MOTM

Oh, that's good information to have.  I used to have a farfisa organ with
that same optical type arrangement for volume.  Any idea what voltage was
supplied to the bulb or what the actual TRS connections were?

Stranger yet were the methods Hammond used to avoid pots for volume in his
organs. Some consoles like the B3 used many switched fixed resistors.  And,
I had a spinet (M2 I think) that actually used a big variable capacitor that
reminded me of a low frequency radio receiver tuner.

Larry H.

----- Original Message -----
From: <WeAreAs1@...>
The foot pedal you have is a model FC4.  The pedal they are currently making
is the FC-7.  The old FC-4 is an opto-electric pedal.  It contains a small
incandescent light bulb and a photoresistor.  Two of the TRS plug conductors
are connected to the photoresistor; the other conductor supplies DC voltage
to the light bulb.  Movement of the pedal opens and closes a small shutter
between the bulb and the sensor, allowing in or shutting out the light from
the bulb.  With no power applied to the lightbulb, moving the pedal (opening
and closing the window) won't really change the measured value of the
photoresistor (it's dark in there!).  This is in contrast with the newer
"passive" FC-7 pedals, which are potentiometer-based, so their resistance
can
be varied with no power connected.

For more reasons than one, it's probably a better idea for you to try to
obtain one of the newer pedals for use with your analog equipment.

Michael Bacich





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