[sdiy] New to the list

[harry]

Voltage controlled potentiometers can be made with Vactrols
(LED-photoconductor)... Its not a cheap solution, and cannot get
very close to either wiper... OTOH it will go into the circuit
without interaction.

Most controls could be voltage controlled resistors... MUCH easier
to do.

Maybe you don't need ALL controls... just the really useful ones ???

H^) harry

Paul Maddox wrote:

> Stefan,
>
> > I've been lurking the Synth DIY lists for about a week (And going through
> > the archives as well, excellent stuff!)
>
> hello there...
>
> > My Synth background is a little funky, I'm an Electronics Engineer, and
> the
> > reason I studied EE was because I was in love with telecoms and analog
> > synths.
>
> I like the word 'funky' it just doesnt get used enough :-)
>
> > I'm the proud owner of a Minimoog and Micromoog and have been working on a
> > project to build a MIDI to CV converter and rackmounting my mini and
> adding
> > the ability of storing the knob values via MIDI, hence me subscribing to
> > this list.
>
> :-P
> OK, fine way to start, make us all jelous!
>
> > To keep it short (And fire my questions away) I've decided to go for the
> > PAiA implementation of the MIDI to CV controller (Since I'm very familiar
> > with the 8031 and 8051 uControllers), anybody has some words of wisdom?
>
> Ive heard good things and bad things about this midi to CV unit...
> take a look at the one Tony Allgood sells (MidiDAC), its popular and works
> reliably...
>
> > My second question is about my pot to MIDI implementation... I decided to
> > use a second microcontroller for it and use a LINEAR LTC 1851 ADC for the
> > knob A/D (I figured out I needed around 20 ksps per control pot, giving me
> > around 50 inputs once you take the overheads into account, which is far
> more
> > than what I need :) and 2 8091 DAC chips for the preset to voltage
> > conversion... again any words of wisdom or experiences you want to share?
>
> Ok, you're going to have problems with the DACs...
> Look at the schematics, some of the pots arent voltage sources, they are
> resistances (resonance pot is the first one to spring to mind), so you'd
> need to convert the filter to be FULLY voltage controlled...
> Also take a close look at the EGs , I bet they've used resistance rather
> than voltages for some of the parameters.
> What you're planning to do is a MASSIVE task...
> Im sure people here will be able to help though..
>
> > I intend to test this on a fatman kit before trying it with my Moog boards
> > (Which I have already "cloned")
>
> Nice idea, again, compare the filter and EG circuits...
> you big problem is going to be creating a voltage controlled poteniometer...
>
> Paul Maddox
> _______________________________________
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