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

[Mike I]

Another really nasty thing about the TOG + divider approach is that there is
unwanted signal coupling  from all the oscillators and dividers running
continuously, sometimes a noise gate is used to shut off the output to hide
this. Adding the ability to mute outputs that aren't currently in use would
be a good idea, or even just a simple global "mute all" signal.
M.

----- Original Message -----
From: Tom Wiltshire <tom at electricdruid.net>
To: Paul Perry <pfperry at melbpc.org.au>
Cc: <Synth-diy at dropmix.xs4all.nl>
Sent: Thursday, May 01, 2008 5:47 PM
Subject: Re: [sdiy] Top Octave Generator (was Chinese MG-1s??!?)


>
> 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.
>
>
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