GSSL HELP THREAD!!!

[stereokillah]

with multimeter  check if some solder don't touch other  with a condictivity signal .
ofen it's under the opamp or around the input and output.

or perhaps you have an other risk like the first but you can't see it with your eyes.

 

[redmojosteve]

Hi, I am a newby to this although I did build a few guitar effects units years ago... It's great to see all this good work and mutual support.
Like many of the contributors here I have a bit of a problem.
I have built the GSSL clone but before fitting the semiconductors I checked through the voltages which seemed a sensible approach. The  +/- 12V are fine, +15V is OK but I am getting -16.3V which seems outside the spec. of the regulator. Curiously I am also getting
-26.4V on the heatsink of the 7915 which seems completely wrong. I have worked through the soldering and found two poor joints which I have rectified. Any idea what could be the problem? I am tempted just to replace the 7915.

I have obviously got the bug because I already have the PCB's and components for another SSL and also a dual channel G1176. However I think I'll get the first one up and running before I get too carried away.

 

[museic]

Sorry for the simple question but could someone just verify that this fuse is ok to use? Or do I need a different current value?

I'm in the U.S.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=486-1215-ND

 

[Harpo]

... but I am getting -16.3V which seems outside the spec. of the regulator. Curiously I am also getting
-26.4V on the heatsink of the 7915 which seems completely wrong. I have worked through the soldering and found two poor joints which I have rectified. Any idea what could be the problem? I am tempted just to replace the 7915.

Quite normal and ugly behaviour of 79xx regulators. This overvoltage (or is it called undervoltage as the number is negative?) will most probably drop to -15V with load (the op-amps) connected. Still leaving your op-amps out, you might verify this by temporarily plugging in a 1.5K resistor between NE5532 or NE5534 pin-4 and 0V. (Socket of Audio-VCA Pin-2 for 0V and the nearby 5534 pin-4 is an easy to reach spot for this test and keeps your hands free for further measuring) This will draw 10mA current as min.required load of >5mA for the 7915 regulator.
The -26.4 voltage @ heatsink is unregulated raw DC at input of your 79xx regulator.

 

[audiophreak]

  Hi All,
        I've only made it to page 50 of this thread, and have looked on Gyraf's site and have used the search option in the SSL Meta and on the Lab main page with no success.. :'(

  ... can some one point me to a BOM or a schematic for the Super Sidechain.... boards from Gustav, and maybe a short description of the differences of the Super Sidechain, Turbo board and Oxford options?

  much appreciated,
                          Chip

 

[audiophreak]

  OK... so I needed to search " sidechain" in sted of " side chain " - I found it..

  this is the page with the link for anyone else...

  http://www.groupdiy.com/index.php?topic=16113.120

 

[redmojosteve]

Thanks for the help Harpo. Loading up the output made all the difference. The 79xx regulators do seem to have a mind of their own. I have inserted all of the semi-conductors now and rewired the bypass switch which I managed to get not quite right. I'll try an audio input next and see where that gets me!

 

[angelo2979]

Hi there,

I come back after a long break, with the same problems on my gssl... I had to work in this period, but now I'd like to make this project work properly, and I would really appreciate any help...

the problem is that all the controls and the turbo switch don't work at all, except the make up knob and the bypass. But with the make up knob set to minimum (or with the bypass activated) the output signal is lower then the input...
the meter does not work at all.

I tried to replace the TL074 and Tl072, nothing changed...

as you suggested, I checked the voltages on my TL072 and TL074...

Pin 1 of the TL072, wich changes with treshold variations, goes from 2,99 to -0,08 v DC (but maybe it should be about 7v.. is there a problem here?)

at Pin 7 of the TL074 I should have the signal coming to the input of my sidechain, and I get about 0,98v AC

at Pin 8 of the TL074 I should have a DC signal coming from the output of my sidechain, But I have 0v

at pin 14 of the TL074 everything seems to be ok... it changes with the signal and ratio variations, and I have from -6 to 0,37v 


I just soldered all the components with maniacal attention, so I really don't understand where's the problem...

I really thank you for your help, hoping to find a solution...

 

[SIXTYNINER]

HI
please someone have some kind of picture
or scheme about
where/how get 12v power
for sifam vu meter bulb/lamp light?
(magic jakob said don't touch the 12v on the main pcb)
thanks in advance
6T9R

 

[trancedental]

HI
please someone have some kind of picture
or scheme about
where/how get 12v power
for sifam vu meter bulb/lamp light?
(magic jakob said don't touch the 12v on the main pcb)
thanks in advance
6T9R

See my post a while back http://www.groupdiy.com/index.php?topic=47.msg407025#msg407025

I used a resistor (1k5? as advised by Harpo ;D) in series from the 15V available near the the right VCA (Left VCA powered the Super Sidechain board) to power up my 12V LED Bypass indicator

See the attachment below for wiring up the SSC to get the idea!!! Just check the 15V voltages to confirm which connection is + /  -

 

[angelo2979]

any help for my problem?

 

[SIXTYNINER]

HI TRANCE DENTAL
thanks for post
my is not a bypass led
but a 12v bulb lamp that require more "energy" then a led
(later i post picture about)
6T9R

 

[trancedental]

If it's 12V DV required it should work fine, you could try a quick test first by connecting it to the Control Board 12V DC On / Power Off indicator to see if it works OK

Does the bulb lamp need more than 12V ?

 

[Harpo]

If it's 12V DV required it should work fine, you could try a quick test first by connecting it to the Control Board 12V DC On / Power Off indicator to see if it works OK

Does the bulb lamp need more than 12V ?

For Sifam meters these fastoon lamps come in 6, 12 or 24V with 3 or 5W. A 12V/3W bulb will have a current draw of 0.25A so a 78L12 with a max.load current of 100mA will probably not be that amused.

 

[SIXTYNINER]

If it's 12V DV required it should work fine, you could try a quick test first by connecting it to the Control Board 12V DC On / Power Off indicator to see if it works OK

Does the bulb lamp need more than 12V ?

For Sifam meters these fastoon lamps come in 6, 12 or 24V with 3 or 5W. A 12V/3W bulb will have a current draw of 0.25A so a 78L12 with a max.load current of 100mA will probably not be that amused.

as "Magic jacob" said:
don't touch the main pcb for "feed outboard parts"
then how feed this 12v bulb lamp?
6T9R

 

[Harpo]

as "Magic jacob" said:
don't touch the main pcb for "feed outboard parts"
then how feed this 12v bulb lamp?
6T9R

I'd try it between 15/0VDC with a voltage dropping resistor in series. (If you have to supply other circuits from the gssl, such as the turbo and/or sidechain filter(s), the 7815 might need a heatsink for this additional current requirement) Just ramping power up with a 12V/2W bulb (your part may be different, so look up the value engraved on the bulbs endcap), a 82 ohm in series seems to be more eye pleasing than a for my taste to bright 56 ohm or to dimmed 100 ohm. YMMV.
Alternative feeding it from your transformer secondary (this will be AC at whatever voltage) might need a higher series resistor value.

 

[Harpo]

Pin 1 of the TL072, wich changes with treshold variations, goes from 2,99 to -0,08 v DC (but maybe it should be about 7v.. is there a problem here?)

No. All fine. Have a look at the schematic. DC voltage at point "F" varies between +0.37V and -12V depending on dialed in threshold setting. This voltage is fed to an inverting amp with voltage gain set by the ratio of 56K/220K, giving ccw -0.09V to +3.05V in cw position at TL072 pin1. Numbers mighty vary a little as there is no perfect part and all resistors and such come with tolerances.

at Pin 7 of the TL074 I should have the signal coming to the input of my sidechain, and I get about 0,98v AC

No. Pin 7 is output voltage after the sidechain VCA. Seeing this 0.98V with input signal present, the sidechain VCA seems to be alife.

at pin 14 of the TL074 everything seems to be ok... it changes with the signal and ratio variations, and I have from -6 to 0,37v

So you reached point "C" (ignoring an unlikely failed open diode just before this point) 

at Pin 8 of the TL074 I should have a DC signal coming from the output of my sidechain, But I have 0v

So your problem is most probably in between these points "C" and pin 8. Check, if there is any voltage above 0V at point "D" with SW2 in its ON position. Case not, 1st candidate is a probably misswired bypass switch or if this switch SW2 is a lorlin, you might have placed the end-stop washer before turning this switch full ccw. 2nd best guess is a broken trace on your control board.
Case voltage arrives, I'd watch out for a short after pin 8 of the TL074.
Good luck.

 

[guitarguy12387]

Okay, i asked a bit about this before... but i still can't get it working, so i'll be a bit more specific. I'm trying to power the diypartssupply vu meter's lamp. Doesn't work in parallel with the power led. I already blew one on accident trying to get it to work lol. Anybody using this meter in theirs? How did you do it? Thanks so much.

 

[Harpo]

Okay, i asked a bit about this before... but i still can't get it working, so i'll be a bit more specific. I'm trying to power the diypartssupply vu meter's lamp. Doesn't work in parallel with the power led. I already blew one on accident trying to get it to work lol. Anybody using this meter in theirs? How did you do it? Thanks so much.

Correct me if I'm wrong, but I only see options "please select colour/white LED/blue LED", so this meter obviously doesn't come with a lamp but with a LED.
http://diypartssupply.com/index.php?main_page=product_info&cPath=3&products_id=3&zenid=125tm7ddo20ir8f3ofg8fau3g5

A white or blue LED most often come with Vf of about 3.4V and may have a If of 20mA or 30 mA that you don't want to exceed.
Feeding it from +15VDC and allowing maybe 15mA, the required series resistor value in ohm could be (15V-3.4V)/0.015A .... you do the math. If you want it brighter, allow for more current, but keep an eye on the parts limits.

 

[stereokillah]

guitarguy12387
check this link http://www.kpsec.freeuk.com/components/led.htm
it's bester to make the led in series and like Harpo explain you can find the good resitor value for your Gssl
check your voltage in your control board where you should put you wire for the led and you could do your calculation


SIXTYNINER  take the +15 and 0 on the wire transformer directly before the Board with resitor in series with the power led and meter led like harpo said.