GSSL HELP THREAD!!!

[Charly]

Hello everybody !
First thanks to Jakob for this GSSL project ! I built my GSSL (Rev#7) as first project and I have some problems, not surprised... My first problem was a wrong way 20uF, I replaced it and it seems everything still working !

Well I made my first test, sound is going in and out the GSSL but signal is very low and high pass filtered. I checked voltage values on every chip and there's some wrong values on the 3 VCAs and on the TL072 and TL074...
Thank you for your help

TL074CN
********************
0,06
0
0
12
0
0
-0,08
0,02
0,02
0
-12
0
0,08
0,37


TL072
********************
-3
0
0
-12
0
-0,04
-1,3
12


THAT Left
********************
0
0
-0,06
0
-2,8
0
15
0


THAT Right
********************
0
0
-0,06
0
-2,8
0
15
0


THAT SC
********************
0
0
-0,24
0
-2,85
0
12
0

 

[late]

If i build "new gssl" project with dbx202 gold cans. What i need do differently?

 

[Harpo]

If i build "new gssl" project with dbx202 gold cans. What i need do differently?

For both DBX202-C (gold can audio VCAs) use parts values from schematic and leave out both DBX202 emulation circuits (whatever a "new gssl" might be).

 

[gyraf]

I think "new gssl" refers to the latest revision SSL.PCB Rev#12:
Changes are
1) a simple sc insert jumper (remember to jumper this, or no compression will occur)
2) one extra layer of C+R in psu pre-regulation section
3) Additional optional +12V regulation for relays and lamps

Jakob E.

 

[Dias]

Hello everyone, this is my first time on the forum .
I'm trying to build the gssl but as everyone here I'm already having problems.

I'll try to explain as best as possible my problem.

When I turn on the compressor in bypass mode everything seems to work correctly , what I did was introduce a 1kHz signal at the entrance and from what I saw out exactly as entered . With only a small loss , but in terms of frequency and noise did not show anything new.

The problem appears when not in bypass , the dB meter automatically jumps to the maximum and output disappears.

I checked all paths 12V - 12V - 15V and 15V are all ok and all IC's are being properly fed. Also checked all the resistors , capacitors and orientation. I don´t find any errors at all. Also have tried to find short circuits buy again I dont see any.

So measured using the oscilloscope saw the exits of that2180 ( did the modifications indicated for use that2180 ) has a square wave ( pin 8).
The output 14 of the TL074 's practically remains negative but with repeated peaks in time. The tension in the dB meter is 10V.

Thank you all for your patience

My board is rev 7

 

[gyraf]

Mayne too high a gain in sidechain? Check resistor values (and for shorts)

 

[jicama]

Ok this is getting really frustrating, I've been reading a lot on theis thread but I can't find solution on my problem, basically nothing works on the controls, the gain and the led work momentanenly, but now nothing only passes the audio a bit stereo than normal, the voltage from the VCA's  on -15v I have almost -15 but where it says +15V I read -.5V, the 7915 reads -15v and the 7815 reads -.5v and some at the time it gets very hot them reads 15V I have changed but no solution, 78L12 and 79L12 gets very hot to touch as well and I read 0 on both. 

Any one can help this stupid newbie!

Thank you, I really appreciate it.

 

[jwhmca]

use your ohm meter to check the voltage rails for shorts to ground

 

[jicama]

Hey man thanks for answering, yeah I found shorts, couldn't see them with magnificence glass, but there is some kind of resyne is making beeps on my multimeter, I've been reading you can use alcohol to clean it, and some kind of tape that absorves soldering bolbs, ill buy the tape tomorrow, any more suggestions to fix shorts?

Thanks

 

[jicama]

Ok I dont think I can express my problems with words because of my knwolege at the begining at this project I didnt know what a resistor was but is very interesting indeed,  I really aprecciate if some one can guide me, I´m posting here my fisrt voltage readings but some of them i dont think they´re correct...

 

[Gustav]

Ok I dont think I can express my problems with words because of my knwolege at the begining at this project I didnt know what a resistor was but is very interesting indeed,  I really aprecciate if some one can guide me, I´m posting here my fisrt voltage readings but some of them i dont think they´re correct...

When you wrote "-0,5V" in a previous post, did you mean it was 0,5 lower than 15V, or did you mean you had an actual reading of -0,5?

If its the first, its not a problem, if its the latter, it can be a problem (Maybe just a latching regulator).

Your voltages around the regulators are fine. You measured a few points where I wouldn't know what voltages to expect, but overall, it seems to be fine..

Measure for the VCAs and Opamps as well, and if they hold up too, drop in the ICs and give it a twirl.

Gustav

 

[jicama]

Hi Gutav,
On the last post I was readin on the main rail -.5V I changed the 7815 and now this are my actual readings wich 2 of them seems suspicious
Marke it with a circle in both legs are reading "-01.5V"and the other next to it marke it with a circle is reading "0V" , regulators 7815, 79L12 and 78L12 are hot specially 78L12, led doesn't light...

 

[Harpo]

On the last post I was readin on the main rail -.5V I changed the 7815 and now this are my actual readings wich 2 of them seems suspicious
Marke it with a circle in both legs are reading "-01.5V"and the other next to it marke it with a circle is reading "0V" , regulators 7815, 79L12 and 78L12 are hot specially 78L12, led doesn't light...

The battery of your multimeter might be low.
Check for shorts and correct orientation of polarized caps that connect to the +12V rail on main pcb and control pcb as well as correct connection between these two pcbs, the wiering of threshold and makeup pot. Without ICs fitted on pcb, all of your voltage regulators shouldn't even get warm (total load on positive rails about 0.011A, even less next to nada on negative rails).
The not supply related "-01.5V" is not of interest for now. Measuring DC voltages at the IC supply pins in respect to 0V reference voltage is a lot easier to follow and respond to than measurements at electrolytic caps where you have to retrace the pcb to see their relation to supply rails.

 

[Greg S.]

Does anyone have a plan, where to measure what voltage?

gssl board revision 7

thx

 

[jicama]

Hello Harpo,
I found the gain switch having a problem making some kind of short, I dont know how but I changed it and regulators doesnt get warm now, I´ve been checking for another short but couldnt find anything as well are very dificult to find because there´s to many conections,
now power led works and here are my IC´s readings.

 

[jicama]

;D I inserted the IC's and test it with audio, now the controls works!! And sound awesome, although I'm not sure if it's behaving the way it should, specially the ratio.
And there still 2 issues my 10ma meter doesn't work at all, is dead, and sometimes when I switch it on led doesn't light, I have to switch it off and on again to make it work, we are almost there! This is very exiting!

 

[Harpo]

And there still 2 issues my 10ma meter doesn't work at all, is dead,

maybe. Is it connected with correct orientation to its current sensing (not illumination) terminals ? 0V is more positive than a negative control voltage.

and sometimes when I switch it on led doesn't light, I have to switch it off and on again to make it work

78L12 is latching on startup. Maybe read pg.300..303 from this thread for a latch up fix.

 

[Industrial Waves]

hi guys! This is my first project. What do you think about the soldering?

http://imagizer.imageshack.us/v2/xq90/716/yj7c.jpg[/IMG]]

 

[ding]

most look good to me. there are a few that need a bit more solder. they all need to look like nice Hershey's kisses and some look like blobby pancakes. but overall good.  dont forget to clean up that flux.

 

[jicama]

And there still 2 issues my 10ma meter doesn't work at all, is dead,

maybe. Is it connected with correct orientation to its current sensing (not illumination) terminals ? 0V is more positive than a negative control voltage.

and sometimes when I switch it on led doesn't light, I have to switch it off and on again to make it work

78L12 is latching on startup. Maybe read pg.300..303 from this thread for a latch up fix.

Thanks Harpo I fanilly had some time to work in this,
1.-Ok the problem on starting it up was because the 7815 I changed it to Lm317 now powering up solved it.
2.-Meter is moving but very shy, only a bit i dont think is reading full scale Im using 10 ma meter on the main board the resistor for the meter is 200 ohms
3- The main issue right now is the turbo board the voltage readings are not the way it should and I dont know where to look  :-\ I´ve already check conections and orientation of components, here i post some pics... I should read 12V at pin 4 and -12V at pin 11