I build this primarily to use with my Tascam DR-40, since it doesn’t have enough gain for dynamic microphones, and it turned out great. I have couple of boards and components bundled together as a kit. Battery not included.

If anyone is interested, drop me a line.

Op-amp is: AD8648 ARUZ
High Gain about 43dB, set by a trimmer.
Balanced input, unbalanced output.
Very simple, mainly for field use. Very low battery consumption below 6mA.
SNR about 94dB
Trimmers are bottom mouneted now.
Green LED to indicate ON/OFF.