[sdiy] Tonewheel questions

[John L Marshall]

I think that a motor designed specifically for variable speed would be a better choice than a fan motor. A sewing machine motor and control would be a good choice. Hmmm. How about an old blender motor with 8 push buttons? You need a series wound motor. AC only motors require VFO (variable frequency oscillator) to change the speed.

Take care,
John
  ----- Original Message ----- 
  From: Robotboy8 at aol.com 
  To: synth-diy at dropmix.xs4all.nl 
  Sent: Thursday, May 27, 2004 8:50 PM
  Subject: [sdiy] Tonewheel questions


  I'm thinking of building a vastly simplified tonewheel organ.  What I'm looking at doing is a fan motor running off of wall-current with a dimmer (the kind used on house lights) to vary the speed of the motor (overall pitch), this motor being connected to a shaft with 5 (or howeverman) wheels.  My questions are as follows:
  1) Will the fan assembly work?  I know some fans don't 'like' lower currents than they're used to seeing, what sort are these?
  2) Anything I should know about these dimmers beforehand?
  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).
  4) It's mainly for drones, so a dimmer as pitch control isn't a problem and no EG's shouldn't be a problem, but what about output level?  What should the line-out level be?  And howsabout a 'to modular out' level?
  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'.
  6) Unrelated, but I have a keyboard labeled GC-7A.  It has no maker label on it, and basically outputs a square wave with pitch determined by key being pressed.  Ugly sound.  It has two 'timbre' controls that change the sound - one seems to add tremolo, the other something I can't quite identify.  It has an output labeled 'karaoke' but no line out, which shares some solder with the 9v in (I run it from batteries).  I'm thinking I may circuitbend it, but I can find no info whatsoever on it.  Anyone have any clue?  Oh, and it plays a wide selection of obnoxious Christmas melodies.
  (I got it for 2.50 USD from the thrift store.  Maybe if I didn't blow all my money on crap like that I could afford the 100 dollar organ they have, unlabeled maker but it has enough stops that it looks like fun).
  Any help much appreciated.
         -eric 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20040527/379272c3/attachment.htm>