lump over the leg.  should look like a tear drop.

 

[slowbass]

Hello to all,
I've recently finished my first diy project, a simple GSSL. It worked almost perfect, good sound, no hum (thanks a lot to this forum) and then I wanted to screw the pcb in the box and fix minor things.
After that, I noticed the left channel was louder than the right one, so I tried to check solders and other things. Stupidely and newbily, I misplaced one NE5534 on the left VCA circuit (opposite side) and when I power the compressor... it blowed !
I've replaced the NE5534 and now, my beautiful GSSL doesn't work anymore :
- the power led doesn't light
- the sound is heavily distort with maximum gain
- all switches are inoperant

Where should I look first to try to fix it ?
Thanks very much for your help.

 

[Chrome Heart]

Hello to all,
I've recently finished my first diy project, a simple GSSL. It worked almost perfect, good sound, no hum (thanks a lot to this forum) and then I wanted to screw the pcb in the box and fix minor things.
After that, I noticed the left channel was louder than the right one, so I tried to check solders and other things. Stupidely and newbily, I misplaced one NE5534 on the left VCA circuit (opposite side) and when I power the compressor... it blowed !
I've replaced the NE5534 and now, my beautiful GSSL doesn't work anymore :
- the power led doesn't light
- the sound is heavily distort with maximum gain
- all switches are inoperant

Where should I look first to try to fix it ?
Thanks very much for your help.

I would start making voltage measurments from the power supply forward into the PCB. Something else got whacked along the way.

 

[slowbass]

Thanks for your help !
I've checked the voltages and I found one wire got unsoldered on the switch pcb... Now, the power led lights on but when I put the bypass in, the meter goes all way to the right and no sound gets out.

(In bypass mode, the sound is clean now, still louder on the left)

 

[Chrome Heart]

Thanks for your help !
I've checked the voltages and I found one wire got unsoldered on the switch pcb... Now, the power led lights on but when I put the bypass in, the meter goes all way to the right and no sound gets out.

(In bypass mode, the sound is clean now, still louder on the left)

I would check for solder bridges around the 5532 socket for the left. I think I remember having a similar problem a while back and that was the culprit. I pulled the pcb from the chassis to check it.

 

[slowbass]

So I've checked the solders as you say and now, the problem of different levels in bypass mode has gone ! Thanks !
But the GSSL still doesn't work properly. The signal seems overcompressed, only with a slow attack I can hear something on the loudest parts. (don't know if I'm very clear !)
Could it be a problem inside one lorlin switch ?

 

[Arrigotti]

Here is a quote from the Gyraf site.  Hope this is helpful:


PROBLEMS WHEN BUILDING:

If you read through the related error-fixing thread at Groupdiy.org, you'll see that the errors that the average DIY'er encounters when taking this problem on is limited to a few categories:

- Solder blobs, shorting PCB traces. The layout is very tight at places, so do yourself a favour and check and double-check - preferably with a magnifying glass.
- Bad soldering, not giving proper contact between component and PCB trace.
- Wrong component types or values. Specially error-of-magnitude on resistors.
- Wrong orientation of components. Including capacitors, IC's and diodes.
- Wrong wireing.
- Last, it's (for reasons unknown) common to forget mounting the wire-link at the control pcb, right beside the meter connection. This results in gross distortion in both channels.

 

[slowbass]

Thanks for your help but I've already searched on the forum and on the Gyraf site, of course, my first source of information !
I've checked all of these problems mentioned there. In fact the GSSL used to work so I think the components are rightly placed etc... 
Now the compressor doesn't work anymore (after I blew a ne5334, right VCA) so I'm trying to figure which other component might have been damaged... For the moment, I can't find it. I thought maybe someone knows what would cause the bad behaviour of the GSSL after I described the symptoms. Maybe you have an idea ?

(I'm a newbie in electronic so sorry if I ask newbie questions on the "SSL help thread" which I've read...)