The Warm Audio WA-MPX is a single-channel tube microphone preamp inspired by the legendary 351-style circuits from the golden era of tape recording. It is designed to move from clean, high-headroom amplification to rich tube saturation, giving microphones, instruments and line-level sources unmistakable analogue character.
High gain with vintage character
Each channel uses a handwired circuit with custom CineMag transformers and three tubes. Engaging High Gain adds an extra 20 dB, taking available gain up to 90 dB — especially useful with low-output dynamic and ribbon microphones.
Key features
- Single-channel tube microphone, line and instrument preamp
- Up to 90 dB of gain with High Gain engaged
- Three-tube signal path with custom CineMag transformers
- Tone switch changes input impedance between 600Ω and 150Ω
- Tape Saturation circuit recreates the tonal filtering of 15 IPS tape
- Switchable 80 Hz high-pass filter
- Switchable 2 kHz low-pass filter for deliberately dark / lo-fi tones
The WA-MPX is suited to tracking vocals, acoustic and electric instruments, ribbon microphones and DI sources, while its saturation and filtering controls also make it useful for adding colour to previously recorded tracks.












