[sdiy] Top Octave Generator (was Chinese MG-1s??!?)

[Tom Wiltshire]

On 1 May 2008, at 16:53, Paul Perry wrote:

> But if one really wants to make a cheap modern MG-1, using a top  
> octave sub
> is not the first thing I'd try to optimize. One really loses a  
> great deal,
> with the lockstep.

I agree entirely. Having twelve separate oscillators is the better  
option for a top octave. The Yamaha organ I have from the 1970s with  
twelve individually tuned oscillators sounds much better than the  
later one that has a TOG.
Oberheim realised this when they made dual DCO synths, and clocked  
the two sets of DCOs from different clocks.

The best way to replace a TOG with PICs would be to use little 8-pin  
chips and use twelve of them!

If that seems like too many chips, pull all the divider chips out as  
well, and then replace the TOG and the dividers by having twelve  
chips that each produce a single note at all required octaves.

> But if one IS going to do it - please use a RF vco for the clock of  
> the
> micro, so one can pitchbend the instrument.

This could also be done with an A/D input and software, but the point  
still stands.

T.