Hammond M2 and M3 organ

[Pdavis68]

I convinced my wife to let me take an advance on my allowance, so I'm buying 4 amps from the guy (she was actually really excited/relieved that I'm not buying an entire organ). I'm getting the L100. This is an amp he actually began a conversion into a guitar amp. I'm not entirely sure how far along he was, he's got some of it wired up (power, standby, 1/4" jacks, etc) so that'll save me some work & money. Getting that for $50. And for $100, I'm getting 3 PAs: A Precision Electronics 60PA (60 watt), a Davis Amplifiers 201-A (18-20 watts), and a Bogen Challenger CHB 35A (35 watts).

I've found schematics online for all but the 60PA, but I can get a service manual for it on ebay for $10 or so.

The Davis 201-A has 3 channel, 3 stage preamp, 6EU7 tubes, which I'm under the impression are like 12AX7s with a different pin-out, a 6EU7 PI and 2 EL84 power tubes.
The Bogen has 2 channels with 6EU7s as the 1st stage, 12AX7 in 2nd and 3rd stage preamp. It has 7868 power tubes (don't know anything about them or how they'll be for guitar, but something different.)
Not sure of the layout of the 60PA, but it has 3x 12AX7s, 2 EL34s, a 6973 and 2x 5U4s, according to an ad I saw for it. Radiomuseum says it has a 7025 in addition to the others.

The L100, of course, is a an organ amp and I think it's got some 12AX7s and EL84 power tubes.

Looking forward to having some fun toys.

[g1]

7868 is essentially a 9pin version of 7591. You will find them in some Ampeg, like Gemini & others.

[bluto]

Well, I just got off the phone with the guy. He's not so anxious to have his old organ chopped into bits and he has someone else who wants to keep it intact who might pick it up tomorrow. But then he went on about all these other amps (like an amp from an L100 series which has EL84s) he has (apparently he spent a lot of his youth picking this stuff up at estate sales and such and has quite a collection). He actually did a conversion himself about a decade ago, so he understands what I'm after. Anyway, he's going to make a list of what he has and e-mail me tonight. So looks like I'm going to be taking a slightly different tack on this. Glad to not have to deal with all the wood, though :-) That was turning into a headache. Kind of wish I had more money to buy a few of them from him. Sounds like he could keep me in the amp conversion business for some time...

I got 2 for free or very low $$$ recently, one was not tonewheel and not worth saving, one was tonewheel but was left outside so also not worth resurrection....anyway got two excellent tube amps and disposing of the carcasses was not all that difficult, they were fairly easy to cut up small enough for the trash can using a Sawzall. There are plenty of them out there that can be hacked up in good conscience but that one looks too nice for that IMHO, I do see them on Craigslist occasionally.

[Jazz P Bass]

Too big.
Too heavy.
Too old.

Hah. A Sawzall.
that they do.

[Enzo]

Too big.
Too heavy.
Too old

So you have met my wife then?

[gui_tarzan]

Ouch.

I parted out an M100 last fall and still have the tone wheel assembly if anyone's interested.

[Pdavis68]

So, in a follow up, I ended up buying 3 PA tube amps and a Hammond L101 organ amp (along with the Vibrato & Percussion amps) from the guy for $150.

Now I found someone who's getting rid of a working Conn Caprice organ. I don't think there's any way I'm going to convince my wife to let me bring more old junk home, but this thing looks awesome. Take a look at the back of one. There are over 50 tubes in that upper section, but I don't know what they are. I'm assuming they're 12A_7s. They appear to be that size. I'm not sure if those are transformers or inductors next to them. You can't see it from this angle, but there are two for each tube. One on either side of the tube. The cases that the tubes are in would make decent chassis as well. It's almost too good to pass up.

I may have to sneak it...

[Enzo]

Those are the oscillators, could well be 12AX7s. If you mean the little square aluminum cans with the hole in the end, those are tuned coils. That is how they adjust the oscillator frequency to tune it. Oscillator for each note of the scale, so 12 of those, then they divide the frequencies for the octaves, and those dividers also use tubes.

[DRH1958]

I started out by getting amps from scrapping organs. Most organs of this style did not have 12AX7s for the freq. divider(oscillator) section and I passed on them. A Baldwin I scrapped out had 12AU7s for most of these. I did get some 12aX7s though. Another had 12FQ8s for this function. Another organ I looked at but passed up on didn't have a single 12AX7 in it. You might want to check first. There are other tubes in these that look like the 12a_7 series but are another type. I didn't find much use for 30 12AU7s from the Baldwin and these things are a dime a dozen on the bay. Also, that top chassis is all one piece for the base. They build the tubes and circuitry in sections and mount them on a long chassis. I've given up on scrapping these,it's easier to get the amps off ebay.

[Pdavis68]

Part of the appeal is the price: Free. And the amp in the bottom, alone, would be worth it. Even if the amp is junk, it's got a chassis, transformers, tubes and tube sockets, all the expensive parts of an amp.

I don't know for sure about this model, but I read a similar model has 12AU7s for the oscillators. 50+ 12AU7s is worth a few bucks on e-bay. Not a lot, but it'd be worth the effort.

[DRH1958]

Yep, you can't beat free. It just depends on how much work you want to do. It looks like the main amp has octal preamp tubes. It's really hard to find any free info on the circuits and schematics for these, Conn, Baldwin, etc. It probably has two channels, one for the two main speakers and one for the two smaller ones. Hammond by far has the most info.

[Pdavis68]

Yeah. it looks like I can probably find a schematic on e-bay for about $12. Depending on the shape its in and what the tubes are, it might be better to just gut it and make something completely new with it. Never hurts to have spare chassis and transformers around either... Options, options...