[PolyModular]

[Harry Bissell]

Sounds good to me. I can design (help design) PCB's. That's if Roman Sowa and
I don't argue (hahaha). If Roman is listening... he's probably interested
too....   Harry Bissell



jh <jhaible at primus-online.de> wrote:
No, I have not startet such a project, but for some reason
it starts "knocking at the door of my brain" once again.

I came up with this idea a few years ago, but I didn't 
feel comfortable enough with it back then. But maybe
I do now.

The outline of such a system, as I see it from today's point
of view, would be like this:

(1)

5-Voice polyphonic. What is enough for a Prophet 5 should
be enough for a PolyModular, too.

(2)

No 1/4" jacks for connections, obviously. I still think it
could be done with these old "DIN" HiFi cables (same
connectors as Midi). They are cheap and you can buy
them in various lengths - no soldering of cables required.
They are sturdy enough for studio use at least. They
have 5 pins for 5 voices, plus a shield.

(3)

Every potentiometer in a "normal" modular would have to be 
replaced with 5 VCAs. This used to be frightening for me
back then, but it isn't any longer. We can learn a lot from
these Korg PS synths. What they were able to do with full
polyphony should be possible for a 5-voice stem, too.
Yes, 3-transistor filters, and single transitors or even diodes
for certain VCA functions. And EMS used a single FET 
for the VC resonance of their diode ladder filter...

(4) 

Mixed linear / exponential VCOs. Another thing to learn
from Korg, MS series this time. Make the keyboard CV
linear (V/Hz), and do the exponential modulations with
a non-tempco exponential multiplier. And I don't see any
reason why the Emu / Oberheim keyboard circuit shouldn't
work with exponential D/A conversion as well !
No Autotune required then. What is possible in a CS-60 ...
you get the idea (;->)

I really start feeling excited. It will be possible, and it will not
be much more expensive than a monophonic system.
I probably cannot build such a thing all alone. With everything
in a module x5 pcb's would be crucial - no veroboard here.
But do a *small* circuit once, and just copy and paste.

No idea if I get such a project off the ground, but the 
tempting thought is that the *really* expensive things of
a modular, i.e. front panels and potentiometers, are the
same as in a monophonic system.

So the question is: Are more people interested ?
I think I could manage to come up with the *circuits* for all the
basic modules within one year or so. Is there someone who
could do the pcb part ? (Of course there is the possibility
for everybody to add special modules, but 

Once again: at the moment it is no more than checking an idea.
I don't know if I ever find the time. But then again, I can
hardly stop building (addiction ....), but such a system
would possibly be the only thing I'm really interested in at the
moment.

What do you think ?

JH.


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