Most new Chi-Fi dongle DACs seem to be chasing the same goal: cleaner sound through ever-better chipsets. The MUSE HiFi M3 Ultra takes a different approach, putting a real vacuum tube into a portable DAC. I wanted to hear how that compact design would handle the warmth and resonance associated with tubes, so I was glad to get the chance to try it.
Practical Packaging
The sturdy box contains the DAC and a Type-C to C monocrystalline copper cable for connecting a phone. An iPhone package with a Lightning cable costs an extra $5. The contents are practical rather than lavish, but everything needed to start listening is there. At a competitive price, that’s enough for me.
An Open View of the Tubes
The M3 Ultra doesn’t look like a typical dongle. Its metal housing has an open center that exposes the two military-grade JAN6418 tubes. They’re close enough to touch, although I’d avoid doing so to prevent damage or leaving oil on them. Watching their orange glow is part of the appeal. Physical volume buttons sit along the side, and the absence of a screen suits the stripped-back, old-school design.
Core Specifications in a Small Package
- DAC: ES9028Q2M
- AMP: ES9603Q
- Decoding: 32bit 384kHz / DSD256
- THD+N: 4.4mm 0.0003% (32Ω) / 3.5mm 0.0004% (32Ω)
- SNR: 4.4mm 121dB (32Ω) / 3.5mm 120dB (32Ω)
- Power Output: 4.4mm BAL 480mW (32Ω) / 3.5mm SE 460mW (32Ω)
- Vacuum Tubes: 2x Raytheon JAN6418 (Military direct-heated pentodes)
What surprised me was how close the output ratings are. Single-ended outputs often deliver about half the power of their balanced counterparts. Here, either socket offers enough power to make full-size headphones a realistic option.
First Impressions with Softears Studio4
I started with the Softears Studio4, one of my regular test earphones. The Studio4’s precise, relatively flat presentation made the added tube character easy to appreciate. The sound took on a pleasant warmth, with the sharp ends of treble notes rounded off enough to make extended listening feel comfortable. Voices also gained density through the midrange, bringing an analog texture to the singer’s delivery. There is a trade-off: this pairing moves away from an analytical monitoring sound. Judged as a way to enjoy music, though, I was very happy with the tuning. The appeal was in that fuller vocal texture and gentler top end, rather than a hunt for the cleanest possible presentation.
Pairing with the UM Mest MK2
The UM MEST MK2 pairing was less convincing. The balance between vocals and bass didn’t work as well as I’d hoped. The amplifier’s relatively high 8.6Ω output impedance may play a part, though I can’t say for certain. I wouldn’t want to present that suspicion as a settled explanation. What I can say is that this particular match didn’t give me the same pleasure as the others. With the other earphones I tried, the extra warmth was an addition I enjoyed; here, the vocal and bass balance left me less satisfied.
A Good Match for Planar Headphones
A warm tube amp and a cool, bright planar headphone might seem an unlikely pairing, but this combination turned out to be especially convincing. The soft resonance of the tubes smoothed the sharp, prickly edges of the treble. At the other end of the range, the headphone had the power it needed to give bass notes more substance. Planar drivers can draw a great deal of power, and the 480mW output helped fill out the low-end impact that had sounded hollow. For me, the match worked because the tonal warmth and available drive each addressed a different part of the presentation.
What Kind of Sound Does It Offer?
The internal JAN6418 tubes give the midrange body, texture, and warmth. This isn’t a tuning built around maximum transparency. Its harmonic coloration takes the edge off sharp treble and makes listening more relaxed, while the available power helps demanding headphones deliver convincing bass impact. The attraction is hearing the warmth of an instrument or the breath in a vocal performance, rather than picking a recording apart.
Pros and Cons
Pros
- The most affordable dongle DAC currently available with real tube audio rather than tube simulation.
- Plenty of output power: 460mW through the 3.5mm socket.
- JAN6418 tubes offer military-grade reliability, little heat even after 8 hours, and almost no warm-up time.
Cons
- The physical buttons wobble slightly.
- No display for checking status.
Rediscovering the Joy of Tube DACs
Compared with newer digital gear, the M3 Ultra still has some rough edges. Yet in an audio market so focused on clean measurements, a device with such a definite tonal character has a worthwhile place. A warm-sounding track and the soft glow of tubes in a darkened room can offer a pleasant break for tired ears. That is the attraction here: a different way to enjoy the music, with a character of its own.
One practical tip: an L-shaped USB connector, like the one I use, helps keep the DAC close to the phone instead of leaving it hanging.
Purchase here ↓
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