Features Condenser Pressure Gradient Capsule: dual sided gold sputtered membrane Frequency Range: 20Hz / 20kHz Polar Pattern: Omni, Cardioid and Figure 8 with 6 intermediate stages Sensitivity: 13 mV/pa +/- 0.5 dB Description Product Description The R-F-T AR-51 was designed to incorporate the amplifier circuit of the C12 and ELA M 251E into a more affordable package than its Diamond Series counterparts. This circuitry has been a favorite for hi-fidelity stereo pair recordings for decades. TELEFUNKEN Elektroakustik has taken this classic sound and developed the AR-51 Stereo Set. The Stereo Set comes in a custom locking flight case that carries both cables, shock mounts, microphones, wooden boxes, and an American-made dual-channel power supply unit. This newly designed power supply is fully regulated and will power one or both microphones simultaneously, and features a slow-ramping heater voltage to ensure vacuum tube longevity. The AR-51 amplifier uses a New Old Stock (NOS) European-made ECC81 vacuum tube and Haufe T14/1 output transformer, the same major elements as the C12 and ELA M 251E amplifier. Each of these components is rigorously tested in our laboratory prior to installation, and hand-selected for matched pairs. The capsules have matched frequency responses, the tubes have matched gain and noise specs, and the amplifier circuits have matched gain and frequency response. The result is a spectacular sounding microphone with a smooth mid-range, open top end, and a solid, well-balanced low frequency translation. The AR-51's distinct character is great on anything from vocals to drums to acoustic guitar to saxophone.