homebrew vactrols

[CCartCat at aol.com]

FWIW, goofytech ideas lite on hard fact/heavy on aesthetic fancy:

I was inspired by a dirt simple implementation of the LDR that Lovetone 
offered in its newest pedal (forget the name).  Saw in a recent Guitar Player 
mag how a LDR wired into a 1/4" plug that's plugged into the L-tone pedal 
could control the depth of a control osc.  This is something like H. H.'s 
opening the Meatball and flashing a light across the bare LDR's. 

I plugged similar LDR rigs into a Korg X-911 (me being a mere 
lurker/hanger-on here, my only CV controllable synth gear).  One into the CV 
pitch, one into the filter cutoff, one into the trigger in--that sort of 
thing.  I set up in a dimly lit room and used a strobe light to drive the 
synth via the LDRs.  As was done with the opened up Meatball, I'd flash a 
flashlight across say the filter LDR to open the filter more or the trigger 
and the filter so pitch reduced to some nominal level below the spike created 
by the strobe but the synth continued sounding.  I played a bit with a mirror 
and cardboard to reflect/block light.

Obviously, whether you were up for some environmental installation with this 
kind of set up (macro scale) or some compact, more controlled enclosure (the 
micro version) this has some neat possibilities.  A low level light source 
can serve as an offset for one or more CV inputs while a periodic or more 
punctual source like the strobe plays against the constant.

And another irrational cousin to this would be a multi LED/one LDR black box 
CV summing amp--a situation where you intentionally be allowing the different 
oscillations/offsets of the LEDs to distort and swamp each other approaching 
the point of saturation.

Hope I'm not wasting bandwidth reinventing the wheel.  Just have more ideas 
than time/energy and thought these stray ideas would apply/up the 
inspirational ante.

:-)
Kevin Seward





In a message dated 4/18/0 5:38:07 AM, you wrote:

<<I owned a Lovetone Meatball filter pedal for about two years.

(recently sold it.) This filter pedal uses two LEDs that illuminate

one LDR each, but no optical isolation is used. So when I open up 

the case, the frequency of the filter changes. And when feeling

funky, I could wave a flashlight across the PCB area where the

LDRs were mounted, and the light would go through the PCB and

make a nice "quaka-owuicka" sound, if you take my meaning.


Cheap solution in an expensive pedal. (£199 direct price)


Hallgeir


BTW: those LEDs were green.>>