[sdiy] Tonewheel questions

[john mahoney]

I should be in bed, but noooo, I'm checking my e-mail. Ugh! Ok...

----- Original Message ----- 
From: Robotboy8 at aol.com


> 3) How many wheels is it reasonable to have on the shaft?  (As I said,
> I'm thinking five, but could be swayed in either direction).

The limit is matter of total mass & friction vs torque, other factors being
desired size and weight of the unit.


> 4) ... What should the line-out level be?  And howsabout a 'to
> modular out' level?

Modular level is typically +/-5V, rather "hot" compared to most line outs.
If you plan to use this with synth modules, go for that output level.
Otherwise you want more like +/-1V or less. (Second opinions...?)


> 5) What's the cheapest sort of inductors to use?  I don't like the
> sound of guitar pickups, they end up as a little more expensive than
> I'd like to use.  I would like to have separate ones for each wheel so
> I can use pots as 'drawbars'.

You can wind your own pickups. A magnet, some wire, and you're all set.
(Instructions are assumed to be findable with your favorite Web search
engine.)

Why not optical tonewheels? Paint the tonewheel edges white or silver, use
LEDs and photocells.

Optical tonewheels can also use black & white patterns (reflective) or
transparent wheels with opaque masks (transmissive). Actually, you can use
shades of gray, too. A radial array of done in white-to-black gradient would
create a sawtooth. Look into optical soundtracks of movie theatre projectors
for more info. Probably treading on some Optigan patents, now!


> 6) Unrelated, but I have a keyboard labeled GC-7A.  ...

> ... It has an output labeled 'karaoke' but no line
> out, which shares some solder with the 9v in (I run it from
> batteries).  ....

That shared solder would likely be the circuit's ground point.
--
john