cheapo 5V time ...

[Haible Juergen]

I know that using cheap components and low, single supply voltages are
not
a *real* benefit, when you consider that everything else than the mere
electronics
make up the price for a module or a stomp box or whatever.

But anyway, the recent response to the Wasp filter clone has triggered
some
experiments with 5V synth electronics. Take it just for fun, or (as I
do) take it
as an accompaining module for the filter in a separate processing box: I
spent
some time to develop little 5V powered envelope generators / LFOs.

The first thing is built around a 555 timer and a few discrete
transistors.
It has 2 potentiometers, Attack and Decay, and 3 switches to select
various
modes. Depending on the switches you can get 
1) normal Attack/Decay envelope
2) AD envelope which will run full cycle after short trigger
3) Attack/Release envelope
4) LFO with truncated expo function slopes, separate rise and fall time
control
5) A "repeat" function: A Gate will cause an Attack, then go into LFO
mode until
   Gate is turned off.
This circuit is tested, a schematic is drawn, and if there is some
interest, I will
scan it and make it available.

But I plan to expand this circuit to a full ADSR (should work with one
additional
CD4066), and then use this for my Wasp filter. Switch trigger input to
operate
it with a footswitch. (Wished someone would develop a cheap Midi-to-Gate
interface, remember the recent thread.)

All of this is great fun for me - develloping dirt cheap circuits from
standard
components, and take the challenge of very limited supply voltage.
Don't expect the envelopes to gow down to 0V. Don't expect AD and AR
modes
to have the same amplitude. Don't expect the LFO going negative (;->).

JH.