POST DATE : 27 April 2026
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WRITTEN BY : Hemant Khatri
Rotary mixers have always sat somewhere between hi-fi listening and DJ performance. Lately, that gap has started to close again, with more DJs leaning towards sound quality and longer, more patient mixes over feature-heavy setups.
For a long time, rotary mixers were tied to a certain kind of sound, warm, full, and forgiving. They shaped the early days of DJing, then slowly disappeared as digital gear took over. Their return has largely come from house and techno DJs, where the focus is less on quick transitions and more on how tracks sit together over time.
The Union Audio Two Valve Rotary fits right into this shift. It’s a compact 2-channel mixer built around a fully analog signal path, with tube stages, a 3-band isolator, high-pass filters, and just enough flexibility without overcomplicating things.
It also carries some serious legacy. Andy Rigby-Jones, known for his work on the Xone series and Richie Hawtin’s Model 1, founded Union Audio in 2014. The earlier versions came with the MasterSounds branding and since Ryan Shaw’s(founder of MasterSounds) exit in 2024, the brand has become a more focused outlet for Rigby-Jones’ approach to analog mixer design.
This is very much a mixer built around sound and feel. After spending a few weeks with it, that focus becomes pretty clear. Here’s what i think of it so far.
Design & Build Quality
The build and overall feel of the mixer is quite robust and somewhat reminiscent of the MasterSounds Two Valve Rotary MK2, except for the black design of the MK1. The mixer features a full metal chassis and weighs around 3.5 kg. In terms of size, it’s a fairly compact rotary mixer and easy to carry around for shows. The overall design feels simple yet effective, making it easy for anyone to understand how it works. The rotary faders feel smooth in operation with a satisfying resistance. Despite being compact, the spacing between the knobs is well thought out and allows for quick adjustments without feeling crowded.
The mixer provides dual phono/line inputs per channel, a crossfader, 3-band EQ for each channel, a 3-band isolator, trim knobs, FX send, cue mix, and a high-pass filter on both channels. The phono inputs come with high-quality RIAA equalization accurate to +/-1 dB from 20 Hz to 20 kHz.
Not very common in modern rotary mixers, the crossfader does open up creative possibilities when mixing two channels. I personally didn’t find myself reaching for it often, but it’s good to have the option for different styles of transitions or performance in the future.
The stereo VU meters on the top right add a lot of character to the overall visual identity while also being functional. The lighting is warm and turns red when the channel starts to peak.
Having used quite a few rotary mixers, for me personally, the cue button on this mixer was one of the most satisfying to use. It’s in these small details where the quality of the mixer becomes more noticeable.
Overall, the design is simple and effective, and portability is another area where the mixer performs well.
The mixer comes with a standard power supply, with an option to upgrade to the mix.R PSU unit. I tried both, and I would recommend investing in the mix.R only for more professional setups. The mix.R is a premium linear power supply that helps reduce unwanted hum or noise and includes an advanced voltage regulator. If these issues are common in your setup, the upgrade might be worth considering.
Tech specs:
Inputs
Dual RCA stereo inputs per channel
Switchable phono/line input support
Integrated RIAA phono preamp (±1 dB accuracy, 20 Hz–20 kHz)
Filters & Isolator
Per-channel High-Pass Filter (HPF)
-3 dB point at 1500 Hz (fully clockwise)
Designed for low-end rumble reduction
No Q control (fixed curve for simplified operation)
3-band master isolator
Frequency bands: 200 Hz (low), 800 Hz (mid), 2000 Hz (high)
Full cut to +6 dB boost per band
FX Send/Return
Per-channel aux send
Switchable pre/post fader
Stereo FX return path
Dedicated return level control
Supports external effects processors via insert routing
Monitoring Section
Dedicated cue/monitoring section
Signal Path & Sound Character
Talking about the signal path and sound character, this is where the mixer clearly shines. The mixer features a fully analog signal path, maintaining full analog integrity without any digital processing. The two valve (tube) amps add even-order harmonics and subtle saturation. The valves are known for their “warmth,” natural compression, and smooth, musical distortion when pushed, without adding muddiness. I found the output to be quite sonically pleasant, with a good sense of clarity. An important thing to note is that there is no option to change the valves in the future.
While the low end feels slightly rounded, allowing for smoother and more musical blends, it is still controlled enough to carry the punch a house or techno DJ would expect. The midrange feels clear and lush, while the highs come across as smooth and wide.
Even when I was cranking up the levels or pushing the EQs, there was enough headroom (+27 dBu max, 116 dB dynamic range, 0.1% THD+N) before things started to sound distorted or unpleasant. The isolators on the other hand sound clean and offer a complete kill option.
As a house and techno DJ, and having used multiple rotary mixers while being familiar with the AlphaTheta and Xone ecosystem, the high-pass filter is an important part of my mixing technique. While it is often absent in modern rotary mixers, the Two Valve does include an HPF, and I must say it might be one of the cleanest I have used. Even when pushing the filter to higher levels, it still sounds pleasant and allows for building tension, which wouldn’t be possible with just the isolators. In terms of behaviour, the HPF feels quite natural till around the 11 o’clock position without filtering too aggressively, and beyond that it starts adding a noticeable resonance.
Overall, I was quite impressed with the tonal profile and how the mixer sounds. You know its in these small details Features like the high-pass filter and the implementation of the tube amps give confidence that the makers have paid close attention to detail and considered different use cases, not just for hi-fi enthusiasts but also for DJs and their modern workflows.
Workflow & Real-World Use
I tried out the mixer for over two weeks, spending hours mixing records. Rotary mixers, in general, excel at long blends, especially for house, disco, or techno. Layering multiple tracks also felt like a breeze. The valves add subtle saturation, and the summing naturally glues everything together, resulting in a much warmer and cleaner mix. As a house and techno DJ, I really enjoyed the unit, and it allowed the records to sound the way they are supposed to.
With that said, it’s not for controller or laptop DJs who rely on USB, FX, or loops, fast scratch genres like hip-hop or DnB (despite the crossfader), or budget-conscious users.
When compared to mixers like the Xone:92, which offer a more clinical, precise, and neutral sound designed for club reliability and transparency, the Union Audio Two Valve Rotary sounds comparatively warmer, more tube-inflected, and leans towards musicality over transparency. Compared to mixers like Condesa, which offer a more vintage-style character, this feels slightly less coloured and relatively more neutral.
To give you a better idea, It sits somewhere in between, warmer and more musical than a Xone:92, but more controlled and less coloured than something like a Condesa.
What I liked
Warm, tube-inflected tone
Low THD+N (~0.1%) with wide frequency response (20 Hz–50 kHz ±1 dB)
Hand-built, robust chassis with premium components
High-quality rotary faders and crossfader (Innofader compatible) with solid, “no-plastic” feel
High dynamic range (~116 dB) and strong output (+27 dBu) suitable for club and hi-fi systems
Tube stages add subtle harmonic enhancement and perceived depth to playback
What I didn’t
Price: Premium/boutique pricing (~$1,500)
Limited features: No onboard FX
Verdict & Who’s It For
The Union Audio Two Valve Rotary definitely prioritises sound above everything else, and it delivers on that promise. The fully analog signal path combined with tube amplification results in a mix that feels rich, cohesive, and naturally musical without ever sounding overly coloured or muddy.
What stands out is how easy it is to work with longer transitions. The headroom, clean isolators, and well-tuned high-pass filter make it a great choice for vinyl DJ use.
That said, this is not a feature-driven mixer. You’re paying for sound and build quality, not flexibility. At its price point, it sits in a very specific space, warmer and more musical than something like a Xone:92, but more controlled and less coloured than boutique options like Condesa.
If your priority is how your records sound and feel in a mix, this is an easy recommendation. If not, there are more practical options available.
A massive thanks to Sound Redefined, New Delhi for providing the demo unit for review purposes.