Warm Audio WA73

Single-Channel Microphone Preamp

The Warm Audio WA73 is a single-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 one front-panel 1/4″ TS instrument input. 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 an output level control 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.

The WA73 is rack-mountable and occupies 1 RU.

• Occupies 1 RU
• Single-channel, Class-A mic preamp wired and assembled by hand
• Created through years of R&D, careful reverse-engineering, and countless hours of auditioning
• Designed to function and sound like a classic ’73-style preamp
• Fully discrete, transformer-balanced signal path
• Custom Carnhill transformers saturate sweetly when pushed
• Tantalum and polystyrene capacitors in the signal path and an output transistor choice that is smooth in high-gain settings
• Stepped mic pre gain
• Inductor-based selectable high-pass filter
• Balanced XLR and 1/4″ inputs and outputs
• Front-panel 1/4″ TS instrument input
• 1/4″ TS insert send and return
• Output control with 5-segment LED meter
• Mic, Line, and Instrument Inputs
• Insert Send and Return
• 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