[sdiy] M-Audio Radium CV to MIDI mod

[xamboldt]

I have 2 CV ins right now. Nothing unexpected yet... I've used both  
to simultaneously control separate CCs in softsynths and it works as  
one would expect. I haven't actually used this new feature  
extensively yet - just a little bit here and there. The only weird  
thing so far - I think I mentioned it before - is if I'm not careful  
with plugging and unplugging cables, the circuit will temporarily  
draw too much current and OSX shuts down that USB port. This can be  
avoided but always plugging the cable into the controller first, then  
the CV source. I suppose not using USB host power will also fix that,  
but I haven't dug out an AC adapter for the controller to try that yet.

I'm waiting for my new MIDI to CV unit to show up so I can see how  
effective this set-up will be in allowing me to digitize and play  
back CV sources from a DAW. If it works reasonably well, I'll  
probably expand the controller to a few more CV ins...

-Chris

On Dec 5, 2005, at 9:04 PM, megaohm wrote:

> Yes you're right. I just found those posts. Have you expanded it to  
> multiple CV ins? Have you gotten any interesting/unexpected things  
> out of this mod?
>
> peng
>
>
> On 12/5/05, xamboldt <xamboldt at earthlink.net> wrote: I mentioned  
> doing this to an Evolution MIDI controller a few months
> ago, and I first heard about it on the list quite a few months before
> that in posts by Grant Richter and Larry Hendry.
>
> Anyway, I prevented negative voltage from getting into the circuit
> with a diode routing neg voltages to ground. I don't have any
> positive voltage protection other than the attenuator - although I'd
> like to add something. I was thinking of a zener, but haven't gotten
> around to trying it yet... Has anyone else?
>
> -Chris
>
> On Dec 5, 2005, at 4:06 PM, megaohm wrote:
>
> > I don't remember ever seeing anything about this. But it is such a
> > simple concept I'm sure it's been done.
> >
> >   The Radium's pots have 5 volts on one leg, ground on the opposite
> > leg, and the wiper connects to a 4051. I disconnected the 5V source
> > at the pot and soldered a wire from the 5V pad to the switch of a
> > NC jack. The tip of the jack is wired to the pot leg (the one that
> > was connected to the 5V internal source. With nothing plugged in,
> > the pot acts exactly how it normally did. Pug an envelope in and
> > that becomes the voltage source for the pot.
> >
> >   This should work for any digital stuff that uses voltage divider
> > pots.
> >
> > peng
> >
> >
> >
> > On 12/5/05, Rafael Cohen < rafael.cohen at gmail.com> wrote:
> > I vaguely remember the email on list about this process a while
> > back, but can you remind me how this mod goes?
> > Thanks,
> > Rafael
> >
>
>