[sdiy] Wanred (dead or alive) : Pot

[Tim Parkhurst]

On 8/16/05, harrybissell <harrybissell at prodigy.net> wrote:
> The center tap is the most efficient way imho.
> 
> Any other great ideas out there ???
> 
> H^) harry
> 
> WeAreAs1 at aol.com wrote:
> 
> > In a message dated 8/16/05 7:24:53 PM, harrybissell at prodigy.net writes:
> >
> > << I want to do a 'center off' mixing function. Turn left, it
> > goes left only and the right is dead. Turn right, it goes
> > right only and the left is dead. >>
> >
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The Oberheim SEM is packed with special pots like this. They used a
pair of dual concentrics for the VCO tuning (coarse and fine controls
in only one panel space), center tapped pots for the mod amount (turn
one way, you get PWM, turn the other way, you get FM), and a pot with
one or two taps and a switch to select filter modes. The SEM is cool,
but I sure wouldn't want to try and replace all those pots.

How about taking a regular pot and cutting the resistive trace in the
center? You then need to solder a couple of wires to the trace (on
each side of the cut) for each side of the center tap, but I would
think this could work. Then again, I've been wrong before. Several
times just today, I think. ;)

What the world REALLY needs is a modular potentiometer. I know there
are companies who say they have this, but you have to order five
thousand of the darn things to get something special. What I mean is a
set of hardware that you could slap together to make a single or a
dual, it could be concentric or common shaft, and then you pick a
resistor element, add a turn/off or pull/off switch if you want, and
off you go! Yeah, I know, sounds a lot simpler than it would really
be. Still, I think it could be done.

And finally, what about cooking/melting/etching or somehow creating
your own resistor elements? Could this be done? Wouldn't it be cool if
you could whip up a batch of reverse log 5K pots (or some other odd
setup)? Once again, there has GOT to be a way... get a ceramic disk,
sprinkle on some graphite powder, cook at 450 degrees for an
hour...etch VERY fine lines in a metal plate...fire up the Delorean,
jump to 2250 and ask Captain Picard if you can bring back a
'replicator' with you...Come on people, how about some ideas here?!?


Tim (we put a man on the moon, but we can't make new ARP sliders) Servo
-- 
"Imagination is more important than knowledge." - Albert Einstein