On Sunday 16 April 2006 17:38, I.F. wrote:

A better alternative is to re-post on alt.binaries.schematics.electronic as
I have sketched a basic circuit, but as I find math highly tedious I usually
do just enough to get by and determine most of the values by experiment.
There are some great engineers on a.b.s.e so you might get some even better
circuits to try.

I'm going with this one: http://sound.westhost.com/project39.htm

If all goes right, the MOSFET switch should prevent chatter, because of it's
fixed turn on voltage.