Hammond M2 and M3 organ

[Pdavis68]

I've come across a deal I think I'm going to jump on. A local guy is selling an entire Hammond M2 organ (has been in storage for 15 years but the electronics, at least, appear to be in decent condition). He also has some of the parts from an M3 organ, including the amplifier.

I don't care to own an organ, but a conversion interest me. I've seen that some people here have done organ amp conversions to guitar amps. What I'm curious about is, what did you do with the other stuff. I think there might be a reverb unit it, so I may reuse that. I'm getting everything for $50, which seems like a steal. I'm guessing the speaker (15", I believe) won't be any good for guitar. Is it worth my time to try to sell the parts on e-bay? I was going to probably keep the side boards, top board and front board. I'm not sure what the wood is, but it looks like it might be mahogany. That could come in handy.

He's selling everything for $50, so it seems like a real bargain.

[Enzo]

And tons of wire.

[olddawg]

That's a great deal if you have the back for it. The speaker is more than likely a 12" Jensen which is an excellent guitar speaker for lower wattage amps depending on your tastes. I had a friend pick one up for $50. I put a line out circuit off of the speaker and he used it in his home studio. Visiting keyboardist love it. But yeah, it's also a great chassis for conversion. Then a lot of land fill.

[DRH1958]

There is a lot of extra tone shaping circuitry on the main chassis of this organ. The three tubes on the right go through coils for signal processing and are pretty useless for guitar. You should check for the reverb amp on this organ. The main chassis does not process the reverb; this is accomplished by another smaller amp. If this is an older model, it will have an AO-35 reverb amp in it that has two 12AX7s and two EL84s plus a 5Y3 rectifier tube. This is the amp made famous by Dr. Z as the basis for his Carmen Ghia. This amp is much more mod/rebuild friendly than the main chassis for sure. A newer model will have an AO-44 reverb amp and this is an amp that has two 6GW8 tubes which have a triode and output pentode in each bottle. This has an EZ81 rectifier and is also a candidate for rebuild, but the AO-35 has more robust trannies. I would definitely scoop this one up. You could get two amps in one organ. There is plenty of info out there on modding/rebuilding the AO-35. I think this is the real gem in this organ,not the main chassis.
As Enzo said, save the wire bundles. There is enough wire there to last you for a long time.

[sgelectric]

I used to own an M3. Not sure of the date of manufacture.
IIRC the speaker was a field coil design.

SG

[Pdavis68]

That's good news about the speaker. From the photo I estimated it was probably a 15" speaker, but after a bit of research, looks like it probably is a 12" Jensen. That'll be nice to have.

With the main chassis, my plan was just to gut it and start over. Reuse the transformers and some of the tubes, but otherwise gut it. It would be too much work to try to rewire it. There's so much stuff going on inside of it, it would be impossible to do anything clean and safe.

I had forgotten about the reverb amps being separate. I've seen some of the stuff on converting those. So I may end up with 3+ amps out of this deal! I don't know what all is in the M3. I emailed the guy asking for some more information. I'm trying to find a friend with a truck who's available for the 2 hour trip and willing to help. I have one friend who's a guitarist who I've offered one of the rebuilt amps in exchange for the help.

I'm hoping the wood is mahogany or something equally valuable. I bet I can find some local woodworkers willing to part with some cash for that.

[Pdavis68]

Also, I'm curious for anyone with experience with an M2 or M3: How difficult would it be to completely disassemble and break down the organ cabinet. If I could break the whole thing down, it would probably fit in the back of my Honda Element. If I could do that in an hour or so, that might be easier than trying to get access to a truck and help from someone to load it.

[olddawg]

Also, I'm curious for anyone with experience with an M2 or M3: How difficult would it be to completely disassemble and break down the organ cabinet. If I could break the whole thing down, it would probably fit in the back of my Honda Element. If I could do that in an hour or so, that might be easier than trying to get access to a truck and help from someone to load it.

Truck or chain saw, lol!

[Pdavis68]

I seriously considered taking a circular saw, but the guy's selling this thing he's had for at least 15 years. He probably doesn't want to watch me literally chop it up in his driveway... But I'd be totally fine with it myself. It's just lumber as far as I'm concerned.

[DRH1958]

I have scrapped two organs and have had three woodworkers tell me the wood cannot be re-used because it is veneer and will chip when cutting it. I asked about the masking tape trick where you tape the wood first and cut through the tape so it holds the veneer in place and they told me it doesn't matter, it still chips. See if you can just buy the amps from the organs and tell him you will help break down the organ to trash it. Save the wire and reverb tank too. But remember, the main amp chassis does not amplify the reverb signal. It has its own speaker that mixes with the signal form the main amp. There should be a 12" or two for the dry(main) output and an 8"(usually) for the wet(reverb) signal. They mixed signals this way instead of having a separate wet and dry signal path in the same chassis like a Fender or others.

[DRH1958]

M2 pic

Here is the back. The reverb amp is on the right, in this case, the AO-35
You will be super lucky if yours is half this clean!

[Pdavis68]

This M2 does not have reverb unit.



It's a little dusty, but I've definitely seen worse.

Thanks for the details. I'll see if the guy will be okay with me just taking the guts and leaving the wood to be scrapped. If I can disassemble the whole thing relatively easily, I'll do that and dump it for him. Not a big deal to me one way or the other.

[DRH1958]

Ah, sorry, didn't know it was THAT old. I guess they started reverb with the M3 or M100 model. This line was the most popular Hammond at the time with a ton of changes and upgrades along the way. Here is a link to some schematics: http://www.captain-foldback.com/Hamm...schematics.htm

[Pdavis68]

Yeah, been to Captain-foldback. Great site. Based on what I've read so far of the service manual, it looks like the M100 might have been the first with the reverb unit.

[Pdavis68]

In the Hammonator, he discusses the the fact that the transformers were designed for 110-115V and at 120V the filaments will run hotter and he offers up a way to fix this by putting the 5V filament winding in series with the primary. Are there any safety issues with doing that? Could you not just create a voltage divider to take away the bit of excess? I might want to keep the 5U4.