Has anyone built an amp from an old Hammond organ?

[crgtr]

I have my grandfathers M3 organ. 6V6's and other assorted weird little tubes in there. This weekend I found another one in a thrift store for $25. I stripped them both including the speakers. My goal is to pay tribute to my grandfather and have an amp built from his old Hammond and try to use the speaker & grill. I even pulled the toggle switches and a ton of very old & large caps.
So....am I insane or can this be done with a good outcome?
I'm hope so. It would be a great tribute to a great man.
thanks in advance.

[Colossal]

Lots of guys repurpose organ parts (sounds kind of medical and creepy when I put it that way) for guitar amp builds. Search here on AO-35. MFowler and others have converted these amps into Carmen Ghias, 18W Lite IIbs, etc. You'll be well positioned with your parts on hand for an economical and probably a great sounding amp. Some fantastic tubes and components can come out of these old organs.

My grandma and grandpa had a badass old Baldwin and a Leslie which I would have loved to have today. My grandma could rip out a rendition of Under The Double Eagle that could turn a hippie Republican. Great memories of them.

Good luck with your project.

[crgtr]

Lots of guys repurpose organ parts (sounds kind of medical and creepy when I put it that way) for guitar amp builds. Search here on AO-35. MFowler and others have converted these amps into Carmen Ghias, 18W Lite IIbs, etc. You'll be well positioned with your parts on hand for an economical and probably a great sounding amp. Some fantastic tubes and components can come out of these old organs.

My grandma and grandpa had a badass old Baldwin and a Leslie which I would have loved to have today. My grandma could rip out a rendition of Under The Double Eagle that could turn a hippie Republican. Great memories of them.

Good luck with your project.

Thanks! I've heard some pretty cool ones on YouTube. I just thought it would be a great tribute to my grandpa. I restored hi 100 year old fiddle a few years back & it sounds awesome....well, when someone who can PLAY plays it!.
I'm hoping to use as much of the original as possible. Try not to copy a specific amp. Just kinda see what happens.

[Structo]

I did it and if given a second choice I wouldn't have.

I wanted to use as much of the old amp as I could but after looking at it the only thing I kept was the power transformer and rectifier socket and tube.

It has gone through several renditions but what it ended up was a 6V6 Rocket.

I ended up shortening the long chassis (probably too much).

The photo of the conversion is a Deluxe type amp that didn't live long before converting to the Rocket circuit.

One problem was the power transformer put out a lot of voltage that I had to drop to a usable value.
I used a 25 watt Zener stud mount diode to drop 25v.
You can see the diode just to the left of the power transformer.
It has a small orange drop cap to quench any noise.

If yours is a AO-29 amp (which is sometime stamped on the chassis exterior) then it might have the 380-0-380 power transformer like mine.
These amps used a field coil speaker, which preceded the permanent magnet type speakers.
They used the field coil as a choke for the power supply.

You may have to drop some voltage.

[Structo]

This is how the amp ended up.

[Phil_S]

Whether you will be successful in converting to a guitar amp depends a whole lot on the suitability of the transformers for the amp you want to create. If you don't have experience building tube amps, even if you have a good match of transformers to the project, it is going to be challenging.

[Colossal]

This is how the amp ended up.

Crammage!

[crgtr]

Thanks guys. I have no building experience. Gotta start somewhere!! I do have some friends here in town that have offered to help me get started. No telling what I'll end up with, but I think I'll have fun with it regardless. I'll post some updates when things get rolling.
Going thru a divorce right now so funds are extremely limited. It'll be a little while before I can dive into it full-bore. I just hope the Big "D" will be final SOON!!! Lawyers are too damn $$!

[rdjones]

Tube type Hammond organs can provide a decent source for parts including tubes, chassis, vintage caps (if you like reusing caps) and especially transformers (not to be confused with Hammond of Canada transformers, also good for different reasons).

I used an organ output transformer (pretty sure it was from a Hammond) for a Fender Deluxe Reverb rebuild.
The size, shape, appearance and specs were all nearly identical to the OEM Woodward - Schumacher.
Power transformers are usually pretty beefy as Tom shows in his posted photos.
Part of the reason behind this is the organs have a lot more preamp and tone generating tubes than a typical guitar amp so the filament current capacity will be proportionately higher than the HT.

Post back with more about what you may be interested in doing, lot's of us here are scavengers and it's quite fun to find cool old parts for projects.

rd

[sdorer]

If the organ amp uses miniature preamp tubes then the transformer will work fine for a guitar amp. I have used the transformers with great success. If the tubes are all octal then you have the field coil speaker type and the voltages are too high.

[crgtr]

If the organ amp uses miniature preamp tubes then the transformer will work fine for a guitar amp. I have used the transformers with great success. If the tubes are all octal then you have the field coil speaker type and the voltages are too high.

The organ amp has mostly 12au7, ax7, 6v6's and a few smaller tubes. All tube sockets have the tube type stamped into the metal chassis. I wish they would all do that. I had some friends with lots of experience look yesterday & they think it'll be a cool project. They also dated my speaker, which is an AlNico Rola from '56. And it's in great shape. I'm very excited about this amp. Gonna call it the Hubert in honor of my grand dad.

[Cygnus X1]

I've been repurposing organ amps for a few years now.
Every time I test a power transformer from one it scares the crap out of me unloaded, but somehow when I get everything together and running...the voltages are usually close to what I can work with, without dropping zeners and whatnot.

I've found great OT's as mentioned.
I'm afraid all the prototyping I do with organ iron will not translate very well when I have to purchase them.
I should hold some back to get them reproduced, custom made.

I have the exact same M3 waiting for a plan at the moment.
I've already scavanged another M3 and used the OT for a high gain 6V6GT pair build.
Sounds great!

[pullshocks]

Structo--I have one like yours that I have never done anything with due to the high voltage.....curious why you did not try the original OT? Does its original use with field coil speaker make it unsuitable for permanent magnet speakers?

[guitardude57]

The field coil was a handy way to have a choke. A regular speaker
will work fine plugged into the speaker jack.
2 separate connections there. One DC, (field coil) and the speaker, AC voltage.

[M Fowler]

I like to just buy the Hammond organ power supply chassis it has the PT and rectifier tube. I test the HT and mark that on the PT. Since most are prefect for PP 6V6 and PP 6L6 HT ratings I use the PT's to build Fender type circuits.

The tone I get is great, no over heating from these great old PT's. I've bought two complete organs before and it's a waste of time as the caps are not useful and very few CC resistors have long enough leads to use.

Mark