From: DougSYOlists@aol.com
To: hammond@zeni.net
Date: 1 Mar 2002
Subject: A-105/Motion Sound hook-up complete - details here

This is somewhat technical. If you want pictures, diagrams etc let me
know and I'll see about taking some.

After about a half-hour of investigation, I decided to give up on
resurrecting the 44W - the the power transformer has a shorted secondary
and the voice coil on the field coil woofer is open. There are also some
components that show signs of water damage, or possibly old age. I'm not
sure what I'll do with it, but I decided it's time to move on. Maybe I'll
part it out, the driver and motors work.

Alternatives were a nice-looking Leslie 415 - which it turns out wouldn't
have fit in my car and would have cost a bunch for an 11-pin cable and
commercial interface box (I could probably roll my own, this Leslie
doesn't pass 117V over the organ cable) - or a bit more for a Motion
Sound Pro-3T and LowPro that fit in my car. I chose the Motion Sound rig,
The guys at Pianos & Stuff in Pittsburgh area are great to work with.

Here's how I hooked it all up. I wanted the switches to be reachable from
the console, I wanted something relatively easy to undo externally (5
minutes behind the organ with a soldering iron would do it), I wanted to
not harm the finish of the organ. I also have to consider that this organ
has a finished back that I will not under any circumstances damage.

I built the line out adapter shown in BITB and on Motion Sound's website
to get a 1/4" output, in a little Radio Shack project box - jack on one
end, hook-up on the other end, pot on top (note: Radio Shack didn't have
the .001mf cap, I had to get that elsewhere). Because of the finished
back, I attached wires to the input of the AO-39 (output of the AO-28)
that extend about a foot from the organ and end at a terminal strip, to
which I attach the adapter with alligator clips. Why ? because now I can
use the same adapter at my church, which has an open-backed A-100. I
figure I'm not going to drill a hole for the jack anyway, so it doesn't
need to be permanent.

Next, I needed to deal with speed switching and controlling the internal
speaker. I got a project box at Radio Shack that was about 6" long, an
inch high, and two inches deep, a bag of 3 switches (2 SPST and 1 DPDT) a
20' cable with stereo 1/4" plug at one end (it was a headphone cable, I
cut the jack off, it was easier than rolling my own) and a roll of
4-conductor "rainbow wire". Motion Sound's website has the connection
information for alternatives to their foot switch.

The right two SPST switches hook to the Motion sound ... shield (sleeve)
goes to one terminal of both switches, red (tip) goes to the "fast"
switch and white (ring) goes to the slow/stop switch. Note that when the
fast switch is OFF it spins fast, backwards of what you would expect at
first. That's because it assumes fast if there's no speed control
attached. If you wanted to use a momentary foot switch (rather than
theirs) to run a MS, you have to make sure it's open when depressed.

The left-most (third) switch is using one side of the DPDT switch as an
SPDT switch. I had already moved the reverb amp connection to the back of
the AO-39 instead of the back of the speakers, because I knew I'd have to
do this to keep the reverb working without the main speakers. I brought
the AO-39 speaker outputs to a 5-lug terminal strip. The black wire from
the amp went to one side of an 8-ohm (probably should use two of them
since there's two 8-ohm speakers in parallel) and also to the black
speaker wire (you could move the reverb amp hook-up here, instead of to
the back of the AO-39 - and hindsight being 20-20, this would probably be
better). the green wire from the amp goes to a lug that goes to the
center of the switch.

The green wire from the speaker goes to another lug then to one side of
the switch, and the other end of the resistor terminates on a fourth lug
that goes to the other side of the switch. I used the rainbow wire,
cutting one off at both ends, to connect the switch and the terminal
strip.

Once this was all assembled and tested, I removed the switches and
fastened the box with two screws to the underside of the front strip of
the console, about the same place as half-moon switches would attach,
just below the presets. If I remove the box you have to look under the
organ to see the screw holes. I put the switches in again, closed up the
box, and tested it again... it works great! Then I taped portions of the
rainbow wire to the cable headed to the Motion Sound.

[Update: later in March, I moved the rainbow wire so it goes in through
the slot between the speaker front and the bottom of the manuals, so
it's not dangling off around the side of the organ. It looks much
neater.]

The first switch toggles between the internal speakers and the load
resistor. The second and third switch control the speed for the Motion
Sound. The reverb sounds from the console regardless of which position
the first switch is set at, and uses the normal control.

The only thing I can't do that a standard Leslie kit can do is turn
signal to the MS unit off from the console. No biggie to me, I can just
stop it from spinning, or get up and pull the signal plug.

Doug, who got very ambitious this evening
(Hey, if any Hamtech folk are watching, have I "passed the test" now ?)