[sdiy] Tonewheel questions

Fri May 28 10:43:12 CEST 2004

The point of a synchronous motor in Hammonds was to keep the pitch from
wavering. Hammonds are shocking when run from small petrol generators!

For a simple way to experiment, take a look at old video players. In a lot
of them you will find some kind of feedback mechanism on the capstan motor
or video drum motor. These sometimes take the physical structure of a tone
wheel.

Ken 

>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
><HTML><FONT FACE=arial,helvetica><HTML><FONT  SIZE=2 PTSIZE=10
FAMILY="SANSSERIF" FACE="Arial" LANG="0">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:<BR>
>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?<BR>
>2) Anything I should know about these dimmers beforehand?<BR>
>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).<BR>
>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?<BR>
>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'.<BR>
>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.<BR>
>(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).<BR>
>Any help much appreciated.<BR>
>       -eric</FONT></HTML>
>
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>