Pitch/Voltage converter board ready at EFM

[Harry Bissell]

I've finished the Pitch to Voltage converter PCB and the results are on
TomG's
EFM site.
http://www.xavax.com/efm/pcb/pv1.html

Tom is taking orders, the price is $14 each, $1 shipping USA, $2
international. He's hosting the page for me at EFM, the schematics,
parts list, and PCB layout drawings are there.

The PV-1 converter is based on a design by Bob Moog for the Etherwave
Theremin sold by his company Big Briar.  I've modified the gating
circuit so that the frequency detection
is  more abrupt, and modified the P/V converter so that you can hold the
unit in reset mode with an external signal.  You need the gate circuit
if you use the Etherwave theremin, otherwise its a general purpose P/V
converter.  I've built two of them so far...

The board has the "Volume Control Voltage Output" mod for the Etherwave
on board,
so you can hook it up to the Theremin with just an 8 pin ribbon (molex
or AMP style) .100" cable. No other mods to the theremin are needed.
I've been playing my ProOne
deiven from the Etherwave and it is GREAT.... dual oscillators...
sync... wind and waves noise sweeps.... you get the picture...

Other uses: Guitar -  If you plug a Guitar right into the pitch input,
it will track tolerably well on the lower notes.... It really needs some
preconditioning to track reliably over the whole range... but "blow me
down" I didn't expect it would outperform my 360 Systems
"slavedriver" right off the bench!!!  If you use a hex pickup it would
work better. Of course I'll be working on interface circuitry for guitar
and I'll post any breakthroughs I make.

Keyboards: App #1 If you have an extra "digital" keyboard laying
around... you can use the PV-1 as a Midi to CV interface... The Midi
drives the Digital Keyboard (use a sine or ramp wave with minimum attack
and decay)... run the audio output into the PV-1, and
send the CV out to your analog stuff... Not perfect... but quite usable.
Some keyboards
have too long of a minimum decay time, and the pitch can go off if that
happens... The Emu Proteus MPS worked fair... the Korg DW-8000 was
excellent. The volume levels make quite a difference...

Keys App #2  You can run the oscillators from a V/Hz unit (like the
Fatman) and use the PV-1 as a V/Oct converter. If you go direct from the
oscillator you will have no problems
like described in keyboard App#1. The oscillator will always clock
without any "decay" problems, so the CV out will be rock steady.  This
is a good cheap way to bridge the gap between systems...

Thanks go out to Bob Moog, who gave his kind permission for me to make
the Etherwave Pitch to Voltage design available to people as a PCB, and
to TomG who
is handling all the nasty web related stuff at his EFM site.

I'm writing a technical description of what I've done, and will post
that at EFM when it is complete. I'm happy to answer any general
questions anybody has on synth-diy or EFM lists. For specific advice
contact me off list.

H^)   harry