Silvas

My GSSL Variable scale meter board....
« on: October 26, 2008, 02:36:43 PM »
Hello

I´ve had many requests for the variable scale meter board i used with my GSSL compressors :





So, here is it, not the nicest layout, but it worked for me. I´m still learning Eagle...



Component layout here :

http://i523.photobucket.com/albums/w355/audioeng80/VARIABLESCALEMETERCOMPONENTS.jpg

Copper side, ready to print and transfer :

http://i523.photobucket.com/albums/w355/audioeng80/VARIABLESCALEMETERFORHOMEETCHING.jpg

Size is 100x60mm. Led spacing is 10mm

It needs a 3pos rotary switch. I used 10pos 36 degree index with programmable stops grayhills in my GSSL builds.

IIRC, the way i calibrate the board is :

1 - Before i solder the GR calibratin trimmers (20, 10 and 5 dB) i adjust them to the following values : 20dB : 1.05k, 10dB : 3.16k , 5dB : 7.32k. The 4th trimmer, which is used to set the led current , i left it at half of it´s value. I think i used 10k trimmers except the 4th trimmer.

2 - assuming that the GSSL is working, i feed voltages to the board, but measuring current draw with my DMM on the positive rail, and without the TL071 opamp on the socket. Then, i feed a positive voltage to the input pin on LM3914, pin 5. High enough to make all the leds on.  The bar/dot jumper should be in.

3- i adjust the 4th trimmer for 70mA current draw with all leds on.

4- i put the opamp in place. Then i feed the compressor with a 0dBFS tone and i monitor levels on Protools (or your DAW of choice). Threshold should be fully CW and no compression should be happening.

5- I put the meter scale on the 20dB position, and adjust threshold for a measured 20dB GR, bypassing the compressor and checking the levels in DAW. Should be exactly 20dB difference with the compressor working.

6 - Adjust the first trimmer so the last led is barely glowing ! Adjust threshold for a measured 10dB GR on DAW, then check that the meter is reading 10dB, the 5th led.  If not, adjust the trimmer and check again until reading is OK.

7 - repeat the process with trimmers 2 & 3, with the rotary on it´s respective positions, and adjusting the threshold for a 10dB and 5dB gain reduction....

I´ve found this meter is very accurate, specially in the 5dB position (0,5dB accuracy) and i love having all the 3 scales for different tasks. I prefer bar mode, is easier to read, but i left the option for dot mode. Excuse me if the explanation is not so clear, my english isn´t the best.
Camilo Silva F.
Camilo Silva F. Mastering
Chia, Colombia


uncle

My GSSL Variable scale meter board....
« Reply #1 on: October 26, 2008, 03:27:59 PM »
Camilo thanks for sharing this!  :thumb:

cheers!  :sam:  :sam:

Silvas

Re: My GSSL Variable scale meter board....
« Reply #2 on: March 25, 2009, 01:58:54 PM »
has someone else managed to succesfully build this?

please let me know !

Camilo Silva F.
Camilo Silva F. Mastering
Chia, Colombia

livingnote

Re: My GSSL Variable scale meter board....
« Reply #3 on: March 25, 2009, 03:03:31 PM »
Beautiful layout.
Quote from: emrr
F-in' hook some Sh*t up and see if it catches on fire
Living Note Studio

rob_gould

Re: My GSSL Variable scale meter board....
« Reply #4 on: March 25, 2009, 04:07:16 PM »

Hi,

Sorry for the OT, but can you tell me who did / how you did the engraving on your front panel.  Loving your personalised signature engraving!

Cheers,

Rob
Studio furniture, modular synth cases and more...

www.gouldcaseworks.nl

Silvas

Re: My GSSL Variable scale meter board....
« Reply #5 on: March 26, 2009, 06:35:32 AM »
the engraving was my local laser engraving shop....they usually charge me 50 cents/minute and IIRC that panel took 6-7 minutes. scanning that signature was a major PITA, had to do it over 100 times to get it right !
Camilo Silva F.
Camilo Silva F. Mastering
Chia, Colombia

regularjohn

Re: My GSSL Variable scale meter board....
« Reply #6 on: September 23, 2009, 09:51:47 PM »
Has anyone thought about making a variable scale meter for a gssl with a regular 1mA DC meter?

I was thinking if you tap from where the meter resistor is, and used a DPDT switch:

Pole 1 is input.
1K resistor across the top 2 throw lugs.
2K resistor across the bottom 2 throw lugs.
Pole 2 is output to meter.

That way one throw is 10dB scale, and the other throw is 20dB scale.
Would this work?
Just brainstorming here....
« Last Edit: September 24, 2009, 08:22:19 AM by regularjohn »
SATANOSCILLATEMYMETALLICSONATAS

ChrioN

Re: My GSSL Variable scale meter board....
« Reply #7 on: September 24, 2009, 01:27:59 AM »
I don't think a meter will be linear enough for that
"All PCB traces are curved to emulate the electrical response of point-to-point wiring" -Drip

regularjohn

Re: My GSSL Variable scale meter board....
« Reply #8 on: September 24, 2009, 08:25:52 AM »
Really?  Because essentially you would just be using the switch to change the series resistor for the meter to change between scales.
What makes you think it wouldn't work?
SATANOSCILLATEMYMETALLICSONATAS

ChrioN

Re: My GSSL Variable scale meter board....
« Reply #9 on: September 24, 2009, 09:05:16 AM »
What you are saying might be true. Try it out!
"All PCB traces are curved to emulate the electrical response of point-to-point wiring" -Drip


Silvas

Re: My GSSL Variable scale meter board....
« Reply #10 on: September 25, 2009, 04:14:12 AM »
Has anyone thought about making a variable scale meter for a gssl with a regular 1mA DC meter?

I was thinking if you tap from where the meter resistor is, and used a DPDT switch:

Pole 1 is input.
1K resistor across the top 2 throw lugs.
2K resistor across the bottom 2 throw lugs.
Pole 2 is output to meter.

That way one throw is 10dB scale, and the other throw is 20dB scale.
Would this work?
Just brainstorming here....

I remember seeing something just like you´ve described in this forum a while ago...like 2-10-20 dB GR scale on a needle...

Camilo Silva F.
Camilo Silva F. Mastering
Chia, Colombia

regularjohn

Re: My GSSL Variable scale meter board....
« Reply #11 on: November 02, 2009, 09:50:53 PM »
Here it is!  I did it!
I used a 2K trimpot in place of the meter resistor.
Ran that to pole 1 of the toggle switch.
Put a jumper across 10dB scale lugs.
Put another 2K trimpot across 20dB scale lugs.
Pole 2 is output to meter.

It takes some time to calibrate between the two trimpots for accurate metering for both scales, but it works!



« Last Edit: November 02, 2009, 10:01:24 PM by regularjohn »
SATANOSCILLATEMYMETALLICSONATAS

Silvas

Re: My GSSL Variable scale meter board....
« Reply #12 on: November 02, 2009, 11:33:47 PM »
Here it is!  I did it!
I used a 2K trimpot in place of the meter resistor.
Ran that to pole 1 of the toggle switch.
Put a jumper across 10dB scale lugs.
Put another 2K trimpot across 20dB scale lugs.
Pole 2 is output to meter.

It takes some time to calibrate between the two trimpots for accurate metering for both scales, but it works!





Nice unit BTW...

I was thinking on making a drum crusher GSSL with somewhat similar panel layout, crush´n blend, and a big needle meter.

Camilo Silva F.
Camilo Silva F. Mastering
Chia, Colombia

dennisp

Re: My GSSL Variable scale meter board....
« Reply #13 on: July 27, 2010, 03:27:36 PM »
Hi there,

Sorry for waking up such an old thread, but I would really like to know how you attached the control PCB (the one saying Ratio, Attack and Release)?

I looks like you have some very special spacers with corners just matching the height of the PCB... where did you find these? And how are they attached to the bottom surface of the box?

Sincerely,
Dennis
If everybody doesn't want to be normal, then isn't that normal?

Silvas

Re: My GSSL Variable scale meter board....
« Reply #14 on: July 27, 2010, 03:45:24 PM »
Hi there,

Sorry for waking up such an old thread, but I would really like to know how you attached the control PCB (the one saying Ratio, Attack and Release)?

I looks like you have some very special spacers with corners just matching the height of the PCB... where did you find these? And how are they attached to the bottom surface of the box?

Sincerely,
Dennis

Nothing special, really. I used a couple free holes from the lorlins i didn´t use then mounted the PCB to the bottom of the case with nylon spacers....

Camilo Silva F.
Camilo Silva F. Mastering
Chia, Colombia

dennisp

Re: My GSSL Variable scale meter board....
« Reply #15 on: July 27, 2010, 04:27:34 PM »
Doh!

Now that I know what to look for I see them clearly on the first picture  ::) inside the "rings" where the Lorlins should be  :P

Thanx!
Dennis
If everybody doesn't want to be normal, then isn't that normal?


 

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