k brown
Well-known member
With appropriate value subs (gate R up to 1-2 gig and input cap to a typical value), this 2SK170BL circuit is extremely clean as a mic FET. I replaced the circuit in a couple of Oktava 012s, and the mics are much more transparent.
https://www.passdiy.com/project/preamplifiers/b1-buffer-preamp
https://www.passdiy.com/project/preamplifiers/b1-buffer-preamp