Etherwave Pro and MIDI

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.

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.

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

You need something with functionality similar to this:

http://synthesizers.com/q125.html