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RE: [motm] VCDO?

2000-07-17 by David Bivins

FWIW, Paul's previously stated policy has been to set aside one chip for
every installed chip for the out-of-production ones. So you're covered for
at least one mishap ;)

I'd rather see a design using currently available (and hopefully available
long into the future) components, myself.

David.

> -----Original Message-----
> From: Brousseau, Paul E (Paul) [mailto:noise@...]
> Sent: Monday, July 17, 2000 9:44 AM
> To: 'motm@egroups.com'
> Subject: RE: [motm] VCDO?
>
>
> My initial reaction is YES YES YES!  I'd LOVE to play with a waveform
> oscillator.  I don't understand exactly what VC'd morphing means, but it
> sounds interesting.  FM control is necessary, of course.
>
> My only concern is, as Elhardt pointed out, the lifespan of these chips.
> Four thousand seems like a lot, but eventually I suppose that supply will
> run out.  How often do these chips burn out?  Do we need to take any extra
> precautions using them?  Perhaps a backup chip would be a good
> idea?  I know
> I sound paranoid, but...
>
> --PBr
>
>
> > -----Original Message-----
> > From:	Paul Schreiber [SMTP:synth1@...]
> > Sent:	Sunday, July 16, 2000 6:38 PM
> > To:	MOTM listserv
> > Subject:	[motm] VCDO?
> >
> > It just occured to me (well, actually yesterday talking with
> MOTM user in
> > UK) that the 4,000
> > CEM3340s I have sitting here collecting dust could be quickly
> converted to
> > a
> > newer version of
> > the Digisound VCDO.
> >
> > This uses the CEM3340 VCO chip in "ultrasonic" mode (ie say
> 1Khz to 100Khz
> > range) to scan
> > out waveforms in an EPROM. It's pretty easy to have VC'd waveform
> > selection,
> > etc etc a la the
> > Wiard 'Waveform City' (which uses a technique prone to jitter errors).
> >
> > Also cute is Windoze applett to 'draw' waveforms and then
> create Intel hex
> > file to blow into EPROM
> > if you have access to a programmer (like the $129 Needhams one).
> >
> > Anyway, just a thought. Comments?
> >
> > We could get Old Crow to add a PIC to do VC'd morphing (just an
> ADD then a
> > SHIFT before DAC).
> > Or digital GAIN control (0 to +5 goes into ADC on the PIC, with
> a MULT to
> > gain scale. If you don't
> > plug a signal in, there is a 100K pullup to +5 rail into ADC to get
> > full-scale output).
> >
>
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