Union Audio four.valve limited 55 Edition

A collectible four.valve, blending vinyl heritage with elara spirit

The Union Audio four.valve Limited 55 Edition pays tribute to analog DJ culture and the connection between turntable, record and mixer. Produced as a unique run of 550 individually numbered units, it retains the four.valve's tube-based architecture while adopting certain aesthetic cues and control elements from the elara and Signature Series ranges.

This edition also features a custom discrete operational amplifier, developed by Andy Rigby-Jones, founder of Union Audio. Its aluminum front panel, knurled controls, gold-colored elements and wooden side panels create a look that coordinates with the limited-edition Technics SL-1210 MK7.

For DJs who put listening and hands-on control first

This rotary DJ mixer is aimed at professionals, vinyl enthusiasts and discerning hi-fi enthusiasts. In a club, studio, listening bar or high-end private installation, it prioritizes level control, smooth transitions and musicality.

The damped rotary controls invite you to create gradual fades, while the Innofader crossfader enables different mixing approaches. Separate Master, Booth and Record outputs make it easy to integrate the mixer with a sound system, booth monitoring and a recording setup.

Expressive tubes and precise signal control

The fully analog audio path preserves the four.valve's sonic character. Driven moderately, the tubes add warmth, depth and harmonic richness. Pushing them harder produces gentle, natural compression—a way to shape the mix's texture and dynamics.

Each channel features phono and line inputs on RCA connectors, a 3-band EQ with a natural response and an auxiliary send. The 3-band Master isolator and adjustable-frequency high-pass filter complete the sound-shaping section. The Send/Return connections and inserts make it possible to integrate external effects processors.

For cue monitoring, the headphone amplifier combines power, Split Cue functionality and a Cue/Mix control. Two headphone sockets accommodate 6.35 mm and 3.5 mm jack plugs. The analog VU meters with phosphorescent finishing complete this interface, designed to maintain a direct connection with the signal.

Technical specifications

Type	Analog	Motorised faders	No
USB stereo recording / playback	No	Line outputs	XLR, Stereo - 6.35mm jacks - Dry signal
Number of faders	4	Headphone output	Mini jack, Jack 6.35

Edition	Limited 55 Edition, celebrating the 55th anniversary of the Technics SL-1200.	Channel high-pass filter with adjustable cutoff frequency	-3 dB at 1,500 Hz at the maximum clockwise position.
3-band Master Isolator	200 Hz / 800 Hz / 2,000 Hz.	Fader shutoff attenuation	greater than 80 dB.