Etherwave Pro and MIDI

Posted: 10/10/2006 6:15:23 PM
chrisransome

From: Australia

Joined: 4/16/2006

Can anyone suggest a way to modify the pitch CV output of my Etherwave Pro (minus 3V to plus 4V) to match the input of my CV - MIDI converter (0v to 5V)? It is damaged by voltages outside this range.

The moog CV mixer at $600 would do the trick, but I was hoping for something much cheaper, that I could make myself if possible.
Posted: 10/11/2006 4:58:13 PM
kkissinger

From: Kansas City, Mo.

Joined: 8/23/2005

Here is a link to some information about using zener diodes to limit voltages...

http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/SoundLabMods.html#PROTECTCVINPUTS

Another method would be to attenuate the voltage to 5v p-to-p and apply a bias voltage to bring the bottom up to 0v.

You could do this with an simple op-amp inverting summer followed by a unity gain inverter.

The summer would attenuate the input cv and add a dc offset. The inverter would "re-invert" the signal. Thus, this is nothing more than a simple op-amp mixer circuit. You should be able to build this for under $10 from Radio Shack parts. (don't know if Radio Shack is in your locale -- any electronic parts retailer should have the parts you need).

Note that by attenuating the control voltage that your voltage-controlled module will no longer track with the Epro's pitch.

Hope this helps.
Posted: 10/12/2006 8:07:20 PM
chrisransome

From: Australia

Joined: 4/16/2006

Thanks, Kevin. I've been fiddling about with various components with vague ideas similar to this in mind with no success - Angelo Fraietta, who makes the CV to MIDI converter is sending me a circuit diagram - if it works I'll make it public here, if not, follow up your ideas.

Chris
Posted: 10/13/2006 11:04:26 PM
kkissinger

From: Kansas City, Mo.

Joined: 8/23/2005

You need something with functionality similar to this:

http://synthesizers.com/q125.html

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