The Bock Audio 47 is a high quality cardioid directivity studio condenser microphone utilizing vacuum tube electronics. Utilizing the U47 format, originally built in the 1950's,this mic takes that platform and expands the electronics bandwidth. It utilizes it's own proprietary cable and power supply. The microphone's audio output is standard male XLR3, with positive excitation of the diaphragm at the front of the mic resulting in a positive voltage at the output XLR's pin 2. Audio output is fully transformer balanced.