Calibrating the GSSL (with That 2180's installed and Turbo-OnBoard)

Hi,

with the installation of the Turbo Board i've finally finished my GSSL-Gear but i'm not sure if the thing is working correct so i want to calibrate it.

Does the following procedure therefore make sense:

1. I generate a 0 db Signal with the signal generator of wavelab and inject this into the Inputs of the GSSL.
2. i connect the outputs of the gssl to the inputs of my Audio-Interface.
3. i switch the compressor off and readjust the input level of the audio-interface until i get 0 db input level (so i can be sure that the Signal is passing thru without gain reduction related to the input level).
4. i turn the treshold to 12 o'clock position (0db) and swicth the compressor on --> Now there should be no gain reduction. when i slighly turn the Treshold counterclockwise the compression should start.
If the compression starts already at 12 o clock or later (e.g. one o'clock), i have to put an Resistor at the + leg of the Threshold Poti. If the compressor compresses to late (e.g. in 11 o clock position) i have to put an resistor at the - leg of the Threshold Poti.

So far correct?

And then i would repeat the procedure at fully Counterclockwise position (with -20db Signal?).
Also correct?

But i have read also about guys who changed other resistors too (the 47k's at Sidechain input with 120 k's, and so on), so can anybody tell me the whole way to get the thing doing what it should do?

Cause i have also the suggestion that the Ratio is not working correct...

Every help is appreciated.
Jakob, are you here ;-)?

Greetz

Daniel

I have exactly the same questions!

can someone help us?

Hallo Daniel,

For the Gain-Settings:

If you set 0dB fs in Wavelab, I guess your Interface gives out far more than the Studio-Standard of +4dBu. You should measure the real output.
I'm not sure how the GSSL-Threshold-point ist calibrated, but I guess that the 0dB relates to +4dBu. So you should pull the Wavelab-Fader down to have that gain at the output.
My guess.

Chris

Set your input signal to +4dBU (~1,23V), bypass the compressor, you should read the same at the output. AFAIR the two 27k (printed 15k on the PCB) are responsible for the unity gain. 0 dbFS on your sound card generates some 15-20 dBU which is >5V. That's not a common studio reference level.

(I will delete this if I'm dead wrong ;-))

HELLO
"basementmedia"
have you used the 2180 trimless vca on your gssl?
if yes ,
have you removed the 2 -47k resistor
as indicated here?
http://diy.fischerworks.com/diy_pictures/ssl_overlay_web.png

thanks