GSSL HELP THREAD!!!

[mathflan]

ok

The noise is not cause by the toroid transformer, I move it but stil have noise.

In fact I'am wondering if it's not cause by the SSL highpass filter from Greg.

I put the Ground of the JAck, send , return to the star ground and did the same to the ground of the SSL high pass filter.

I'am wondering too if I have to use Shielded cable for the Relay board


Hey DAX, you 're not from audiofanzine??

 

[khstudio]

Greg,
Thanks for responding :thumb:

After HOURS :evil: of troubleshooting I found it has nothing to do with the main circuit board... it's the control panel. I still don't know what but I'll find it. I didn't look there because it had been working fine & I didn't do any work there or even remove it... BUT, not that it's a big deal, I found that the unit with the 218x VCA's has a negative voltage everywhere from the output electro cap right after the 1st 5534's thru the 15/27k resistors, thru the summing resistors up to the sidechain VCA & the one with the 2151's has a POSitive voltage in those spots. When I was poking aroud trying to find why the Threashold was way off I noticed this & thought it was a problem but it ends up that it's NOT :shock: I finally pluged the board into the working (corectly) units front panel & it kicked ass :green: .

So, the voltage difference sidetracked me & must be ok. It was the front control board the whole time.

I still would like to see if anyone else is getting a positive or negative DC voltage in those area's. It could be the different VCA's or the distortion trim circuit being there or not... who knows.

I think my new quote will be "Solid state ain't easy to troubleshoot"

 

[Bluzzi]

Just a question here. I know that the Sidechain is just a high pass filter to affect the way the compressor behaves but what does the TRUST mod do?

Jim

 

[gyraf]

..the same, just a softer (3dB/Oct) filter..

 

[AudioguyII]

So excited I finally finished my first SSL.... (please excuse my newbieness)
When I test voltage I get 9.4V instead of 15 V.
Any ideas why?
I'm using the MT2086 from Jaycar. Wired with yellow on Pin 1, red- pin 2, white Pin 3, and Purple Pin 4.
What other test sould I perform before inserting VCAs and likes?

Thank you!!!

Excited Newbie.

 

[mathflan]

Audioguy what voltage do you have at the output of your transformer??

with Alternative voltage scale on multimeter...

 

[mathflan]

I Post a thread "SSL comp noise due to The Bypass LED switch"

I put the diagram here, (better place ) of my Mounting of the SSL.

I have a noise ( 100Hz or 200Hz ) when I put the Makeup at MAX, When I put a 0Db signal, the noise is at very low volume but I'm afraid that when I will use my SSL on big system,, the noise will become listenable.

I'd like to know If I made something wrong,:roll:

Thanks if you can take time to watch this :

 

[5meo-geo]

Audioguy where did u connected it???

check for shorts
and also check id 7812 and 7815 connected right way

i had simular problem with negative voltages
7912 was connected wrong way

 

[AudioguyII]

Hey Guys,
Thank you so much for getting back to me...
This has been driving me crazy.
The transformer is from Jaycar MT2086 .
Tried connecting to both locations on PCB. now it's at the corner/"external transformer" spot.
I connected the yellow and white together to form center tap (these are the "0" wires) then purple and red go to the extremetie of the connector.
I get a reading of 8.47V from testing yellow/white (connected together) and purple .
and a reading of 8.47V from yellow/white(connected together) and red.

My 78L12 and 79L12 seem correct. Flat part facing in.
I have not installed VCAs or connecteted XLRs, or ground.

I've checked soldering and it lloks good. Haven't gone through to verify if components are all a right location but I did check and recheck as I stuffed the board.

Of course this all happens when I need this SSL to do a mix with a looming deadline..... please help me save $$$ and not have to go buy a stereo comp!!!!

Thanks guys!

AudioguyII

 

[smallbutfine]

mathflan, what is your opinion about the star point you are using? I would, if i were you, i would take a thick piece of green-yellow covered copper cable and strap the grounds together at the point on the left of the IEC plug and not at pin 1 of the first XLR in. strange (in my opinion) is that you didn't ground the key in directly to chassis like the xlr's, but to pin 1 of the first XLR. This is not making sense to me at all but maybe i'm just blocked at the moment...

I've not looked too long on your diagram, so maybe i overlooked something someone else will find...

If you just want to find out, if the grounding scheme is the source of noise or the relay boards, i would simply groundlift (only) the in's completely for troubleshooting and listen again. Is the noise/hum still remaining? what relais are you using?

Kind regards and successful troubleshooting :thumb:

Martin

 

[mathflan]

HI smallbutfine, Thanks for the answer.

In fact the KEy input I use is a JACK connection with plastic lug so I have to connect the Pin 1 of this JACK to the star grounding.

In fact my problem is that My XLR are connected to the chassis by themselves when I screw them.
Perhaps I have to Put some scotch around XLR LUG so as to BE not connected to the chassis.
By doing that, I could Connected the Chassis of the XLR at only ONE point.

I Tried a lot of thing to See where the noise come from, But I don't have disconnect the Relay board, I'll try...

I use MT2 AXICOM, TYCO

 

[BladeSG]

[quote author="AudioguyII"]Hey Guys,
Thank you so much for getting back to me...
This has been driving me crazy.
The transformer is from Jaycar MT2086 .
Tried connecting to both locations on PCB. now it's at the corner/"external transformer" spot.
I connected the yellow and white together to form center tap (these are the "0" wires) then purple and red go to the extremetie of the connector.
I get a reading of 8.47V from testing yellow/white (connected together) and purple .
and a reading of 8.47V from yellow/white(connected together) and red.

[/quote]

I had this wrong when I first built my first GSSL. I have the same jaycar toroid.

I've got it wire:

red/white tied together for - 0V (middle)
purple - 15V (outside pin)
yellow - 15V (outside pin)

This should work.

 

[BladeSG]

Now I'll ask my own question....

On the gssl pcb it's marked (in the area for pcb mounted toroid) that a 4.5VA toroid will do.

I've got the above mentioned MT2086 toroid which is a 15v-0-15v 20VA. Is it safe for me to assume that if the gssl only requires 4.5VA I'll be able to power 2 gssl's with this one toroid?

Also how might I go about calculating if a PSU pcb (in this case Keith's SSL 9K PSU pcb (thanks Neeno for the idea)) will handle 2 gssl's?

Thanks in advance

Steve

 

[AudioguyII]

Thanks BladeSG,

I also realize I just made a huge error. I live in NY , USA 120V . Not 240V input. I thought this transformer was able to handle all input. So I think I'm only getting half due to this.
I connected it in series and got 16.5V output.... so..... After thinking about it ... I have a few of these transformers. So I took two... I connected their respective red and white together , connected the 2 yellow togther from the two, which leaves me with 2 purple at 16.5V.
I connected the 2 yellow to center tap and the two purples to the live extremities. I finally got 14.9V and -14.9V on my 15V rails, but I get -20V on my 12V rail, and now my LED doesn't light up. It did before when I got 10V on the 12 V rail.
What am I doing wrong....
I've searched the thread but can't find my solution...
Please help.

AudioguyII

 

[AudioguyII]

Sorry, 12 V rail is measuring 21.7V to ) pin on the input XLR

 

[ioaudio]

i got a gssl from a friend, he couldnt make it work. i found 7 solder bridges and some resistors with the wrong value.

fixed it, powered it up but no work.
i read +0,6 volt on the positive +15Volt rail and -9,79 on the negative -15 rail. couldnt find any further solder bridges, ac on secondary of the trafo is ok.
are the regulators gone?

any help appreciated,
max

edit: just found out that the original trafo, which supposed to have 2x18 volt, gave me 28 volt AC unloaded. did this fry the regulators?

 

[Greg]

Actually the power trafo on the GSSL is 15-0-15, not 18-0-18. If you're getting 28-0-28 you'd be dissapating alot of heat and the regulators might be toast, so a regulator swap is not be a bad idea. Are the regulators measuring a short or open circuit?

@Audioguy, I'd recommend getting the correct power tranny for 110/120 before proceeding.

 

[Eurocide]

[quote author="BladeSG"][quote author="AudioguyII"]Hey Guys,
Thank you so much for getting back to me...
This has been driving me crazy.
The transformer is from Jaycar MT2086 .
Tried connecting to both locations on PCB. now it's at the corner/"external transformer" spot.
I connected the yellow and white together to form center tap (these are the "0" wires) then purple and red go to the extremetie of the connector.
I get a reading of 8.47V from testing yellow/white (connected together) and purple .
and a reading of 8.47V from yellow/white(connected together) and red.

[/quote]

I had this wrong when I first built my first GSSL. I have the same jaycar toroid.

I've got it wire:

red/white tied together for - 0V (middle)
purple - 15V (outside pin)
yellow - 15V (outside pin)

This should work.[/quote]
what a funny coincident. It was my main error, too! Now all voltages are fine! Learning by doing
I've found the solution on page 40 of this thread.

 

[ioaudio]

thanks greg !
already replaced the transformer with 2x15v. the regulators do not measure a short, nor do the voltage lines.
its much more difficult to trace something you didnt build yourself...

edit: found out that the voltages are ok when i lift the -15v wire bridge next to the two 47k resistors. resistance to ground is 800R at that point.

 

[AudioguyII]

Hey Greg,
Thanks, I wish I could find a place that has them in stock... if you know of somewhere, I'd appreciate it. Digikey is out.
So using two wouldn't do the trick?