[sdiy] Photocell/LED distortion question

[Ralph]

More then makes sense. There is a hi-fi application of this techniques where a fiber optic cable is used with one of the newer led encoder chips that has a feedback output to allow for low distortion. The cable replaces regular interconnects. Long distances are no issue, and you can finally have a straight wire with gain.

-Ralph



From: Robotboy8 at aol.com
To: synth-diy at dropmix.xs4all.nl
Subject: [sdiy] Photocell/LED distortion question
Date: Tue, 8 Feb 2005 22:37:22 EST
Sender: owner-synth-diy at dropmix.xs4all.nl
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I had a thought a while back and the other day it refined itself in my brain 
enough to actually have some clue how I might execute it and I'm wondering to 
what extent it would be worth pursuing this further (I'll probably end up 
x-posting this to some guitar forums soon, as it's really got more to do with 
guitar pedals than synths I guess).

Basically, take a standard opamp-and-two-diodes distortion circuit, build it 
using LED's, and then use the light from the LED's to control either the gain 
of the opamp or of a simple VCA (any clues which?) so that you can have 
distortion without losing the dynamics of the signal - play soft and it will be 
soft, the shape of the wave changed but not the volume.

Make sense?  Feasible?
       -eric