GSSL HELP THREAD!!!

[rbaker]

OK I think I found it...I saw a thread somewhere and it recommended using a flashlight on the component side to spot shorts.

There's a TINY little bugger between the ground of the 79l12 and the input voltage of the 78l12....which would mean all the input voltage would be going out to ground right? I checked around that soo much, but there's some flux on top of it and made it look ok.

I'm waiting for the iron to heat up and then I'll try it again.

That flashlight trick is awesome.

 

[rbaker]

everything checked out and it's working fine.

I have a question though---I'm running RMAA and doing some comparisons...

What influences the THD the most in the circuit? The ic's seem to have a little effect on it but not much.

(between mine and my friends unit, one has .159% and the other has .019%...I'm sure this is totally ok, especially in this circuit)

They both sound fine, I'm just trying to understand the circuit a little more. I know the 15v rails in one unit are a little better than another (-14.99/+14.60, and -14.99/+14.87) Could this effect it?

I'm sorry if it's a can or worms.

 

[dissonantstring]

hi ryan,
theres a DIST trim pot next to each of the L/R VCAs (the 50K trim pot with wiper connected to a 1M resistor). you can try adjusting this and then measuring THD. hope this helps.
-grant

 

[rbaker]

I have the 2180LA's so they are pretrimmed (A should be the best specs for pretrimmed versions right?) I don't even have the trimpots or 1 meg resistors installed.

Is it all on the VCAs? maybe there's just some not-so-great soldering on one of the boards. I'll check it out.

I could also try switching out the vcas from the low thd unit to the high thd unit.

 

[morpheusmultimedia]

Hi everybody,

this is my first thread as well my first DIY project (building 2 GSSL comps rigth now) so forgive my stupid questions :wink:

I would like to have the on/off and bypass functions controlled by push buttons insted of the rotary switches. I was reding the forum that for the bypass I will need a DPDT switch - I have found some nice illuminated switches on the http://www.nkkswitches.com website - my question is are theese suitable for

bypass - UB225KKW016B-3JB (DPDT )
on/off - UB215KKW016B-3JB (SPDT)

there are 2 versions of each labeled

SPDT ON (ON) vs SPDT ON ON () = Momentary -what's the difference between them ?

also were could I find how to wire that bypass switch

many many thanks in advance

david

 

[morpheusmultimedia]

come on isn't there somebody who will answer my stupid questions :grin: :?:

thanks :green:

 

[sonicwarrior]

I think the ON in brackets means a momentary switch
which is not what you want here normally.

Edit: "Momentary" AFAIK means that it gets back to the normal position when you don't press it.
In german: Taster (momentary) vs. Schalter

 

[3nity]

i just finished 2 GSSL on one case power it on before rack them!
Nothing smoke nothing went wrong all leds powerd it up.....What do you guys use as test? i was thinking to plug the monitors out of my 002R to gssl ins and outs from gssl to monitors is that cool??

i read the Gssl thread and not an answer...

 

[3nity]

ohh wait this one better? outs 1 and 2 from 002R to GSSL, GSSL to ins 3 and 4 for better monitoring??

 

[dustbro]

Can someone help me do some quick trouble shooting?
Here's what I have going on.. Gssl with all 2180LB chips. The 47R resistor on pin 4 of the sidechain 2180 is pulled, All components on pin 4 of the 2180's in the channels are pulled. and the 3.9K resistor is properly replaced with the recommended 5.1K resistor. Greg's Sidechain is installed.

My threshold pot was acting like a volume knob. In other words, the attack, release, and ratio were not working. So after some research I replaced the 100K resistor resistor in the sidechain to the 127k* as noted on the pdf. At that point my unit would have bursts of compression every 3 seconds or so. Then I experimented with replacing the 127K* resistor with other values and found that a 33k resistor works the best. The unit seems to do what it's supposed to do, but compaired to my 4000G console bus compressor the GSSL is lacking upper mids and top end. most likely has to do with the above issue.
Can someone point me in the right direction? What could I have fucked up in the signal flow before that 127K* resistor that would need me to drop resistance before the VCA?
Just another bit of info... My pcb has labeled 15K resistors just above the VCA circuits and the PDF shows them as 27K. Should I swap out the 15k resistors for 27K?

TIA

 

[stefan]

I´ve been using my ssl comp clone for maybe a year or so and it pretty much does what I expect it to do every time, no hum, and it affects the sound the same way the original in a 4000E console I´ve used on a couple of occasions, so far so good. One problem with my unit is that when I use really light compression the output is too hot! Makeupgain knob all the way CW and i Would like it to bee maybe 6dB lower in output, is there an easy way to solve this?

 

[bluezplaya]

I am trying to trace the signal path in my SSL clone to get it working. I am running a test tone through in the input and from the left input I trace just as far as the first 22k resistor. Now, with the power off, I get a mild signal drop across the resistor. But when I power the unit on, the signal drop is a lot more significant and it is very quiet. Can anyone explain this?

Adam

 

[radiance]

[quote author="bluezplaya"]I am trying to trace the signal path in my SSL clone to get it working. I am running a test tone through in the input and from the left input I trace just as far as the first 22k resistor. Now, with the power off, I get a mild signal drop across the resistor. But when I power the unit on, the signal drop is a lot more significant and it is very quiet. Can anyone explain this?

Adam[/quote]

I had a simmilar question which I asked in this thread. I think the answer to your question has probabely something to do with voltage to current conversion......

 

[living sounds]

Hi everyone,


I just powered up my GSSL (only the mainboard connected, no ICs) - and the 1000µF power caps blew right up. I had only started measuring the voltage - it was showing 15.4V and then climbing upwards to around 16V when the first one - and then, while I was fumbling to disconnect power - the other exploded. I'm pretty sure I had the polarity correct (though I somehow managed to forget checking when I desoldered the - now useless - parts). Measuring the voltage from the unconnected toridial I read 17V.

Any ideas what to check? I will be able to get new caps tomorow. A little help would be great!

Thanks,
Gregor

 

[Whizard]

I am willing to bet on that you put the electrolytics in backwards.
Either that or a massive overvoltage is necessary for them to blow like that. And you do not seem to have an overvoltage problem if you have got 17 volts from the transformer.
Also check that you have DC and not AC over the capacitors - check that the diode bridge is OK.

[quote author="living sounds"]Hi everyone,


I just powered up my GSSL (only the mainboard connected, no ICs) - and the 1000µF power caps blew right up. I had only started measuring the voltage - it was showing 15.4V and then climbing upwards to around 16V when the first one - and then, while I was fumbling to disconnect power - the other exploded. I'm pretty sure I had the polarity correct (though I somehow managed to forget checking when I desoldered the - now useless - parts). Measuring the voltage from the unconnected toridial I read 17V.

Any ideas what to check? I will be able to get new caps tomorow. A little help would be great!

Thanks,
Gregor[/quote]

 

[living sounds]

Yes, but I must have put both of them in backwards in order to blow up, musn't I? I just can't seem to think how I could have managed that...
The diode bridge is soldered in with the plus side (the longer leg) orientated towards the plus sign on the PCB. Can I safely measure the voltage after the diode bridge without the 1000µF caps soldered in?

Also, is it possible that I connected the power input wrong? I had the two AC lines soldered in in pairs rather than alternating.

Thanks alot!

Gregor

I am willing to bet on that you put the electrolytics in backwards.
Either that or a massive overvoltage is necessary for them to blow like that. And you do not seem to have an overvoltage problem if you have got 17 volts from the transformer.
Also check that you have DC and not AC over the capacitors - check that the diode bridge is OK.

 

[gyraf]

Yes, but I must have put both of them in backwards in order to blow up, musn't I? I just can't seem to think how I could have managed that.

Could also be the bridge rectifier mounted wrong way around - CHECK!!!

Jakob E.

 

[living sounds]

Yes, but how? I'm sure I soldered it in with the "+"-symbols on the component and the PCB overlapping. Is there a way to check the voltage coming from the rectifier without having the caps solderd in?

Yes, but I must have put both of them in backwards in order to blow up, musn't I? I just can't seem to think how I could have managed that.

Could also be the bridge rectifier mounted wrong way around - CHECK!!!

Jakob E.

 

[living sounds]

Hi again,

turned out you were right (thanks again!), I had the electrolytic caps soldered in the wrong way. All of them. Mixed up the orientation with the tantalums I had soldered in before. Stupid thing to do really - but equally stupid to have different denotations for different sorts of caps, I think...

Now voltage reading at the central +/- 15V measuring spots is almost ideal (there's a slight tilt to one side, but less than +-0.1V).

However, a few measuring spots are showing wrong values:

The -12V spot at the top reads -22,6V

The +/- 15V spots at the bottom both read 0V


The +12V spot is slightly off (+12,2V)


Thanks for your help!

Gregor

 

[Silvas]

HI

Thanks jakob for your wonderful project.

I´m from Colombia and i´m building my first gssl, having to fit many locally available parts to do the work (no lorlins here but some kind of rotary switches that can be fitted nicely with some work!). I´ve used the gerbers from Jakob´s site to have a local pcb mfg. company make me the pcbs, they came out beautiful at a great price (i´ve merged both pcb files into one so the job is cheaper at least the first time, around 25 usd, next ones will be cheaper).

I´m planning to put a 20 segment led gr meter with switchable scales (5/10/20dB) i´m working on...

Jakob said is ok to use one of these, as gssl outputs 0.1v/dB...

if i were to use one of these, do i need to mount the 2k meter resistor? another value?no resistor at all? my meter scale will be 2 volts completely deflected, all leds on. I don´t know what to do, as i think the 2k resistor is a current (not voltage) limiter ?

i´ve printed this whole thread and learned alot

thanks!