The Warm Audio WA273 is a dual-channel, Class-A microphone preamp designed to provide up to 80 dB of gain for engineers, producers, musicians, and vocalists in mobile-recording rigs and home, project, and commercial studios. It features custom Carnhill transformers and is wired and assembled by hand to deliver the sound and functionality of classic British '73-style preamps. Its inputs include balanced XLR and 1/4" TRS jacks and two front-panel 1/4" TS instrument inputs. Input impedance, polarity, ground lift, and phantom power are switchable. Connect an outboard compressor or equalizer via the 1/4" TS insert send and return jacks. Balanced XLR and 1/4" outputs are fed by output level controls and allow compatibility with most audio interfaces and mixing consoles. The selectable high-pass filter can be set to 50 Hz, 80 Hz, 160 Hz, or 300 Hz for management of unruly bass frequencies. Mic, Line, and Instrument Inputs Insert Sends and Returns Up to 80 dB of Gain Output Level Control Switchable Input Impedance Selectable High-Pass Filter Custom Carnhill Transformers Phantom Power and Polarity Switches Ground-Lift Switch Wired and Assembled by Hand