Warm Audio WA-2MPX Dual-Channel Tube Microphone Preamp

Warm Audio WA-2MPX: A Dual-Channel Tape-Era Tube Preamp

The Warm Audio WA-2MPX is a dual-channel all-tube microphone preamp that authentically reproduces the revered 351-style tape-era design, adding a second channel to the mono WA-MPX. It delivers the lush, dimensional warmth of a tape-machine front end, with up to 90 dB of gain and a handwired circuit built around custom CineMag transformers. Two matched channels make it ideal for stereo tracking, running a pair of microphones, or processing a full stereo mix with vintage tube color. From ultra-clean amplification to rude, saturated character, the WA-2MPX shapes tone with genuine analog controls. This is the tube preamp that gives a recording the sound of a classic tape studio, and one you build a mix around.

How the 351-Style Tube Preamp Colors Sound

A tube preamp amplifies a microphone's signal using vacuum tubes, and as those tubes are driven they add even-order harmonics that the ear perceives as warmth and richness. The WA-2MPX uses three tubes per channel on a handwired circuit, giving it far more of that tube character than a single-tube design. Custom CineMag transformers couple the signal and add the low-end weight and midrange forwardness that defined tape-era recordings. Pushed gently the preamp stays clean and full, and driven hard it saturates into a thick, musical grit. That range from clean to saturated is the whole reason engineers reach for an all-tube pre.

Up to 90 dB of Gain for Ribbons and Dynamics

A high-gain switch adds roughly 20 dB to push the WA-2MPX to as much as 90 dB of total gain, which is an unusually generous amount. That headroom matters because low-output microphones like passive ribbons and vintage-style dynamics need a lot of clean gain to reach a usable level. With 90 dB on tap, the WA-2MPX can drive a quiet ribbon to full level without the hiss that a weaker preamp would introduce. It also means quiet sources and distant miking are well within reach. This gain reserve makes the preamp a natural partner for the exact microphones that most need it.

Tape Saturation and the Impedance Air Switch

The WA-2MPX includes a dedicated Tape Saturation control that emulates the tonal behavior of a 15 IPS tape machine, letting you dial in gentle warmth or heavier, driven color. Tape saturation rounds transients and adds harmonic density, which is why so many records were tracked to tape for its flattering effect. A separate impedance switch moves the input transformer loading between 600 and 150 ohms, adding air and sheen up top, the classic Warm tone move. Together these controls let you go from pristine to vintage-driven without touching a plug-in. It is analog tone shaping at the very front of the chain.

Filters and a Hi-Z Instrument Input

Each channel offers a switchable 80 Hz high-pass filter to clear low-end rumble and a switchable 2 kHz low-pass, or Lo-Fi, filter for creative, telephone-style tones. The high-pass keeps mud and proximity buildup out of vocals and instruments, while the low-pass opens up vintage and effect textures. A Hi-Z instrument input also lets you plug a bass or guitar straight in and record it direct through the tube circuit. That makes the WA-2MPX a color box for instruments as much as a microphone preamp. These practical controls extend its usefulness across an entire session.

Two Channels for Stereo and Beyond

Because it is a dual-channel design, the WA-2MPX can record a stereo microphone pair, track two performers at once, or process the left and right of a stereo mix with matched tube color. Two matched channels of the same preamp keep a stereo image consistent, which a single-channel unit cannot do on its own. That doubles the WA-2MPX's usefulness compared with a mono pre, without the cost or space of two separate boxes. It is equally at home tracking a drum overhead pair or adding tube warmth across a full mix. The second channel is what turns a great preamp into a complete stereo front end.

Who the WA-2MPX Is For

The WA-2MPX is built for engineers who want sultry vocals, woody acoustic guitar, cutting electric guitar, and rich stereo mix-bus color from an all-tube source. First-timers get an enormous jump in warmth and dimension over an interface preamp, with real analog controls to learn on, while veterans get a flexible, high-gain stereo pre for ribbons, dynamics, and mix processing. Reviewers praise its lush tape-era warmth, its abundant gain for low-output mics, and its value as an all-tube dual-channel unit. Whether tracking in stereo or coloring a mix, the WA-2MPX brings the sound of a classic tape studio to a modern room. It is the tube preamp a serious signal chain is built around.