Howdy Y'all,
I just came across this posting and even though it is very old, I would like to let you know that there were some errors in the original schematic which have been corrected. It looks like the pics above now reflect the changes I have made on my site.
http://www.wz5q.net/index/shack_data/muneo.htmThe Valves were originally listed backwards. They are as corrected as...
V1 is a 12AX7B used as a Constant Current Draw Amplifier (CCDA) which is using V1a as Grounded Cathode amplifier followed by V1b in a Cathode Follower configuration.
V2 is a 12AU7 used as an impedance matching device.
The factory later added a 2M resister on each Grid on either side of the 510K resistor having an effective 1.113M resistance to ground on each of the Grids.
I had originally transcribed the wrong resistance as 82 ohms for each of the V2 Cathode resistors on the previous schematic. The correct resistance is 820 ohms for each cathode resistor.
The factory lifted the Front Capsule element from chassis ground and added a 51M Resistor in parallel with a .022uf capacitor in between the chassis ground and the Front Element.
The mic works great and has wonderful sonics.
Take Care,
WZ5Q