Back on track

[J. Larry Hendry]

> From: harry <harrybissell at prodigy.net>
> Hey wow...
> ON TOPIC what a concept.

Be careful Harry.  Somone may drop a tube or BDD on your head.  :)

> Check out the Hex thumbwheel switches at MPJA.com
> They are only $0.50 each (for 2).

I have always liked these little thumbwheel switches and have been
looking for just the "right" application to include some in my modular.
So, how about a discussion on the merits of thumbwheel switches
as MMIs for modular.  Obviously, some applications might make
a decent interface while others would just stink.

One idea I had that is not fully developed is using them in a normalling
scheme between modules or module functions.  Let's here some others.

At the risk of showing how basic my understanding of this whole concept, and
to have something DIY to post to support the "back on track" theme, I am
including a link at the bottom to my VERY modest website.  There are two
circuits there which are designed to be used with any 1-volt-octave VCO that
has continuous tuning only.  I like octave switches.  This project developed
around that preference.  It adds octave and other interval switching to any
VCO.  There are two versions.  One provides 5 convenient shifts up and down
while the other provide shift to any interval.  They can be used for on the
fly jumping to intervals or transpose, or ??  I find when I have these
intervals at my fingertips, I tend to layer my VCOs with more than the
traditional octave or fifth intervals.

The circuits are shown built on a MOTM protoboard (my modular is built to
the MOTM panel format).  However, I now have PCBs available for $15 each for
both of them.  That price is designed around a "break-even" strategy.  I
could send the PCB artwork to anyone interested if you would rather roll
your own.  But, I would have to check first with the person who did it for
me since the layout is his intellectual property.

Credit for the circuit belongs in two places.  First to the authors of books
on op amps which I am just beginning to get a basic grasp of.  Second to
Paul Schreiber who has answered 1000 stupid newbie questions of mine over on
the MOTM list.  In fact, the output driver circuit was blatantly stolen from
one of Paul's designs.

To most of you, I know this circuit is simple as they get.  However, it is:
a - DIY
b - On topic
c - handy

Larry Hendry
Thankful to all that contribute.
Self proclaimed expert (by profession) on high voltage and mains.