[sdiy] Doepfer Ribbon progress

[harrybissell]

OK I got it working

I use a constant current source to establish 5V across the ribbon
(one side is still at ground) and I made the wiper run to a small
capacitor, buffered with a TL072 opamp.

The constant current source guarantees that the current through
the wiper (and cap) will never exceed 300uA. That should not
degrade the ribbon.

Lift your finger and the voltage is held. Its quite cool.

Next...  maybe a two voice quantized ribbon ???

I'm thinking of an instrument that had two Doepfer ribbons
side by side in place of a guitar neck... with quantizing
you could play simple harmonies. Maybe even a two-handed
stick type technique ???

I got this one used. New ribbons are a bit more dear, so it
would be an expensive project. OTOH with no wimmen in the house
I'll save that much in toilet paper... in a month :^P

H^) harry

Harry Bissell Jr wrote:
> 
> I have made more progress with the Doepfer
> Ribbon controller.
> 
> I tried adding the Moog design single bus
> keyboard controller to the ribbon.
> (actually its the EFM KBD2e clone of same)
> 
> I have not gotten the gate to work yet. I don't
> really care.  What it DOES do is allow the ribbon
> to retain the last voltage played, at least long
> enough for my quantizer to process the end of the
> note correctly.
> 
> Problem is... the USB connector has a GROUND
> connection on the shell... which is also one
> side of the position ribbon.  The Moog design
> floats both sides of the resistive element.
> 
> I'll work that out tonight. As I'm not doing the
> Gate connection, I can probably bypass that...
> 
> H^) harry