New Hammond organ project - L122, AO-43

[CasinoShanty]

Hey guys. I have a project similar to the ones that other people here seem to be tackling. I adopted this L122 organ that the local highschool was giving away, and it is in rough shape. The volume pedal slips, because the plastic gear is partially stripped. Also, some keys were broken. However, there is very little hum, and the speakers sound great.

I actually have the exact same organ, albiet a couple years older, in my basement. It was my go-to keyboard for working on musicianship skills homework in university. I always wondered what it would be like to tear it apart and plug a guitar in to see what it would do, and now I have a functional clone to mess around with.

So, I got a little anxious, and I stripped the organ apart already. I guess that was probably my first mistake. I am wondering now after the fact about whether or not I could have installed a 1/4 inch jack and plugged a guitar in to see what it would do. Anyways, if anyone has any suggestions as to how to make a guitar work in this sucker, that would be awesome. My plan is to keep it clean sounding, as I've heard these speakers were designed to reproduce the wide frequency range of the organ. I would like to re-use the drawbars, as far as I can tell they are just cool looking potentiometers. I also wouldn't mind re-using the spring reverb, since the amp has an in and out for it already.

Here's a plan that I am considering using, minus the arduino circuit.

Anyways, this is the big picture. I've read that these amps really need a preamp, and don't do a whole lot without one in front driving it. I have found a cool project for the percussion box that was also in the organ.

http://www.solorb.com/elect/musiccirc/f ... index.html

If anyone has suggestions as to where to start, that would be very helpful.

Thanks,

Andrew

[mike60510]

I was wondering if you had any luck with your conversion. I was able to garbage pick the amplifier and speaker from a Hammond M-2 organ and was thinking of the same thing. Don't know if its worth my time and effort

[Structo]

It depends on the model and year of the organ but I bought a Hammond M3 organ amp on ebay.
It was a late 50's amp complete with RCA 5U4GB rectifier, Sylvania silver top 6V6's.
And three or four 12ax7's.

My idea was to just simply convert for guitar use by simply changing just a few things.
These organs originally had field coil speakers that used the coil for a choke in the power supply.
These speakers don't have a permanent magnet, but instead use an electromagnet to power it.

It was all point to point terminal strip type wiring and soon after I got into it, I decided to strip it and just use the transformers and tubes.

I later changed it to a 6V6 Rocket type amp.

If I had to do it over, I probably wouldn't buy it again since I used so little of the original amps parts.

But if you just want to have fun and try something with it, go for it since you got it for nothing.