GSSL HELP THREAD!!!

[Harpo]

The problem with the 12v rail disappearing upon startup sometimes persists, though.
I changed the two 1000μF electrolytics to 2200μF, that reduced the problem a lot.
Now it does it 1 out of 6 times or so, whereas with the 1000μF it did happen a lot more frequently (like 50% chance each time).
I also tried the psu mod that angelo suggested (with the 2 ceramics 100nF/50V and the 1N4007 diode), and it did nothing noticable. Should I remove the mod since I can't notice any difference? Or is it actually better to leave it on?

and ultimately, what am I going to do with the powerup problem? I think just going with bigger caps is plain wrong, although it is a workaround, this is a problem that has to be fixed, not camouflaged.

A 1N400x diode, anode to 0V, kathode to 78L12 +12V output should help the regulator from hanging at power up. (similar to the fix you refer to, but for the +12V rail.) Your described fix is for the +15V rail latch-up problem. No need for a 1000V diode rating. , any 1N4001, 1N4002,.. you can get should do.
The 100nF caps at 7815 and 7915 input, as drawn in schematic, are placed at 78L12 and 79L12 input on pcb instead and now might be missing for the 7815 or 7915 if these oscillate for whatever reason.
Of course you will not notice any difference with a +15V regulator latch-up fix when you need this fix at your +12V regulator. 

 

[ytsestef]

OF COURSE!!!

I have no excuses! I am very careful most of the time, why wasn't I focused when doing this one? I knew the problem was in the 12V rails and I know the difference between 7x15 and 7x12. Hell in this design they're even in a different package! DUH! Very reckless...  :-[ :-[ :-[ (second request for facepalm emoticon). Thanks for pointing that out!

I already have a couple of 1N4007's lying around, so I guess I'm gonna use these ones...
Harpo, I am no electronics expert, I barely know how things work, I am just a guy with a soldering iron... so:

1N4007's anode to 78L12's middle pin
and
1N4007's cathode to 78L12's output

and remove the 7815 modifications including the two extra caps altogether? Is this what you meant? (I don't really know their purpose, see)

 

[Harpo]

yes. Between the +12V wire link next to the 78L12 and any other spot at the bigger 0V pcb traces seems more comfortable to solder on. Its a little tight at the regulators pins and you don't want to make a short.
No need to remove your 7815 modifications, though moving the added 100nF between 7815 output/gnd to 7915 input/gnd might be more useful as you already have the cap.

 

[ytsestef]

OK, I will do that Harpo, THANKS!!

EDIT: Did it and it still happens...  
At first it seemed that the problem was gone, I powered up 20 times and it did not happen. When I put it back into my rack, first powerup, and... NO 12V!  
Although if I gave it enough time (2 seconds) the 78L12 would eventually start...

After some powerups the 2s delay was getting bigger and bigger. I had to wait 20 seconds before the led turned on (when the whole thing happened). After some time, I was back at square one. It would either start immediately or hang.
Seems to happen almost always when "cold-booting" ( = enough time has passed from last power-off and caps have emptied or something), If I don't give it enough time, and powerup with a 1-2 second delay from poweroff it will always come to life right away...

Should I change my caps back to 1000uF? I don't know what causes such problem, since the 7815 and the 15V rail has no problems at all.
Everything is working perfectly except this! ANNOYING!!  

EDIT:
DISCOVERY:
------------

Ate something for lunch, came back to my gssl, switched it on and off, like, a fabajillion times, and it always worked, left it some time on, then switched it off and back on, no 12V...

I discovered that if I bypass/unbypass the compressor 7-8 times, the 12V will eventually appear as soom as I set the bypass in (no compression) for the "n"th time - never happens in the "compression in" setting.

Also seems to happen more often if there is audio at the input (coincidence?)
I'm saying this because after trying different stuff until my fingers hurt from switching I concluded that the only sure way to power it up properly is with no audio at the input, bypassed compression circuit and the 78L12 will start sooner or later. Go figure  :

 

[oilcanstudios]

if i want compression on all the time can I just jump the on off on the control panel?

 

[Alain]

Hi evereybody,

I still have some problems with my ssl clone

1 - When I power it I get a big pop in my loudspeakers
should I need to install a relay or some soft opening device??

2 - I have the (that2181 LA)vca
should I leave in place the trimpot?

3_ I also have (but not install yet) the turbo part
but the vca is 2180 LB is this ok or I need to put the same 2181 LA?

4- I still have some ground noise should I take out the wire 0 on the input and output
and leave only the ground from the power (AC)?

5- When I touch anywhere on the pcb the sounds goes off and on
in fact when the sound is back , after few seconds it goes back to a noise
up to when I touch it back (pretty sensitive , almost like my girl friend!!)

thank you.

 

[Harpo]

Ate something for lunch, came back to my gssl, switched it on and off, like, a fabajillion times, and it always worked..

Hi Stefanos,
missed your edits as these don't show up as unread posts.
Sounds like a plan. If it doesn't start, switch it off, have lunch and try again later.  ;D
When you search for "latch-up", you might stumble upon this topic http://www.groupdiy.com/index.php?topic=440.0
Easiest approach as seems is to use a different brand of this regulator. Never had this problem myself.
The previous diode fix against potential latch-up problems was also recommended by STMicroelectronics, unfortunatly without constant success for your brand of regulator.

 

[ytsestef]

Now with normal usage it doesn't happen. Normal Usage = No more than 5 powerups per minute unless cooled down for 10 minutes. This means I can get the unit to successfully powerup 5 times consecutively, after tha 6th powerup chances are the problem will appear at a rate of 1 out of 2 times. However, let it cool down for 10 minutes at least and then the first 5 powerups are a guaranteed success!

In other words, much improved, still there. I'm fine with it, but since I will order my SSL9K tomorrow from farnell, I thought I might get some 78L12s while I'm at it. Any guaranteed/tested brands for the GSSL??

Thanks a lot Harpo (and everyone else)

 

[warpie]

I used panasonic on mine and never had a problem. Not sure if farnell stock them. They should do tho...

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=UK&keywords=an78l12-nd&x=0&y=0

 

[regularjohn]

Hi evereybody,
I still have some problems with my ssl clone
1 - When I power it I get a big pop in my loudspeakers
should I need to install a relay or some soft opening device??
2 - I have the (that2181 LA)vca
should I leave in place the trimpot?
3_ I also have (but not install yet) the turbo part
but the vca is 2180 LB is this ok or I need to put the same 2181 LA?
4- I still have some ground noise should I take out the wire 0 on the input and output
and leave only the ground from the power (AC)?
5- When I touch anywhere on the pcb the sounds goes off and on
in fact when the sound is back , after few seconds it goes back to a noise
up to when I touch it back (pretty sensitive , almost like my girl friend!!)
thank you.

1. Why are you turning on gear with your speakers on?  Speakers should always be the LAST thing turned on. I don't know of anything that doesn't make that noise when you turn it on with live speakers.
2. The 2181 must have a trimpot to work.
3. You should have the same VCA in the turbo as you do in your sidechain.  You can actually save some money and use the 2181C in the sidechain, because the audio does not pass through the sidechain.  You're just using the sidechain to generate control voltages for the audio path VCA's, so the 2181C's THD specs don't really matter here.  Definately use the 2181A for the audio though.
4. Only the ground from the input should connect to chassis ground.  The ground from the output should remain "floating".  If you still have an issue, then disconnect the input audio ground.
5. Why are you touching the pcb when the unit is powered on?

 

[Alain]

1. Why are you turning on gear with your speakers on?  Speakers should always be the LAST thing turned on. I don't know of anything that doesn't make that noise when you turn it on with live speakers.
2. The 2181 must have a trimpot to work.
3. You should have the same VCA in the turbo as you do in your sidechain.  You can actually save some money and use the 2181C in the sidechain, because the audio does not pass through the sidechain.  You're just using the sidechain to generate control voltages for the audio path VCA's, so the 2181C's THD specs don't really matter here.  Definately use the 2181A for the audio though.
4. Only the ground from the input should connect to chassis ground.  The ground from the output should remain "floating".  If you still have an issue, then disconnect the input audio ground.
5. Why are you touching the pcb when the unit is powered on?

[/quote]

Hi and thank you  Regularjohn

yes I was touching the pcb when powered on!

but also I dont get any compression , any or very small makeup gain,
in fact it look like if no controls are working,
when I solderd the ratio attack release switches I put thems on the pcb
and I put a lot of attention to put it in the right position, so I dont understand why it's
not working.

I chek all the sorders points and everything seem clean (no cold , or bad solders point)
so could the pcb be crack ?
therefore I am thinking now to get a new pcb and redo the hole process( ??? :'(

thank you
Alain.

 

[audiophreak]

Hi All,
 Sorry to but in...

    I am having a problem and have tried desperately to solve it myself, but alas I have run out of ideas... :'(

 - I purchased two Gssl sets with SSC, ordered parts, started building, then found the thread on the Turbo board, so to utilize what I had already purchased, I ordered one more GSSL main PCB and three turbo boards, one for an Ultimate GSSL with SSC and SSC with Turbo, and then two GSSL  with turbo... ;D

    The 1u case I started I am using as a test bed for the other PCBs, so in testing, it is the same control PCB, gain and threshold pots, power trans and connectors ect... just changing out the main PCBs.

    ... Main PCB #2 works fine, passes audio, compression works, makeup gain and all  BUT... the audio is slightly distorted.. :'(

    ....  Main PCB #3   passes audio, same slightly distorted audio as PCB #2, BUT.. when the meter indicates gain reduction, the audio cuts out, raise the threshold so you dont go into gain reduction and the audio comes back, although still slightly distorted... :'(

     I have checked all solder pads with magnifying glass and meter and have replaced all the opamps and VCAs, no change   :'(



   I swapped out all the    PCBs and metered all the pins -

 PCB #1 works fine and as it should and sounds awesome !

 PCB #2 has some differences pin#1 on 072 reads +2.283vdc and on PCB#1 its +0.758vdc
                                         pin#7 on 072 reads -0.004vdc and on PCB#1 its -0.154vdc

 PCB #3 has pin#1 on 072 reads +3.114vdc
                 pin#7 on 072 reads  -1.710vdc

  ... all other meter reading look O.K.

 ... any thoughts.... anyone ?...    

 Thanks,
          Chip

Edit - I also removed both left and right VCAs and jumpered pins 1 and 8 , audio passes and is clean, when changing threshold, meter indicated gain reduction, but none is heard,  also I read in a post that pin #1  on the 072 varies with threshold setting and I verified this on PCB #2 and #3 form 0.003 to 3.090vdc

Edit  Edit : also, this slight distortion does not change with attack/release settings and is also present when switched to Bypass

  ...anyone ?
   

 

[Alain]

Hi ,

I Am proud because I finally coul make
My gssl work, it is not perfect yet
but improving
so the problem now is the ground noise
how to get rid of it,
I took out the gr on the output
I took out the gr on the input
an then put out the gr on the ac, and still have noise.
could it be  come from semiconductors?


Thank you

 

[SWAN808]

Im tentatively looking into building a GSSL and have a few preliminary questions if anyone can help...

What are the basic tools needed? Im thinking of buying one of the pre drilled cases in the white market as I dont want to do the heavy work.

Ive noticed there are resistor changes needed depending on which THAT chip you use - are there any standard deviations from the PCB I need to know about?

What is the most preferable THAT chip? Given I would like some colour if poss...

Is there a components supplier in the UK which stocks all the components? Can you just send them a components list and have them put the order together? (lazY!)
I have been on the RS website but it seems like you need to buy many more parts than needed and my basket started to get quite expensive quickly...do most people do this and build more than 1 unit?

What is the rough GBP cost of the GSSL parts (using a behringer meter and 60GBP case)

Finally - is it just a case of getting the components, PCBs and case - and using the Gyraf page and this thread as guidance? Or are there some other official step by step instructions I dont know of?

Quite a few Qs from a turbo noob - thanks

 

[Harpo]

so the problem now is the ground noise
how to get rid of it,
I took out the gr on the output
I took out the gr on the input
an then put out the gr on the ac, and still have noise.
could it be  come from semiconductors?

Hi Alain,

what kind of noise or more likely hum is your problem ? If it is humming, at what frequency (50/60Hz or 100/120Hz) ?
Whatever 'gr' might be, probably meaning a XLR-pin1 connection to 0V on pcb or to case/safety ground, a pic of your build might help to narrow it down if this could be caused by a ground loop, mains transformer induced hum, wire placement, ...

 

[larswinther]

I've just finished a GSSL and I have a problem with the power:

Everytime I turn on the machine the fuse blows. I can plug in the power and measure 220v (EU) through the fuse and all, but the second I turn on the power (on the machine i.e.) the fuse blows. Any idea where I should look for the error?
I've already build one GSSL before, which works perfectly, so I just copy-pasted the wiring from that. I've also had a thorough look on the PCB and I can't see where the problem should be.

Anyone?


brgds,

Lars

 

[audiophreak]

  ... no takers ? .... O.K..    moving along...  can the sidechain VCA be bypassed, ( jump pins 1 and 8 ) same as the Left and Right VCAs  ? 



 

 

[Alain]

what kind of noise or more likely hum is your problem ? If it is humming, at what frequency (50/60Hz or 100/120Hz) ?
Whatever 'gr' might be, probably meaning a XLR-pin1 connection to 0V on pcb or to case/safety ground, a pic of your build might help to narrow it down if this could be caused by a ground loop, mains transformer induced hum, wire placement, ...
[/quote]

Hi Harpo thank you for helpping beginner again.

so I finally ca use my gssl comp, BUT
some problems still need to be fied.

1 The ground noise (or the noise let say) sound like ground + high frequencies
not a complete white noise , no mid in this

2 When I use the release at 6 the sound is totally distorted

3- The ratio position 2 is compression more than position 4 !

4 Where should I take current for the light in the meter?

thank you a lot

Alain.

 

[Harpo]

1 The ground noise (or the noise let say) sound like ground + high frequencies
not a complete white noise , no mid in this

Hum might come from ground loops. Make sure, there is -if any- only one connection between 0V and your case. (metal stand-offs for pcb mounting might need isolation washers).
Hum might come from mains transformer. Losen the fastening screw and turn it this way, that sensitive areas of the circuit, most often input, are least exposed to transformer radiation (for usual highest toroid radiation is where secondary wires leave the transformer). Tightly twisting your AC leads (primary side and secondary side) should  help further.
Hiss might come from wrong component values or broken parts.

2 When I use the release at 6 the sound is totally distorted
3- The ratio position 2 is compression more than position 4 !

Annoying, isn't it  ;D ...
Have a look at the schematic and count the step positions  .
Turn off the fastening screw from your lorlin switch.
Remove the end stop washer.
Turn the switch full ccw.
Now place the end stop washer back to pos.5 for release or to pos.3 for ratio.

4 Where should I take current for the light in the meter?

Depends on the light in your meter (light bulb/fastoon lamp or LED?) Lots of answers by other members. My last 3 answers to this question in this thread on pg.157,165,167. The search button is not that far away.

 

[loicmoreau]

hi everybody
i finished my gssl and i have a really wierd problem .
when i power up my gssl there's no sound untill i make a short between pin 6-7 on the that2181c of the left vca .
i noticed that while scratching between solder points on my board with a screwdriver.
it makes a little spark (probably not that good i guess) and after that everything work normally (comp sound nice on both channels, meter, knobs, bypass, power on led, everything work as expected)
it's a gssl without any mods
if anybody have any idea i would be very greatfull
thanks in advance