Roll Your Own Discrete Opamps

Roll Your Own Discrete Opamps by mister Borbely:
http://www.borbelyaudio.com/allfetdac.asp

chrissugar

On this puppy, clearly from a related bloodline of the mic preamp, a couple of comments: The output stage with JFETs at Idss is somewhat questionable since they are already operating at what most consider to be theri maximum current (this is not strictly true as a small positive gate-source for an N-channel will produce even more current before the gate-channel diode starts to seriously turn on).

The other general remark is that if you already have the well-buffered V from the I-V conversion, you can go with filter topologies that minimize input common-mode swing and the associated distortion. Note though that Borbely's cascode desgins minimize this to begin with.

Brad