Mini organ replica

I've got an old Conn Caprice organ (model 427—with tubes ^_^) that I'd like to replicate, albeit in a more portable form. I have the schematics for the organ and am on good terms with the internal components, but I'm sort of a circuit newbie.

Would it be possible to recreate the circuits involved (each note has its own oscillator) with newer, smaller, cheaper (and probably solid-state) components to create a near-copy of my organ in the size of, say, a Casio keyboard or two?

If needed, I can post the schematics up here... the service manual they came from is over 50 years old.

It can certainly be done.....but if you're a circuit newbie it will be a challenging project!

Alec

Why do you want to do this ? Are you trying to duplicate the sound of the Conn ?

Brevor said:

Why do you want to do this ? Are you trying to duplicate the sound of the Conn ?

Click to expand...

Yeah, basically. I've tried sampling, but that doesn't really capture the full power of the organ (this organ employs an electrodynamic speaker on an oscillator circuit for "acoustic tremolo").

Also, I'll be leaving my organ at home when I go off to college :-( So I want something that'll fit in a closet that has a close enough approximation to the sound of my organ (possibly for gigging) with that analog punch.

It's a very simple organ—only two types of tones: sine and pulse. 36 notes per manual (two manuals) with a 13-note pedalboard. Only a dozen or so stops. And a lovely sustain section (comes close to sounding like a real harp).

I'm really just looking for an answer as to how I can miniaturize the electronics: the caps, the resistors, the tubes (triodes, mostly), and the current involved. Like I said, I can live with solid state replacements for the tubes.

The best way to emulate the sound would be to progam an existing keyboard to a matching sound. Trying to do it in hardware would be folly. Have you looked for emulation support on the organ forum?

https://www.organforum.com/forums/

Yeah, I'm working with NLog synth on my iPad to precisely match the analog parameters, but if it is folly to replicate it in hardware, then call me a fool. Seriously, can it be that hard? There's only two dozen or so caps and resistors per tone generator box. Four busses per tone generator box. Seven (I think) tone generator boxes. It's not matrix keyed, so matching the keys to the generators is easier than falling down. It might be a little tedious, but the basic job of construcing an oscillator circuit should be easy enough. I'm just not that experienced at the math of it.

The auditory nuances of such a system are in the permutations of harmonics, not all of which can be modeled accurately without very serious resources. I don't want to discourage you. I like the idea of a hardware emulation using modern components but I think the result will not come without noticeable compromise in fidelity to the original.

The modularity you describe certainly will make it easier than otherwise. You should put the schematics up, if possible in PDF form.

In the meantime, here's some really good organ playing (classical):
https://www.youtube.com/watch?v=_pY08e_tdtA

KJ6EAD said:

The auditory nuances of such a system are in the permutations of harmonics, not all of which can be modeled accurately without very serious resources. I don't want to discourage you. I like the idea of a hardware emulation using modern components but I think the result will not come without noticeable compromise in fidelity to the original.

The modularity you describe certainly will make it easier than otherwise. You should put the schematics up, if possible in PDF form.

In the meantime, here's some really good organ playing (classical):
https://www.youtube.com/watch?v=_pY08e_tdtA

Click to expand...

Thanks for the link. I'll get right on scanning the schematics.

In the meantime, here are a few pics of the organ in question: https://www.facebook.com/media/set/?set=a.221582241202010.72922.100000507076125&l=f3fe4d8cc9

KJ6EAD said:

The auditory nuances of such a system are in the permutations of harmonics, not all of which can be modeled accurately without very serious resources. I don't want to discourage you. I like the idea of a hardware emulation using modern components but I think the result will not come without noticeable compromise in fidelity to the original.

The modularity you describe certainly will make it easier than otherwise. You should put the schematics up, if possible in PDF form.

In the meantime, here's some really good organ playing (classical):
https://www.youtube.com/watch?v=_pY08e_tdtA

Click to expand...

OK, here's the early schematics (Conn internal): https://www.electro-tech-online.com/members/firepowerforfreedom-albums-conn-427-schematics.html

I also have the finalized schematics from the service manual, but those contain tons of part numbers and illustrations.