[HAM] why are tonewheels superior?

[Magnus Enorson]

Phil Glatz wrote:
> So the output is not a pure sine wave? I always heard the Hammond
> system was based on additive synthesis, based on Fourier's analysis 
> of adding multiples of harmonics of a pure tone.  The tonewheel 
> circuitry uses filters to remove harmonics, trying to get as close to 
> harmonic-free fundamentals. And the synchronous motor guarantees an 
> extremely constant frequency.
>
>   
But not a locked and constant phase relationship between the notes, the 
wheels are free to vary in that respect; unlike in the solid-state organs.

> The objective of the tonewheels is to create pure 
> fundamental tones that can be added in various proportions to create 
> more complex sounds.  My question was that since the idea is to 
> create a pure tone to begin with, why should it make a difference how 
> it was created.
>
>   
It doesn't. The evidence is right there in the new B-3 that I had the 
pleasure to play on stage last night - it sounds dead on. But back to 
the older solid state organs:

Problem number one: They do not generate all notes separately. Instead 
they generate high reference notes, and then divide the frequencies down 
to make all octaves of the same note. This causes to the "sinusoidal" 
wave form to deteriorate to the point where it's almost ridiculous.

Problem number two: Up until now with the new B-3, clone organs have not 
had separate key contacts for the individual harmonics of each note. BIG 
BIG issue if you want to make something that sounds like a classic Hammond.

> My question was a theoretical one; assuming the sounds are created 
> with pure tones, why would it matter how they are created?  Are the 
> ones from tonewheels somehow purer - or do they have some slight 
> imperfections that make for a richer sound? Assuming everything else 
> is equal, what difference would you detect if you were to slip some 
> high-quality oscillators in place of a tonewheel generator?
>
>   
My guess is: If you can design a generator that makes 91 individual 
notes, non-phase-interlocked, all the time; by means of good quality 
oscillators - and then install that generator into a classic Hammond, 
utilizing the stock Hammond keying, amps etc, then not many people WOULD 
hear a difference at all.

/Magnus