GSSL HELP THREAD!!!

[Autophase]

Hi,
I've seen a 1Ma center zero meter.
How hard would it bue to use this and have a switch, so it will show GR in the negative and output on the positive?

 

[mac]

Easy with something like this....

http://www.expataudio.com/expatshop/index.php?act=viewProd&productId=7

Mac

 

[livingnote]

Hey Casio, you might want to try to take it from the top. If your voltages are correct,
see if you can get yourself a probe to go looking for the signal in the individual nodes.

You grab this ol' meter probe and solder it to the hot (xlr pin 2) pin of an XLR and 3 to 1
to ground. Or a simple mono jack plug - stick that into your DAC and monitor to headphones.
Now you can go looking for the signal and where it's not getting through. Cross out
nodes where the signal gets through ok on the schematic and work your way forward.

I know, it sucks when it totally doesn't work, but with your power headphones on you
pretty much always get through...though sometimes the circuit board doesn't have much
appreciation for you left by the time you're done

 

[regularjohn]

Easy with something like this....

http://www.expataudio.com/expatshop/index.php?act=viewProd&productId=7

Mac

That pcb is for use with VU meters which read AC signals, not for DC 1mA meters. 
It wouldn't work to do what Autophase was asking.

 

[peteys]

Just wondering if I need a resistor if I'm using the Power On Led in Gregs BOM,  67-1155-nd, connecting it to the daugherboard Power on contacts?  Also I assume I need a DPDT Power switch to turn power and Led on together or would that be a SPDT?  I'm not sure.  I was wondering how many amps the switch should be and what configuration.  Would it need to be a On-none-On config?  I want to use a toggle.  This switch stuff is a little confusing. 

 

[livingnote]

Ah - where exactly do you want your LED?

 

[Biasrocks]

Just wondering if I need a resistor if I'm using the Power On Led in Gregs BOM,  67-1155-nd, connecting it to the daugherboard Power on contacts?  Also I assume I need a DPDT Power switch to turn power and Led on together or would that be a SPDT?  I'm not sure.  I was wondering how many amps the switch should be and what configuration.  Would it need to be a On-none-On config?  I want to use a toggle.  This switch stuff is a little confusing. 

Just finished building mine.

No resistor needed if your hanging a LED off the control board, power is provided by the control board.

Power switch should be rated for 3A or more iirc.

I use SPST switches for power in my builds, switching the hot side of the power connector before the transformer.

There was a thread recently discussing using DPDT switches to switch Neutral at the same time, personally I think it's overkill but if you want to be totally sure there's no voltages present that's the way to go.

http://www.groupdiy.com/index.php?topic=8016.0

Mark

 

[peteys]

The led I want to use is for the power switch.  So I don't need a dpdt for the power switch if I want to have the led on when I power up?  So when I power up with a spst toggle power switch, I assume the led will just light up?  I was going to wire like you said, just to the hot side of the tranny.

As far as the amp rating, I only ask because Gregs Bom power switch is only rated at 150ma.  I'm don't want to use a rotary but I thought that was way too low for the power switch.

 

[Biasrocks]

The led I want to use is for the power switch.  So I don't need a dpdt for the power switch if I want to had the led on when I power up?  So when I power up with a spst toggle power switch, I assume the led will just light up?  I was going to wire like you said, just to the hot side of the tranny.

Right, the control board provides the regulated power and dropping resistor for the LED.

As far as the amp rating, I only ask because Gregs Bom power switch is only rated at 150ma.  I'm don't want to use a rotary but I thought that was way too low for the power switch.

150ma seems low for a power switch.

I checked and the toggles I'm using are rated at 3A 250vac, 6A 125vac.

Mark

 

[pearldrum944]

This thread is an amazing wealth of knowledge and is certainly the reason I have gotten as far as I have...unfortunately I am stuck.
I finished my gssl today (except for hooking up the meter) and tried passing audio.  I have good rail voltages, all very close to their target.

I am getting huge output levels and distortion most of the time.  I am using THAT2180's and followed Matt Fischer's instructions of removing the 50k trimmers, 1M's, both 10k's, the 68R's, changed the 3k9 to 5k1, and the 100k to 127k.

At first I mounted the VCAs with the 4th pin in place, after I bent it to the side I was getting more of the tone or track I was playing through the compressor, but a LOT higher output level.  I realize this has been covered 1,000 times before...but I am correct in leaving the 4th pin out of the circuit right?  (EDIT: I guess with the resistors out pin 4 makes no difference, I must have thought it changed because between powering the compressor up and down the output changed from low to high)

Sometimes the compressor is fairly quiet and will play the track (still distorted), other times it has 0dbfs noise and hum coming from it...even without an input.  Bypass seems to make no difference, and make-up gain only does occasionally.  If the compressor is acting a little better and playing at half-way reasonable levels, it seems that if I even touch the make-up gain pot the output skyrockets.  Here is a signal trace I ran with a 0dbfs tone running

5534: pin 2: 3.2v
        pin 3: 3.1v
        pin 6: 13.9v

27k resistor before VCA:13.7v on first end, .5v on the other  (is this right?)

VCA input: .5v

VCA output .1v   (but -2.5 DC?)

5532 pin 6: .1 AC, (still -2.5 DC?)
      pins 2,3,5: 0.0v
      pin 1's read: 13.8v, and 14.9v
      pin 7's read: 13.9v, and 15.1v

 

[radiance]

pearldrum...remove both VCA's (not the side chain VCA) and jumper pin 1 with pin 8. This way you can check the input and output stages. Audio should pass some were around  unity gain depending on what resistor is in front of the VCA (dunno exactly).

 

[Harpo]

5534: pin 2: 3.2v
        pin 3: 3.1v
        pin 6: 13.9v

27k resistor before VCA:13.7v on first end,

Op amp is either running open loop or at a too high gain setting, caused by wrong part values. Double check for broken traces, check if the op amp is in its socket with all its pins (especialy pin2 not bent inwards) and check the 22K resistor value in the feedback path between pin 2/6.

.5v on the other  (is this right?)

VCA input: .5v

VCA output .1v   (but -2.5 DC?)

5532 pin 6: .1 AC, (still -2.5 DC?)
      pins 2,3,5: 0.0v
      pin 1's read: 13.8v, and 14.9v
      pin 7's read: 13.9v, and 15.1v

The VCA is not voltage but current in/current out.
5532 output (-sign missing at one pin) is a follow up from previous fault in the 5534 line receiver.
good luck

 

[Autophase]

Crimp pins.... what a PITA.
After soldering the headers on, i struggled to get a secure grip with the crimp pins, so much so I've decided to remove the headers and just solder the wires onto the board.
Maybe I was doing something wrong with the crimp pins, but I'd hardly call them an easy soloution.

 

[regularjohn]

Crimp pins.... what a PITA.
After soldering the headers on, i struggled to get a secure grip with the crimp pins, so much so I've decided to remove the headers and just solder the wires onto the board.
Maybe I was doing something wrong with the crimp pins, but I'd hardly call them an easy soloution.

Yeah, crimp pins are a total PITA!
I prefer using screw terminals.  mouser part #'s 651-1725685 and 651-1725737.
They don't fit on Gustav's boards without some additional drilling, but they fit fine on the boards from Chef at Audio Kitchen.

 

[Autophase]

Crimp pins.... what a PITA.
After soldering the headers on, i struggled to get a secure grip with the crimp pins, so much so I've decided to remove the headers and just solder the wires onto the board.
Maybe I was doing something wrong with the crimp pins, but I'd hardly call them an easy soloution.

Yeah, crimp pins are a total PITA!
I prefer using screw terminals.  mouser part #'s 651-1725685 and 651-1725737.
They don't fit on Gustav's boards without some additional drilling, but they fit fine on the boards from Chef at Audio Kitchen.

Glad to hear a veteran like your self has a hard time with crimps as well john, makes me feel less incompitent.
I would have had a power up last night if it wasnt for the crimps. As soon as I get home tonight I'll be going overkill with the solder sucker and solder wick. Get them wires soldered on, then bang first power up.

 

[pearldrum944]

All of my op-amp pins are seated correctly.  When I put jumpers in place of the R/L VCAs I get clean signal.  There is NO noise.  My right ouput is about 6db or so higher than the left and my overall output is a little higher than the input.  So what does this mean for my VCAs? 

Also, my control board does not appear to be working...(but I will test it later this afternoon when I have more time)

 

[radiance]

All of my op-amp pins are seated correctly.  When I put jumpers in place of the R/L VCAs I get clean signal.  There is NO noise.  My right ouput is about 6db or so higher than the left and my overall output is a little higher than the input.

Input and output stage are OK except for the 6dB. Check your input and output connections. When running the gssl unbalanced you get a 6db drop in level...so start looking at the channel that's -6dB.


 

So what does this mean for my VCAs? 

Well, it means that you've a prolbem some were in the side chain section. Check for solder shorts, wrong value components etc. etc. This would all be very easy to track down with a oscilloscope...

 

[Biasrocks]

Input and output stage are OK except for the 6dB. Check your input and output connections. When running the gssl unbalanced you get a 6db drop in level...so start looking at the channel that's -6dB.

Also check to see if you're getting both sides of the balanced connection from the 5532 opamp. In my case I had a missed solder connection on the (-) side of the signal. Resoldered the opamp pins, done.

Mark

 

[pearldrum944]

Success!  Thanks guys!  I found out I was having an issue with the VCA connections, so I mounted them direct to the PCB.  I was poking around the sidechain tracing a tone.  As soon as I touched the 100K resistor next to the TL072 (between pins 6 and 7) the distortion was gone, touch it again and it was back.  So I touched up the solder point and the distortion is gone.  The controls also work fine (as far as I can tell).  

I still have a lower signal on the left output.  I have only .02v at the - side of the output XLR (all others are ~3.7v).  I checked the 100r resistor on the board, one side says 3.7v, the other .02v.  BUT!  I found out that my wiring for + and - was backwards for the XLRs on the pcb connectors(I originally mixed up input/output connectors).  Once I swapped around the wires in the connectors to the other side, the resistor that before was testing bad, tests fine!  And now the 100r on the other side of the connector is showing a drop from 3.7v to .02v...?  I have continuity from the 100r to the xlr connector.  

 

[drive]

HI,
The compression kicks in to late, I have to turn the threshhold to at list 9 o'clock for the comp to start compressing. What would I need too change for it to start compressing sooner?
I tried to change 47K on the threshhold but that does not seem to do much.