KaiS wrote on Sun, 06 February 2011 10:27 |
Hello Klaus, I think he wants it the other way round- define an exact resistor value as substitute for the mic. |
Klaus Heyne wrote on Sat, 05 February 2011 17:22 |
...On the B+ side,I would start with a 2W 10KΩ resistor across Pin 5 and ground. trim out until you get ca. 120VDC... |
KaiS wrote on Mon, 07 February 2011 14:16 |
Even then you could replace the tube filament with a resistor for testing. You have to know the current and voltage the tube should be operated at: V / A = Ohm If it's a constant current source AKG used it's limiting the warm-up current to reduce stress on the tube filament, which otherwise draws more current as long as it's cold. I'm not sure if this makes a difference for the tube life, but for sure it doesn't hurt. Regards |