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).
>