From jackoverfull@gmail.com Sat Jan 19 13:55:27 2013
Subject:Re: Modern Analog Tonewheel Organ Project

Just heard the demos.

A lot of work still to be done but i believe you're on the right track. My congratulations and keep up the good work! Who knows what could happen!

Il giorno 19/gen/2013, alle ore 15.20, donstavely ha scritto:

> Thanks, guys.
>
> Some explanation, Lou: The caps are 0805 size, but the resistors are
> 0603. The real pain is that that they are all different values on the
> tone board, since the 91 filters are individually tuned to their
> respective notes.
>
> I didn't use an ASIC for the tone generation because a) top octave
> chips are all obsolete and hard to get, and b) I want to be absolutely
> faithful to the Hammond note frequencies, not just close to a
> well-tempered scale. So I start with a multiple of the 20Hz main shaft
> and then multiply/divide by each drive/driven gear for each note
> (X85/104 for C, X71/82 for C#, etc.)
>
> The switch board is mainly an array of quad analog switches. The good
> thing is that all the IC's on both boards are cheap and readily
> available parts.
>
> The ribbon cables between the two boards go away - the boards will stack
> together back-to-back. I only wanted them side-by-side for debug. The
> other ribbon cables go away when I do my own MIDI decoder and/or keybed
> matrix interface.
>
> Don
>
> --- In CloneWheel@yahoogroups.com, Lou C wrote:
> >
> > Hi Don,
> >
> > What a cool project! And I can't believe you actually laid out two
> boards for that. But then again you kind of have to when starting from
> the ground up! I can't imagine how much fun you must have had soldering
> all those SMT parts, especially the 0805 components! Oooof.
> >
> > The sound is beautiful! One thing you might try is looking into some
> kind of ASIC that could be programmed to do what you are doing, to
> reduce the number of components. But then again, you probably checked
> into that, too. If you were going into full production of this some
> time in the future, I would recommend looking into an alternative to the
> ribbon cable, maybe a flex circuit?
> >
> > Anyway, nice job! Looking forward to more updates on your progress.
> >
> > Lou
> >
>

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