Studio Projects VTB1 microphone pre-amplifier - incorporating true class A/B switching, the VTB-1 uses all discrete circuitry. 'Tube Drive' varies the amount of drive to the 12AX7 valve. 48V phantom power, balanced outputs on XLR and 1/4", TRS insert, phase reverse, high pass filter and 5 segment LED metering. Power Supply (Spare Part) #229356
