Hammond delay thingie (was: mysterious delay lines)

[Don Tillman]

   From: Hcabnivek at aol.com
   Date: Tue, 4 Aug 1998 11:57:06 EDT

   Speaking of delay like devices (though I'm not sure this real is
   one) can someone explain how the small motor driven drum inside a
   Hammond organ that has all the wires connected to it works to
   generate tremolo/varabrato.

The Hammond service manual is readily available online (gotta love
the internet!) and has the complete explanation.

http://theatreorgans.com/hammond/faq/a-100/a-100.html

It's a tapped LC delay line, a 3-position range switch to select eight
of the taps, and a rotating mechanical scanner to fade between the taps.

   Date: Tue, 04 Aug 98 11:38:53 -0500
   From: "R.G. Keen" <keen at austin.ibm.com>

   Sounds like an oil can delay. 

That's a different beast.

Oil delays are used only on those Moreley and Gibson echos, as far
as I know.

  -- Don