[sdiy] Random generator - Monotron Schematic - Guard Rings

[Dave Manley]

On 11/5/2010 1:58 PM, Ingo Debus wrote:
>
> Am 05.11.2010 um 18:54 schrieb Harry Bissell:
>
>> They look like a sawtooth VCO whose frequency is set by whatever the last sample
>> voltage was... kind of a way of "shaking the dice" at different rates each time...
>>
>> Clever, wonder if it works well... sure is simple (no noise generator needed)
>>
>
> Is this an answer to my question re how the random voltage generator in the Steiner Synthasystem works?
>
> So the UJT is the discharge switch of a relaxation oscillator?
>
> Making an analog random generator this way is pretty brilliant. Hats off!
> And then there's two of them in one module that can be run with the same trigger signal (if no plug is inserted in the trig 2 input). I wonder how similar the outputs are?

It's a clever way to start new discussions, you answer one thread under
another one, and see what happens. 8^)

The circuit isn't really random it just depends on the sample clock being
asynchronous and much slower than the relaxation oscillator. I spiced
it (but used a voltage controlled switch instead of the UJT) and got
a freq range from about 100Hz to 12KHz

Tying the previous sample CV back to control a VCO (VCLFO) is
interesting though - time to go patch that up, and vary the
sample clock, and scale the control voltage to the oscillator.
It might generate some interesting patterns.  I wonder if that's
in Strange's book.

-Dave