Grace Design m501, 1-Channel Mic-Preamp with Ribbon mic mode, Fast and musical transimpedance architecture, Precision audio path with 0.5% precision metal film resistors, New 12 position gold plated rotary gain switch, High performance output line driver amplifier and HPF amplifier, New Ribbon mic mode (also great for dynamic mics) - Relay bypass of phantom power decoupling capacitors, increased input impedance, and 48V lockout, Wide 10-75dB gain range, Enhanced RFI interference suppression, Three output connectors: XLR balanced, TRS balanced and ¼” unbalanced, Bombproof laser-etched black anodized frontpanel, Sealed gold contact relay for Hi-Z input switching, Led indicators for +48V, Ribbon mode, and HPF, Format: API Series 500 Rack