the problem I wish to resolve is 1) DAC 8 bits not enough to get resolution of 0.11 V / note between -12 V and 3.6! 2) -12V is the inactive state, shurely it would be easiest to switch between it and the "note-on" voltage in hardware, rather than getting a DAC with more bits...I have looked at the CMOS 4016 and 4066 and decided that yes, this may suit my purpose, with -7.5 V and 0 V as inputs, so the analog output siganl becomes the sumation of voltages from the DAC and 4066. Is this a correct interpretation?