Really Cheap Compressor. New with LDR + compression led indicator

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Really Cheap Compressor. New with LDR + compression led indicator

nonost
 Hi! I'm going to build a Really Cheap Compressor as a part of a large build. It's my first time with LDR+led. I'm following this layout:

http://tagboardeffects.blogspot.com.es/2012/03/really-cheap-compressor.html

 Some people recommend to test some LDR and use the best that fits the needings, should I get 3 or 4 LDR and test them? what should I exactly test? I'm ordering a 8k-20k (light), 1M (dark) one.

 For this layout  3mm green leds are needed, I'm going to order them to Musikding. They also offer a bright 3mm green led. What do you think that will work best? I know that I can get both and try them but since I have to put the LDR+leds in the heatshrink and all that stuff...it would be a PITA.

 The other subject it's about adding a compression led indicator. I've seen some builds of this compressor with it, but the owners don't say how to achieve that. I guess that I should use one of the LDR+led rows but I don't know exactly which one.

 Any help is very welcome :)
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Re: Really Cheap Compressor. New with LDR + compression led indicator

Ciaran Haslett
The problem with "home rolled" vactrols (a separate LDR and LED heatshrinked together) is that it opens up the number of variables that can introduce problems.  The specific LDR specs, the amount of light from the LED, the LED beam angle, the ambient light isolation etc etc.  That's why its always best to get as much variety as you can when ordering these kind of parts.

I wouldn't heat shrink until AFTER I've tested a combination...either with some electrical tape or simply in a dark room with a box or something over the whole build.  When I've found a combination I'm happy with...then I heat shrink it move on.

As for the compression indicator...just add another LED in parallel with one of the 2 on the board.  You may need to add a small value resistor in series with this new LED to isolate it from the others but as they are rectifying the guitar signal I don't think that's necessary.

Good luck
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Re: Really Cheap Compressor. New with LDR + compression led indicator

Boba7
I found that adding a parallel LED produced more distortion with higher compression settings.

I used this little circuit to add an indicator led : http://www.madbeanpedals.com/forum/index.php?action=dlattach;topic=24296.0;attach=14856;image
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Re: Really Cheap Compressor. New with LDR + compression led indicator

nonost
In reply to this post by Ciaran Haslett
Thanks man! I will order a few of them and use sockets in that case. Testing in a dark room sounds nice! I will post here how it goes.
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Re: Really Cheap Compressor. New with LDR + compression led indicator

nonost
In reply to this post by Boba7
Ey Boba7 thanks! I think I can put that circuit in a vero without problems. In the RCC, the 'A' red dot of your schematic would be right before Sustain 3?

This is the layout I'm using: http://tagboardeffects.blogspot.com.es/2012/03/really-cheap-compressor.html
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Re: Really Cheap Compressor. New with LDR + compression led indicator

Boba7
Yeah exactly, pin 7 of the opamp / pin 2&3 of the compression pot

Glad to help! Post some pics when it's done! :)