GSSL HELP THREAD!!!

[Twin-x]

Thank you Jakob!

 

[bubba_b]

This may be a dumb question, but I'll ask anyway. The parts list for the gyraf SSL give alot of Jaycar part #'s. I'm in the US, so I went through mouser to get most everything. All the resistors up to 1M are ½W, 1% metal film. How crucial is it that these be metal film? Would carbon work just as well and how important is it that they be 1% as opposed to 5%? All the local places I went either had 5% metal film or no metal film at all.

On a differrent subject, I got a milliameter that's a Simpson and has the # 20366 on the back. I got it at a reclamation center so no more info's available, other than it goes from 0-5 on the display and is DC. Is this usable for the GSSL? If a pic helps I can post one.

 

[Ian MacGregor]

Carbon resistors are fine. 5% is probably just fine as well. I would, however, buy 1/4 watt resistors and NOT 1/2 watt resistors. The PCB layout is a little cramped as it is.

Ian

 

[bubba_b]

Cool, thanks. That'll help with future projects. Anything you can tell me about the meter?

 

[mnats]

Most modern 1/2 watt metal film resistors sold today are the physical size of typical 1/4 watt carbon films and will fit in the SSL.

 

[bubba_b]

[quote author="gyraf"]For the meter to the SSL you'll need a linear 1mA fsd type, NOT a VU-meter.

....100uA, but will work with a different meter resistor (20K in stead of 2k)

Jakob E.[/quote]

So, if I'm seeing this right, it doesn't really have to be a 1mA meter, so long as it's measuring amps and has the correct resistor size on it? Suppose I have a 5mA meter (ok, I do have a 5mA meter), I would just need to change the resistor size to something like a 400R? Is that right?

Here's what it looks like if you wanna know:
http://pg.photos.yahoo.com/ph/adum_j/album?.dir=f470

 

[bubba_b]

bumpity-bump

 

[PRR]

> it doesn't really have to be a 1mA meter, so long as it's measuring amps and has the correct resistor size on it?

Yes, except there is some limit on the current. I don't have the plans handy, but if the meter comes from a chip, 10mA or 20mA is about the most you can be sure of. If you are in love with a junkyard 1-Amp meter, you can add booster-transistors (and a bigger power supply).

> bumpity-bump

What is this 2-hour bump?

 

[tubejay]

My GSSL Comp freaked on me tonight. It's over half as quite on one channel. I rewired the I/O jacks, checked continuity on all points, and the problem is still there. It was fine up until tonight. Any ideas why one side would all of the sudden get quieter? It still compresses everything just fine on both sides.

Any thoughts on this would be appreciated.

Cold solder joint??

 

[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.

 

[Emperor-TK]

I've read through this whole thread, but I don't think that I have seen the my exact problem discussed yet. I've built two GSSL's with the DBX's from Verbos, boards from Gustav. All my voltages seem fine, and metering and controls work fine. In fact, everything seems to be perfect except for a rather unmusical distortion that increases with the amount of compression. Bypassed, the units are passing pristine audio. I have tested both mainboards with the same control board, so either I made the same mistake on both mainboards, or my control board is the problem. I've run through the control board a couple of times and still cant seem to find anything wrong. I do have the jumper in place there as well.

Does this problem make sense? Is there some way that an error in the sidechain circuit could cause the signal VCA's to distort the audio that they are passing?

-Chris

 

[tubejay]

Which DBX VCA's did you use? Did you use a distortion trimmer?

 

[Emperor-TK]

Jay, I used the DBX c1252h2 from Mark Verbos. Turning the distortion trimmers fully in each direction didn't seem to have any effect, positive or negative.

 

[bubba_b]

Thanks PRR. So I'm guessing my math is right in using a 400R on the 5mA meter? Just don't wanna assume anything, but it makes sense to me.

 

[gyraf]

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

Jakob E.

 

[EEMO1]

umm.... just looked at the pcb and my parts, the parts list i use has 2x 1000u/63v caps but the pcb has 1000u/35v printed on to it...

which one is it? does it depend on something? i got to of both so i want to know which one to solder in...

thanks,

eero

 

[gyraf]

both 35V and 63V will work..

 

[daArry]

Hey bubba, what res value did you go with for ya 5mA meter then? I'm wondering on a appropriate one for mine - which is a 5mA meter too i believe (was 25mA but i removed this wirewound resistor lookin thing which knocked it down to 5mA)... how did u work out the value of 400R?

Cheers

 

[bubba_b]

Don't know if it works yet. I haven't heard back on if it's right yet, but I got 400R from what Jakob said about a 2k on the 1mA and a 20k on the 100uA. 1/10 the amperage gets 10 times the resistance, so I thought maybe it works the same the other way, ie: 5 times the amperage gets 1/5 the resistance. I could be totally wrong, but I'll let one of these other pros step in and verify. Anyone? Beuller? Beuller? :?: :grin:

 

[Ian MacGregor]

That makes sense bubba, BUT you have to make sure that whatever is driving the meter can source the higher current you are asking of it. I don't really know off the top of my head for the TL074.

Ian