pin1 = B+
pin 2 = heater
pin 3 = pattern
pin 4 = bias
pin 5= audio +
pin 6 = audio -
pin 7 = ground
For the most part, I have settled on this pinout configuration for all new tube microphone builds in the studio for consistency which allows me to place the 2 large gauge wires of the Gotham GAC7 cable that I use on pin 2 (heater) and pin 1 (Ground). The only deviation is on U47 type builds that combine heater and B+ together, I utilize pin 2 for the B+ in those builds so my expensive cables remain interchangeable between all tube microphones.