GSSL HELP THREAD!!!

[dirk666]

Yeah ReggieReddogman I had thoughts along those lines too! But part of me also thinks you would learn alot less if there was a 'how to' guide as oposed to a 'why to'. Unless of course you see it as simply a way of getting a highly prized compressor for less dough. Nothing wrong with that of course.

 

[drumtan]

Yeah ReggieReddogman I had thoughts along those lines too! But part of me also thinks you would learn alot less if there was a 'how to' guide as oposed to a 'why to'.

I agree. I'm a complete newbie in the world of diy too , but i really enjoy
learning step by step , sourcing all the parts, find out 'bout different caps
etc..
That's part of the challenge even though a lot of patience is needed.
I like how people build there Gssl's different from each other , that's where the vibe and inspiration is coming from.
Would be too easy to have a step by step instruction :razz:

drumtan

 

[JD]

Guys,

Hi, hope you can help, and sorry if this has been covered elsewhere, I've had a look through the ssl help threads but not found any clues. Okay I'm making my second gssl - the first went fine and sounds great, but the second has a problem in the right VCA. Measuring the voltages on the pins of the 5534 (without the chip) I get ~-2.2V instead of -0.8V for both pins 2 and 6 - inv input and output respectively when comparing against my known good unit.

I'm checking resistor values and looking for shorts, but I'm a newbie and am a bit stuck so far. Can anybody give any pointers as to where look for the cause of this problem (left VCA voltages seem fine).

Thanks in advance...

 

[gyraf]

There's not much that can be said about that other than the usual: check for shorts, proper supply voltage, soldering, component values and component integrity..

Jakob E.

 

[JD]

Thanks Jakob,

I'm thinking a dodgy component, maybe. I don't have a capacitor tester at the moment so I'll probably try swapping a few of those out.

Cheers

 

[matthias_edp]

hi there!

I have a question about the TL074 TL072 and the 5532/34.

I have a LF347n instead of a TL074
for the TL072 I received a LF353n

and for the 5532/34 I received ap versions

are these the same chips I need but with a different partnumber? can I use these chips without worry. Or do I have to buy the correct ones?

 

[gyraf]

the 5532/34's are correct - only different pakage material. For the 072/4's - the LF's may work, but I haven't tried them, so there's no guarantees..

Jakob E.

 

[idylldon]

Turn it into a GSSL compressor:

Thanks for all the work so many of you contributed to make this project possible.

Cheers,
--
Don

 

[matthias_edp]

ok i powered up my ssl clone ands working. it is compressing the signal. all switches and pots are working.

only with a very loud hum.

i checked al components again if they placed in the good posistion. and also the values.

someone an idea where i can start looking to solve the problem?

 

[gyraf]

Matthias,

You just go through the usual steps, mentioned many, many times in this thread already.

Start out by checking your +-12 and +-15V supply lines for correct voltage and absence of ripple - and for distribution to all opamps.

Make sure that you have grounds connected properly to chassis and in/outs.

Then check for shorts, bad connections, and proper components.

Jakob E.

 

[matthias_edp]

i think i found the problem(or maybe part of it) the +12 volt regulator is an 7815 instead of an 7812. rs-components gave me the wrong one. and i probly didn't checked or something.

is het possible that some components are broken now? because of the 3 volt difference?

 

[gyraf]

No, it should be fine if you put in a 78L12. But check, check, and recheck all your other components!!!

Jakob E.

 

[matthias_edp]

ok I've checked a few things. The voltages from de regulators are ok now I think.

But not the hum is the problem also the very low volume that the clone gives. When I remove the vca from the sidechain. The volume is normal I think. I tried to replace the vca but that didn't help at all.

I have those dbx c1252 vca's(are there datasheets available somewhere, I can't find it on the internet. Only a japenase version). Maybe that is the problem? I also search for shorts or bad soldering but I think thats ok.

I also checked the values of the components. Thats allright too.

There's only one thing. When I powered up de SSL for the first time the 22u cap nest to the text on the pcb thats says "psu" exploded because of wrong polarity. I replaced it and also the 10r resistor next to it.
is it possible that I also have to replace the .1 cap between de 22u en 10r?
I think not because the voltages are allright. but maybe for the hum problem.

 

[gyraf]

the 0.1 polyester cap won't need to be replaced.

Are you sure you're putting in the sidechain VCA the right way around? Note that it is mounted opposite of the audio channel VCA's! Most often, the VCA's won't survive being put in wrong.

How much gain do you have from input to output, compressor bypassed?

Jakob E.

 

[tree]

:green: :green: :green:
I'm sure this is dumb and am sooo sorry to interupt.
The pots (threshold and make up) i got from mouser have no terminal markings....been searching meta for wiring info on potentiometers for gsl. Also read related Rod Elliots pages (great)....

If i'm looking at the front (knob-side) of the pot, is it true that farthest left terminal is #3 (+input), middle #2(wiper) and farthest right #1(gnd).

Seems so counter intuitive.

thanks anyone?

 

[drpat]

...

 

[tree]

um...
just to clarify question;
If turning pot CW, leftmost terminal position = post 3 (input), middle = 2 (wiper) and rightmost = 1 (gnd)?

thanks

 

[tree]

thanks. drpat...pictures worth a thousand words.

 

[tree]

After much checking and rechecking my solder joints etc, finally got to power up SSL board to check power rail voltages: + 15 reads at about 14.8 and can't seem to locate - 15 anywhere.
Transformer checks fine by itself.
The 2 big caps read at about +22 and -22. Is that about right? (using old small analog vmeter hard to get acurate readings)
Am wondering about 7915. Maybe toasted?

My first build, a bit disappointing...thought i'd been so careful...

Can someone confirm the best places on the mainboard to meter -15... any other suggestions or advice would be really really apprecited.
thanks all.

 

[chrissugar]

Before powering up it is a good idea to leave out the VCAs in case something is wrong, at least you will kill only some cheap opamps that you can find anywhere.
If you look at the PCB from the component side, you can locate somewhere in the midle of the board (between the transformer footprint and two VCA rectangles) two bypass wires, one is labeled +15V and the other -15V. Measure voltages referenced to the GND (for example the mid pin of the five pin input connector)
If everything is OK you can put the VCAs into the sockets.

chrissugar