60’s Tube Organ Tear Down and Recycle

[DSpenceATL]

Hey all,

I’ve got a 1960’s Conn organ that my neighbors put on the curb a few years ago to be carted away to the dump. Of course upon seeing it I couldn’t let that happen and so I dragged it home to the studio. I’ve recently gotten tired of how much space it takes up, realizing that my guitar amps should occupy that prime real estate, given that I’m a guitar player and not an organ player (duh!).

I tried listing it for sale, and after many many price drops, haven’t gotten a shred of interest, so it’s on to plan b. I would like to disassemble this and recycle it into a few projects.

1. The main amp seems a good candidate for a guitar amp up cycle.
2. The internal Leslie and its tube amp would be great to have as a standalone.
3. The foot pedal could be rigged to be a midi controller.
4. The speaker baffling and wood enclosure could probably be used as cabs for the aforementioned, paying homage to the original instrument.
5. The insane number of preamp tubes and transformers on the back must be good for…. Something?

What are your thoughts? How would you approach this? I don’t want to just start tearing stuff apart and lose track of what’s what.
Anything I should be wary of or look out for?

Apologies for the mediocre pictures, not yet in a position to drag it out into the room away from the wall to have a better look.

 

[CJ]

1960's transformers and tubes, sweet!

Those multi can caps are 40 bucks new, they last longer being in the cans,

Lots if nuts and bolts,

Any speakers in there?

I know people who swear by those Hammond organ transformers, they might be the same, check the EIA codes,

 

[shabtek]

does it work? figure out how to patch a preamp/pedal in and use it as guitar amp/ leslie reamp

 

[rock soderstrom]

1960's transformers and tubes, sweet!

Yep, the transformers look very promising. Such organs often have usable speakers and good sounding reverb springs from Gibbs or Accutronics.

Which tube type is used in the sound generation? There are an incredible number of them...

 

[newhall]

What numbers are on the speakers?

 

[Brian Roth]

Are those transformers or inductors being used as part of some type of tone generation?

Bri

 

[trobbins]

The large number of 12AU7 (?) and tunable laminated core inductors are for the master oscillator of each note, and the frequency dividers for each note.

I found that at least half of similar inductors in a Wurl 4100B had suitable inductance (2-4H) and DCR to use as screen and preamp chokes in audio amps - they are tunable, so max inductance is with minimum gap - they may have a tapping, and some may have lower inductance especially if the winding window is only partly filled.

Can you identify the organ model? You may be able to get a schematic/service manual for it to identify power rails - it doesn't look like a 428M or 532, but there were many many models - you could even post photos on The Organ Forum or look through their photos.

 

[hodad]

I have a vague memory of someone on the internet saying there's something kind of unique about the spring reverb tanks Conn used. Regardless, if there's a spring reverb unit in there, it'd definitely be worth keeping & repurposing.

 

[Cqwet Dbdfte]

1960's transformers and tubes, sweet!

Those multi can caps are 40 bucks new, they last longer being in the cans,

"New" was a long time ago, now #1 suspect of being dried out and useless.
Paper and foil caps are 100% suspect.
"Plastic" caps may survive, easy to test for leakage. I'd swap out all those.
Much has improved in caps the last 60 years.
Transformers usually never go bad.
Tubes have longer life than people imagine. Over taxed TV tubes being an exception. Tubes still have value.

 

[DSpenceATL]

pulled it out from the wall this morning and poked around a bit. It’s a Conn Serenade 630 according to the plate on the back.

Speakers seem to be Cleveland Anicos, a 12” and a 15”. Part numbers 58103-2 and 56495 respectively.

Trobbins is correct regarding the 12au7 tubes accompanying these 57013 variable transformers.


*IF* somebody wanted to design some fun preamp or some such utilizing these variable transformers, I would gladly provide them to anybody taking part in the build (while supplies last) - just sayin. I’ve got no ideas for them otherwise.

The Leslie appears to be an Electro Music 10c-2s. This is the part I want to salvage the most carefully, seems a lot of people have had luck rehousing these, but usually without the fast/slow controls etc. since I happen to have the whole thing in tact, I’m assuming it will take not too much effort to just rehouse it as is.

Very interested to check under the hood and see what useful components might be on any boards inside.

 

[DSpenceATL]

Cleared off the top and opened it up, here’s what’s inside.

 

[capacitorless]

IIRC (I've been down this road) you may find some very good preamp tubes in the non-tone-generation sections, both in the amp and in the upper left of the tone generator. The TG is probably full of 12AU7s. Edit: might be RCA clear tops.

The power tubes might be valuable/useful; I can't tell from here what they are of course. I've got two of the Cleveland speakers here; they measure 16 ohms. I'm guessing they're going to sound somewhat like a Jensen P12R.

 

[DSpenceATL]

IIRC (I've been down this road) you may find some very good preamp tubes in the non-tone-generation sections, both in the amp and in the upper left of the tone generator. The TG is probably full of 12AU7s. Edit: might be RCA clear tops.

The power tubes might be valuable/useful; I can't tell from here what they are of course. I've got two of the Cleveland speakers here; they measure 16 ohms. I'm guessing they're going to sound somewhat like a Jensen P12R.

I wonder how easily the amp could be changed to accommodate guitar, and whether the Cleveland 12” would make a decent speaker for a 1x12 combo with that amp..

 

[abbey road d enfer]

I would salvage the power amp, speakers and Leslie, add a preamp, and turn it into a beast of guitar amp.

 

[Cqwet Dbdfte]

... or just keep the whole thing as a room heater for those cold January nights.

 

[capacitorless]

A quick search for the service manual turned up empty.

Based upon the way the speakers are connected and how they ohm out, you could suss the expected impedance of the amp. That said, the transformer looks pretty robust and may handle an impedance mismatch.

There are probably three speakers, the two visible plus the one in the Leslie; probably those are driven by a single output channel, with some form of crossover. It may be a 6L6 pair, cathode biased. One Conn I had came with either 7591s or 7868s.

You could have something usable as a clean guitar amp already. It depends upon what the signal level is going into the amp, of course. It might be a good pedal platform if you don't want to mess with a proper guitar preamp (a single added gain stage might be easy, if you can repurpose a tube socket).

Schematic/service manual would be good; I saw one around $16 on Ebay, so it might be worth the tab if not available free online.

 

[DSpenceATL]

Got everything pulled apart, here are some close-ups of some components I discovered along the way. Do I spy germanium transistors in there? And really tiny subminiature tubes? They almost look like Christmas light bulbs, they’re so little.

 

[trobbins]

Perhaps check how close the Serenade 621 is: https://el34world.com/Forum/index.php?topic=23884.0

 

[Brian Roth]

Got everything pulled apart, here are some close-ups of some components I discovered along the way. Do I spy germanium transistors in there? And really tiny subminiature tubes? They almost look like Christmas light bulbs, they’re so little.

The "tubes" are probably neon lamps used as perhaps a sawtooth oscillator.

https://en.wikipedia.org/wiki/Pearson–Anson_effect

Bri

 

[Brian Roth]

Looking again at the pic showing apparently neon bulbs, I count 12 very similar sections. Top octave generator? But how is it tuned....lol

Bri