how to use the LM386 and LDR to reduce carrier bleed in the thing modulator?

Started by breather-resistor, March 20, 2008, 12:22:56 PM

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breather-resistor

I know there has been plenty of talk about this topic but has anyone actually done it or at least come up with the diagram for how it works?

Breather

mattusmattus

here here squire, I'm too wondering how you could do it. I naively ordered some lm567s instead of lmc567s. I'm guessing you need an led that dims when there's a guitar signal coming through and an ldr  shunting the output to ground?
Any ideas?

alex frias

Pagan and happy!

any

I actually have a working prototype using this setup, I thought I was the only one working on such a set-up...
Guess not! It's currently being used by a friend of mine on the other side of the planet which makes it hard for me
to disclose all of it, but that said, this is what I still know about the circuit I've build:

Ugly-face front end driving a pair of led/ldr combos, one ldr going to the frequency or speed control
(mine was selectable and based on the "MayheM! that I built earlier and you can find it in the layout gallery in the album
called "ANY Machines". this version has both "speed" and "frequency" a simple dpdt toggle will do the job).
The other LDR was what I think was quite novel, it was wired as a resistor between the circuit output and the actual
output jack. a resistor (forgot exact value) went from circuit output to ground (before the ldr) which ment when notes were played
the ldr would go from 1M+ to about 50 Ohm effectively "opening" the effect. With no notes played the ldr would swing back
up to 1M+, forcing the signal to ground through the resistor. It works very well and even reacts to the playing envelope
because of the sensitivity control (as on the ugly face). It made for a lot of fun because it was dead-quiet when nothing was
played but when you hit a single note this wall of noise instantly took over...  ;D

I've asked him to send the pedal back to me because technically I was still working on it.
I had a 6 pole 4 throw selector switch to switch to different modes of envelope control
and circuit bends which still needs one mode to be wired up.
In addition to the massive "program selector" it has 4 pots (sensitivity/gain/speed/frequency) a toggle for different led to ground combo's
which producing a variety of sequence like trails in the lower octave sounds. And a toggle for yet another
LDR mounted on top of the box.

Is your head spinning yet?

When the time comes, I'll put the full schematic up here...
It's supposed to sound that way.

syntaxera

any updates on this?

I was starting to think about a LM386 to kill the clean channel whine of the LM567 in my Thing Modulator.  My train of thinking is maybe with an OpAmp in line I could split the inputs completely, hence taking the oscillator signal out of the ground . 

Now to just figure out how to do it, and wire it true bypass.  Seems like hours of trial and error for it to MAYBE work. 

Does anyway know for a fact that the LMC567 doesn't have the same problem ? I see a lot of folks talking about it, but none who have actually tried it. Well I just ordered a bunch either way.  We shall see..  lol