60’s Tube Organ Tear Down and Recycle

[abbey road d enfer]

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

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

Bri

Indeed they are. The circuit is a frequency divider.

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

They don't need to be tuned, since they follow the master oscillator. Each section is a divide by two. The master oscillator delivers the top octave and the dividers deliver the octaves below.
Master oscillators are apparently tuned by adjusting the nuts on the inductors.

 

[Brian Roth]

I am far from an electronic organ expert, but SOMEWHERE in that Conn is a top octave generator. The card with the neons seemed logical since it had twelve "identical" sections. Just guessing that the portion with the multiple 12AU7 bottles were the octave dividers.

Shrug.....

Bri

 

[zamproject]

What a massive oscillators array !

To me this is not neon tube for octave divider purpose like we can see on Philocorda, but a full 6 octaves single OSC per note.

If you look close this is probably double triode (not neon) with 2 tuning self and 2 oscillator per tube...72 LC single triode oscillators !!! and the back confirm the noval socket

You can also see notes label on the side plate with chromatic pattern and not octaves pattern.

Now it's probably to late...but a restoration is preferable to a tear down... at least that what I'll do if I'll get such instrument, which dose not prevent mod to add preamp and extra input for guitar or whatever to access the amp, speaker and leslie.

If a tear down is mandatory, I'll try to keep the whole OSC section intact, and try to make a crazy drone synth with it !!!
Just imagine the sound of 72 osc with crazy tuning....

 

[bananamoon]

I've had an Estey tube organ given to me that I unfortunately tore down. I wrote to the Estey museum for schematics and never had a response, and from what was working, it sounded pretty much like a hammond. The tubes in these are often quite good mine where 12au7 (amperex D getter buggle boy). I kept all the oscillators and electronics to give to anyone that wanted to make some synth/drone machine with it, but no one wants them. I'dd go with the killer guitar amp idea.

 

[Brian Roth]

Indeed they are. The circuit is a frequency divider.

They don't need to be tuned, since they follow the master oscillator. Each section is a divide by two. The master oscillator delivers the top octave and the dividers deliver the octaves below.
Master oscillators are apparently tuned by adjusting the nuts on the inductors.
View attachment 140476

I was just guessing the last photo in post #17 (with the 12 neon lamps) was the top octave generator and was curious how it was tuned. In the picture above, you pointed to the obvious "tweakers". I had ASSumed that bank of 72 "identical" sections with all the tubes and inductors were the dividers. I guess there are 72 individual oscillators, each requiring tuning. Would be an interesting drone creator, as @zamproject mentions.

My ASSumptions were based on fuzzy memories of how Vox and Farfisa combo organs were designed.

Bri

 

[Brian Roth]

Pic copied from post #17. Those twelve jumbo 1.35 uF white caps puzzle me. Is it possible this circuit is some sort of tremulant generator with one oscillator per note in an octave which is fed to each corresponding note in the generator bank to do AM or FM modulation? A sawtooth wave kinda seems odd.....

As I mentioned, WTF do I know about these beasts! lol

Bri