GSSL HELP THREAD!!!

[pearldrum944]

I'm using the the 2180LA VCA's do I need to mount the 2 47k resistors next to the left VCA, I have checked various pages and a question mark remains next to this point.
Also my compressor is passing audio and the make up is working, it appears no compression s being applied when the bypass is in or out.
Any help would be greatly appreciated.
Thanks

I used 2180LB and left them in.  Also, did you add the jumper next to the meter connection (above the wire connections) on the control board?

 

[radiance]

I'm using the the 2180LA VCA's do I need to mount the 2 47k resistors next to the left VCA, I have checked various pages and a question mark remains next to this point.
Also my compressor is passing audio and the make up is working, it appears no compression s being applied when the bypass is in or out.
Any help would be greatly appreciated.
Thanks

Without these two 47K resistors you're not feeding any signal into the side chain...check the schematic and you'll know what I'm talking about.

 

[Harpo]

I'm using the the 2180LA VCA's do I need to mount the 2 47k resistors next to the left VCA, I have checked various pages and a question mark remains next to this point.
Also my compressor is passing audio and the make up is working, it appears no compression s being applied when the bypass is in or out.
Any help would be greatly appreciated.
Thanks

The 127K resistor (your rightmost red dot) seems also missing. This way only makeup is working, but the control voltage coming from the sidechain is left out.

 

[Autophase]

I'm using the the 2180LA VCA's do I need to mount the 2 47k resistors next to the left VCA, I have checked various pages and a question mark remains next to this point.
Also my compressor is passing audio and the make up is working, it appears no compression s being applied when the bypass is in or out.
Any help would be greatly appreciated.
Thanks

I used 2180LB and left them in.  Also, did you add the jumper next to the meter connection (above the wire connections) on the control board?

Yes I have jumpered this, should i have done that?

 

[Autophase]

I'm using the the 2180LA VCA's do I need to mount the 2 47k resistors next to the left VCA, I have checked various pages and a question mark remains next to this point.
Also my compressor is passing audio and the make up is working, it appears no compression s being applied when the bypass is in or out.
Any help would be greatly appreciated.
Thanks

The 127K resistor (your rightmost red dot) seems also missing. This way only makeup is working, but the control voltage coming from the sidechain is left out.

I put a 120k resistor in here, I'll put in the 2 47k resistors as radiance suggested
Cheers for all the advice guys, watch this space.

 

[peteys]

Can anyone tell me where I could get power for the led in the Behringer meter?

I'm already using the power on led on the daughterboard for the power indicator.  Could I use that spot to power both led's?  I'm using Greg's led from his BOM for the power indicator.

Also,  anybody know where I could get a nicer led for power than the one in Greg's BOM.  I really would like something like the one that comes with the Universal Audio 2192.  That's a nice light.

 

[jrfred453]

I read that you shouldn't tie the power led and meter led together because the gssl uses the 12v for reference.
I have no power on led. Is it ok to connect the meter led here instead? Does this connection need a voltage dropping resistor to get to 3v?
Also what resistor should be used in order to make Ptown's meter read properly? I've read a bunch of different answers ie 12k, 4.7k, and 1.2k.
It looks like I jumpered the 2k resistor on the main board already.
I'm using dbx 202 vcas if that makes a difference.

 

[livingnote]

@pearldrum - right, your levels are fine. Funny bug. Of course that can only mean something
in the SC isn't right, but I don't have the numbers in front of me - difficult to know what to ask
next, have you looked in the meta?

@LEDs (my favorite) - The problem is the 78/79L12 regs - they're flimsy. This is not a problem
for running small audio circuits like the sidechain, but as soon as you start hanging christmas
lights on them they can't supply enough electrons and your sidechain starves. Hook LEDs up
to the out pin of the big 7815 and you're fine, adjust LED resistor to fit your personal idea of
brightness.

Oh and calculating LED resistor: [(Supply voltage) – (LED forward voltage)] / (LED current)

If the LED is said to have 2V 20mA and your supply is 15V then you just insert like

(15V-2V)/0.02A = 13/0.02 = 650Ω.  (Ohm's Law)

 

[regularjohn]

Also,  anybody know where I could get a nicer led for power than the one in Greg's BOM.  I really would like something like the one that comes with the Universal Audio 2192.  That's a nice light.

Do a search for "jewel light".  
Most of them are T2 or T3 mini incandescents that require AC power though.
When I've used them, I pull their power directly off the power trafo secondary and drop the voltage (if I need to) with a big 2W resistor.
The voltage doesn't have to match, just make sure you're not feeding it more than it's rated for.  You can actually lessen the brightness by feeding it lower voltage.

 

[SWAN808]

Is this normal behaviour for a GSSL?

- Output very hot - input must be low in order not to clip my converters on way back in. Consequentially - threshold knob is often at highest amount (turned all the way on)...

is this the 'unity gain' calibration that may not have been done? http://homepage.mac.com/marten.thielges/gssl/calibration.html

I have got a large General Electric 1mA meter.

- do I need to know the 'full scale deflection' of my specific meter? In some calibration instructions it says you can simply apply a 10k resistor for -10db reading...at the moment I have no way of telling how much the meter shows as being GR...apart from calculating levels in and out...

Im noticing another issue with the meter - it 'seems' to be erratic. On the same settings sometimes showing large GR sometimes minimal GR - anybody seen this type of thing before?

 

[SWAN808]

Meter example:

It seems to interact when I change the Steffen sidechain values...I switch to HPF 60 - I get a reading of 8 on the meter. I switch back up each HPF -then I switch back down to 60hz - it now shows 3 on the meter...whilst all same settings and same material...

 

[Autophase]

hey guys, I cant seem to get my GSSL working right.
The make up is working perfectly, the bypass defeats the make up correctly, the main problem is i seem to have no compression at all.

Any suggestions?

 

[regularjohn]

Meter example:

It seems to interact when I change the Steffen sidechain values...I switch to HPF 60 - I get a reading of 8 on the meter. I switch back up each HPF -then I switch back down to 60hz - it now shows 3 on the meter...whilst all same settings and same material...

Definately something wrong there.  Hard to say without seeing the pcb.

BTW, the easiest way to calibrate the meter is to use a 5K trimpot in place of the 2K meter resistor.
Then you have to run the output of your gssl into something that's got meters (I use my 2 track Otari MTR10).  Run a 1.23V (+4dB) 1K sine wave into the gssl while it's in bypass, and make sure the meters on the post-gssl device are at 0VU, then take the gssl out of bypass.  Turn the threshold knob and see if the decrease in output level (shown on the 2 track's meters) matches your gssl's gain reduction metering.  Adjust the 5K trimpot until they match.  

The GR amount will change with different sidechain high pass settings and at different attack and release settings.  It should remain relatively even between ratio settings though.  

Also, to perfectly calibrate the ratio, use a 200K trimpot in place of the 127K ratio resistor.

You can also perfectly calibrate unity gain by using 20K trimpots in place of the 15K resistors just before the output opamps.
See pic (this one's got independantly switchable output transformers!):

 

[bpucekov]

whether the 25V voltage is too low for the 22uF Elcos in gssl, schema says 35V I ask because I have about 200 pieces of 22uF 25V and wanted to use them
bpucekov
www.akaj.hr

 

[livingnote]

AFAIK that shouldn't be too much of a problem because your
signal is rarely if ever that high - currents also are very low
comparatively. Correct me anybody if I'm wrong.

 

[bpucekov]

thanks
sorry stupid me
my elcos is 22uF/16V
is this ok?
bpucekov
www.akaj.hr

 

[radiance]

thanks
sorry stupid me
my elcos is 22uF/16V
is this ok?
bpucekov
www.akaj.hr

22uF/16V would be fine in the audio path I think....but....
....what voltage is a normalized modern level signal? I don't have the math ready here. I could do search , do the math ...but I'm lazy. Line levels can't be 16V right?

EDIT: while thinking about this I do think 16V is to low since the +15  -15V which powers the NE5532/4's allows for aprox 21V output signal swing...

 

[bpucekov]

thanks
sorry stupid me
my elcos is 22uF/16V
is this ok?
bpucekov
www.akaj.hr

22uF/16V would be fine in the audio path I think....but....
....what voltage is a normalized modern level signal? I don't have the math ready here. I could do search , do the math ...but I'm lazy. Line levels can't be 16V right?

I hope so

 

[Harpo]

at least in front of your 78L12/79L12 they need a higher rating than your 16V parts.

 

[bpucekov]

thanks