From xxcaptinxx@comcast.net Sun Apr 15 22:23:24 2007
Subject:Re: OT:Hooking up an A100

The 44W must have a lot of mods, because stock it uses a field coil speaker
and driver which need to be energized by the 44W power amp. Have the
speaker, driver and crossover been replaced? If so does the impedence of
the new combination match the PA output?

The correct way would be to install a Leslie 6147 or 8444 kit and cable so
that you can use switches to feed signal to the main speakers, Leslie or
both. If you're not going to use the internal speakers, pull the tubes on
the power amp at the rear lower right of the organ. However, you will also
lose the signal that feeds the A100's reverb amp if you do this. If you're
going to leave the internal speakers on all the time, just add the line out
described below:

You can solder one side of a 100 ohm 1/2 watt resistor to one of the two "G"
terminals on the AO-28-5 organ preamp, with the other side of the resistor
soldered to one side of a 10 uF 50 volt capacitor. Cut a 10 inch length of
20 gauge or bigger wire, strip 3/4 of an inch, and secure it under the screw
that holds the air cap shield onto the pre-amp, as a ground wire, and at its
other end solder a 100,000 ohm 1/2 watt resistor. Cut another short wire
and attach it to the "tip" of a 1/4 inch socket. Solder the free ends of
the cap, the 100K resistor and this second wire together. Depending on how
your PA amp is wired, you may then just run a guitar cord between the socket
and a 1/4 inch input on the PA. If you get no sound, you may need to solder
a third wire from the "ring" of the socket back to the organ pre-amp chassis
(ground) to complete the circuit (but this may also cause a ground loop).

A different way to do the deed is purchase a balanced audio transformer that
is wound 1.1 to 1. Turn it around so that the primary is attached to the
pre-amp ( G-G and chassis ground) and the secondary side (two wires) is
attached to a 1/4 inch socket, guitar cord and off the the PA.

A third way would be to use a passive direct input (DI) box, attaching the
green, black and a chassis ground wire from the organ pre-amp to the input
and using a mic cable to connect to a balanced input on the PA. If the PA
has a seperate mic gain and master gain, set for former low and the latter
high until you get a SN ratio and volume you can tolerate.

There is yet another method that taps the organ signal from the red and
black connectors on one of the A100's speakers using an L pad.

It would be a good idea to use the PA EQ to roll off everthing over 6000 Hz.
If you'e going to use the internal speakers all the time, there is also a
way to wire the reverb amp's output so that it is mixed before going to the
PA. Some people like that sound, some don't.

Of course, the speed switching system is entirely independent of the
connections described here.

Regards,

Dave Bishop