Organ amp guitar conversion

[Structo]

I converted a M3 amp.
It had a 5U4GB, 2x 6V6 and a couple 12ax7.

The recto, power tubes and 12ax7 were all from the 50's and work to this day.

It ended up being a 6V6 Rocket.

[Crossfire]

Still up in the air on this. Really tight wiring in this old organ, I think there's a lot of great parts in this thing

[Baxtercat]

Picture number three shows the output transformer lower left corner. I have that same chassis and haven't thrown it away yet.

Me too...continually cannibalizing it for little components. In fact I just was in there again yesterday for some resistors I needed.

[Crossfire]

Would love to hear what one of these would sound like converted into an amp. Put a reverb unit on it and turn it up.

[Cygnus X1]

Crossfire we exchanged about 50 PM's thinking about trading something for something.
I apologize here in public for I was not able to carry forward with the 7 watt we were discussing.

From the seed comes growth.
Now there are exactly 7 amps on my bench in process and some in the mail coming to me for work.

Many blessings have ensued, and I know yours will abound.

With or without me!

[Crossfire]

It is quite ok my brother. I've went with fender as my main amp now, but I would still love a low wattage hand wired champ clone. That would be really great. Glad to hear your business is well. God is good!!!

[Luthierwnc]

I've gutted lots of organ amps into guitar amps. They don't always work out but I'm not in it for the money. The power transformers are often bigger than you need because they may have run lots of preamp tubes -- sometimes on auxiliary chassis. The silver PTs in the M-series Hammonds were made for a pair of 6V6s but they will run 6L6s at 450 volts (SS rectified) and not even get warm. The older black versions are good too.

The weak link is usually the output transformer. Just going by the weight test they come in lower than a Fender equivalent. Unless you know better, expect less low end than the amp you are replicating. They also usually only have one output tap so plan your speakers accordingly. Another drawback can be the chassis shape. My better efforts have been with the long Hammonds or Thomas organs because there is room for the complicated preamp sections we use.

I've tried spot cleaning and checking but in the end I gutted and replaced everything. That way you can also get rid of the smell they all seem to have and burnish out the mouse piss. Spend a little time thinking how you will attach the chassis to the cab. Grinding the outward flange is a pain. My better efforts have had a Vox/Matchless type front panel with enough wood on the sides of the front panel to hide the mounts. You can use clip-on nuts but they lower the top leading edge visibly so plan to shim in a decorative 1/4" molding under the top to mask it.

I've attached a picture of an "M" Hammond that became a T-Lite (search this forum and the Hoffman site for much more detail on this worthwhile project -- thanks 10th Tx). You can see there are 1/2" firring strips to flush out the sides. This is the amp that used the side-mounted shock absorbers on this thread:

https://tubeamparchive.com/viewtopic.ph ... unt#203872

It is actually blonde but the camera makes it look yellow. I used a sharp-cutoff pentode and wanted to keep the combo mambo away from those delicate rods.

Good luck giving those lonely amps new homes, sh

[Diablo1]

I just gutted my first organ, a Hammond E-100, and boy does that have some useful parts in it. I won't reuse the chassis, because I have another source for a custom chassis to my specs. Great PT, with 6A capable on the 6.3V heaters, 2A@5V for the rectifier, bias taps, and enough current on the HT for two fixed bias 7591 output tubes (around 45 watts output) at 450 volts on the plates. The PT also has a lower voltage secondary winding that operates the reverb power amp (push pull 6GW8s) with 325 volts to the plates. The OT should also be good for 45 watts. The reverb section OT should also be good for a little amp by itself.

[Crossfire]

FYI, all contents and components are still up for trade

[Diablo1]

The disease continues. I picked up a Hammond PR40 tone cabinet, which yields good speakers, tubes and transformers. Also got a bare Hammond AO-29 chassis, and that PT should make a great 5E3.

[Crossfire]

Plenty of nice parts in there

[Diablo1]

Today, I picked up an AO-68 amp. I'm not sure what organ model it came out of, and I can't find the schematic, but I like the parts. If anyone has any info, I'm all ears.

[Structo]

This is supposedly a AO-28