<o yeah im talkin about the tube version. could explain what a psu block is? im guessing this is not the same thing as a 48v power supply, and you wouldn't turn on the 48v on your pre.>
PSU=power supply. Unlike solid state devices (which FET is) tubes require two voltages to make them work. High voltage-low current (aka B+, or HT--high tension)--this one for anode of the tube, and low voltage-high current for filament (aka heater). The 48V phantom power would not provide these voltages, or current capability. However, I heard about some mics which work with phantom, but most likely these use special tubes (like some tubes designed for portable radios and have low B+, and low current filaments). You don't need to turn your phantom with GT 1b, however it won't damage your mic if it is on.
