[sdiy] DAC Recommendation?

[Paul Cunningham]

Hi -- I've been working on a design for hooking up an Arduino to a CEM3394:

http://www.synthtech.com/cem/c3394pdf.pdf

It's a pretty nice analog synth on chip, and I've got extras from a disembodied Sequential Max.

I have a question about doing this, maybe two:

The CEM3394 requires a -4 to +4 CV to control it's theoretical 10 octave range. This chip also requires a -6.5V power source in addition to +5V. I reckon I can work out the power requirements, though I'm still learning about analog circuit design at an amateur level.

The CEM3394 has 8 of these -4/+4 CV inputs that I hope to control using the Arduino. Supposedly I can multiplex a DAC using hold capacitors on these inputs. That seems to be what the Max does.

I'm still mostly focused on learning breadboard style atm, and I would like get everyone's feedback on a modern Arduino-based circuit for controlling the CEM3394. While I hope to settle on something like a 12-bit DAC, there are still many options:

- multichannel DACs
- programmable potentiometers
- SPI vs bus

Oh and how's someone like me, who knows too little yet about op-amp design and voltage scaling, supposed to output a level between -4 and +4 VDC?

Thanks in advance for your ideas -- I have so much to learn about analog! -paul