GSSL HELP THREAD!!!

[spoontex]

I have a lorlin rotary switch. I wiring on the switch, because I want to disconnect the make up.

Thanks for the information.

 

[Potato Cakes]

A diagram for exactly that has been posted here a couple of times. You'll have to do a search for gain defeat bypass switch or something like that.

Thanks!

Paul

 

[spoontex]

The way that gyraf do in the documentation no?

https://ibb.co/rsh2C8H

 

[gyraf]

..yes..

 

[Rocinante]

Hey,
So I have built plenty of these. With turbo, with expat cap board, with transformers etc...
Here I have an older version board and I had the latch up problem that was "solved" using a solution that Harpo through out way back in the thread tying the output of lm78l12 to ground with an 1n4148. But now the 10r resistor is smoking. Through another suggestion found on this thread I increased the resistance to 100r. It helped as nothing smoked for 1 minute but then poof. The lm78l12 no longer gets hot but now that resistor burns up. I took out the led on the control board. I also used an external psi that uses 7815/7915. Any ideas?

 

[Rocinante]

I understand I am talking to myself (in a sense). So something in the 12v path is cold soldered or whatever. Damn everything but the 12v+ is perfect. I get nothing at the That 8180. I'll keep diagnosing. I messed up somewhere around there.

 

[Harpo]

..But now the 10r resistor is smoking.

A current limiting/voltage dropping resistor has a power rating. Maybe yours was insufficient.

Through another suggestion found on this thread I increased the resistance to 100r. It helped as nothing smoked for 1 minute but then poof.

Doesn't say much without saying what's the (probably too high) voltage in front of this resistor in respect to 0V reference voltage.

The lm78l12 no longer gets hot but now that resistor burns up.

Vreg getting hot is related to voltage differential between vreg input/output times current drawn. 10R or 100R resistor burning up is a too low power rating, caused by excessive power consumption of a f.i. broken 22uF cap in front of or after the vreg or a f.i. broken active device such as TL072, TL074 or the sidechain VCA. 

I took out the led on the control board.

Take out prementioned +/-12VDC operated chips as well and replace the burned up resistor. Rectifier will be operating correctly, else the other rails would have a problem as well. After powering on, if vreg still gets hot, replace the broken 22uF cap after the vreg. If resistor still burns up but vreg stays cool, replace the broken 22uF cap in front of the vreg. If resistor doesn't burn up and vreg stays cool, power down, refit 1st opamp and power on again. All fine, power down, refit the 2nd opamp and power on again. All fine, power down, refit the sidechain VCA an power on again....
good luck.

 

[Rocinante]

Harpo, thank you. So I was about to replace the 22uf as I ran out of things to go wrong. I replaced l78l12 and 10r and 1074, 1072 and put in spare 2501 (thanks to some POS behringer gear that was loaded with them). All my voltages are now perfect except... the 12v. I am getting nothing.  22uf cap getting replaced now.  And thanks again.

 

[Harpo]

... So I was about to replace the 22uf ...

There are two, one in front of the vreg, the other after the vreg...

 

[Rocinante]

So I replaced both 22uf. Once again no 12v but every other voltage is spot on.  I then replaced the 100r resistor I had in place of the 10r that goes to the positive vreg with a 10r again. And it smoked. But the 12v voltages were correct. Until i switched it off once I saw smoke.
Higher watt 10r?
Put 56r in there?
Tl074 was in but dbx2501 wasn't, as it's hard to check voltages with it in there.
Should I replace the .1uf wimas. They are rated at 100v and 63v.

 

[gyraf]

if your 10R smokes, then you're drawing way too much current.

Do the calculation: what does it take to smoke a 10R?

it's probably a ½w

so it takes maybe 2w to smoke it within reasonable wait time

2w into 10R is some 4.5V and 450mA <- as you see, there is something really wrong here

Something is taking up way too much current on your 12V line - either the 78L12 (+12V) regulator itself, or anything heavy-consuming you have put on that supply line:

Light? Relay? Dead opamps or VCA? Wrongly oriented diodes? Wrongly oriented electrolytics?


Don't use the 78L12/79L12  lines for anything but the sidechain and reference

/Jakob E.

 

[Rocinante]

Thanks Jacob,
Ripping the whole area out and retracing it again. I'll stick fresh op amps and vca's in there as well.

 

[Sinkia]

Hi everybody !

I'm finally ending building a really simple GSSL I bought from Gustav !

I just have one concern regarding the power supply wiring...
On his doncumentation, it show you have to make the secondary 30V, and the wire only those 3 points to the PCB.

I'm a bit of a junior, and I'm just wondering if this the right things to do ?

Many thanks all
Sinkia

 

[Gustav]

Hi everybody !

I'm finally ending building a really simple GSSL I bought from Gustav !

I just have one concern regarding the power supply wiring...
On his doncumentation, it show you have to make the secondary 30V, and the wire only those 3 points to the PCB.

I'm a bit of a junior, and I'm just wondering if this the right things to do ?

Many thanks all
Sinkia

check the blog on the site...

Gustav

 

[Rocinante]

Boy oh boy. Well no splitting atoms over here. So note to self; stuff all components at once, and if you don't then take notes. I got arrogant and overlooked the 1k resistors in the vca circuit.  That was dumb. I've built 3 or 4 gssl's and thought I should be able to do it blindfolded by now.  I was very wrong.

 

[Sinkia]

check the blog on the site...

Gustav

I will ! Thank you !

 

[Harpo]

I got arrogant and overlooked the 1k resistors in the vca circuit.

Nothing to do with your 10R smoking...

 

[Rocinante]

Nothing to do with your 10R smoking...

Well I also had the latch up problem with l78l12 and replaced everything that used the +12v line including the 78l12. The UA78l12 was the final one I put in there but maybe it was a number of things so I am not exactly sure if it was the UA or the tl072 or tl074.
It irks me not to know but it is what it is. I've also made a butchery of the 12v regs area as eventually I lifted every trace while replacing components. I ended up using legs soldered to legs in place of traces. It's really ugly but working. The gods of diy recording equipment will surely look down on me even more than they already do.

 

[gyraf]

Please note: 78L12 and 7812 are NOT pin compatible - pinout is reversed if you look at the marking, from the front

/Jakob E.

 

[Rocinante]

Boy oh boy I need to get my head examined. So I got it up and running but the regulators ran hot. So then while scratching my monkey head, I did what I should have done months ago; I checked the voltages on the supposed 15v unlabeled toroidal I bought off ebay.  18v!!!!  18 f****ng volts!! 
Now I know it's supposed to be alright to run the GSSL on 18v, but once I replaced the transformer with a 15v one, everything ran nice and cool. I have read countless times through the years members telling other members to check the transformer voltages before wiring it to the project.
So... Yeah. Killing it.