[sdiy] Multiple LM317s - serial or parallel?

[David G. Dixon]

> At 3V VCC and 1.25 VRef on the DAC I get an output of exactly 0-2.5V
> (which is a CV source). Running the DAC from 5V and using an op-amp buffer
> to supply the VRef worked-ish - but not as well. The current set up is
> rock solid (so far...).
> 
> At some point the micro that is driving the DAC and reading yhe MIDI input
> is also going to need a supply that isn't my USB port. You're right - I'm
> going to  lot of trouble, it's a pretty ambitious/important project.

Fair enough.  The only time I ever used a DAC, it was a current-sourcing
DAC, so the reference current was determined with a resistor, and an opamp
wired as a current-to-voltage converter on the output gave me the voltage
range I wanted.  However, I'm not familiar with the DAC you're using.  It
just seems like overkill.