I Didn’t Expect Much From the Muse HiFi M7. I Was Wrong. This is most interesting device this year!
The Purple Box That Wants You to Open It
Hi-fi has a uniform. Black or silver. Brushed aluminium. A big knob, a small display, and a press photo shot on a moody wooden desk.
The Muse HiFi M7 Player showed up wearing purple.
Not a shy, "available in three colours" purple either. A deep, metallic, anodised purple that covers the chassis, the case, the circuit board inside, and even the manual. It's loud. It's a little ridiculous. And honestly? I fell for it the moment it came out of the box.
Because the M7 doesn't look like a hi-fi product trying to look expensive. It looks like an object someone actually designed. Machined edges, a gold knurled knob, a glass lid, and a colour that tells every hi-fi cliché to go sit in the corner. It's closer to an art piece than a gadget, and I mean that as a compliment.
But the colour isn't the real reason I love it.
The real party trick is that you can open it
Lift the glass lid. No screwdriver. No heat gun. No YouTube tutorial. Four magnets hold it in place, and underneath you'll find a battery you can swap in seconds, two op-amps sitting in sockets waiting to be rolled, and four tiny vacuum tubes glowing away.
Remember when this was normal? When your laptop had a battery latch and your phone had a back cover you could pop off with a fingernail? Somewhere along the way, the industry decided that glue, proprietary screws and parts locked to a single device were "premium". Today, replacing a battery in some phones can mean warning messages, disabled features, or a repair that costs a scary chunk of the phone's price.
That's exactly what the Right to Repair movement fights against: planned obsolescence, and devices built to be replaced instead of fixed. People like Louis Rossmann and Zack Nelson of JerryRigEverything have spent years tearing gadgets apart on camera and pushing for products that you, or any independent repair shop, can actually fix. I applaud every one of them. And the EU is pushing in the same direction, with battery rules that will require replaceable batteries in portable devices from 2027.
So when a $399 portable DAC/amp shows up with a tool-free lid and a standard 18650 battery, I don't just see a feature.
I see a statement.
A lithium cell is a consumable. Five or six years from now, the battery inside every sealed DAC/amp will be tired, and most of those devices will end up in a drawer or a bin. The M7's battery costs a few euros and takes ten seconds to replace. That alone could double its useful life.
Is that enough to forgive everything else? Let's find out.
Specs: A Spec Sheet That Reads Like a Dare
Four tubes, an ESS flagship-class chip and 3.5 watts, in something you're supposed to call portable.
Spec | Muse HiFi M7 Player |
Price | $399.99 |
DAC | ESS ES9039Q2M, with 2x ES9603Q I/V and 2x ES9603Q low-pass chips |
Tube stage | 4x JAN6418 subminiature pentodes, fully balanced (two per channel) |
Op-amps | 12 in total; 2x socketed MUSES01, user-swappable |
Modes | VT (tube) and TM (transistor) |
Output power | 1,750mW (3.5mm), 3,500mW (4.4mm balanced), into 32Ω |
SNR | 124dB (3.5mm), 128dB (4.4mm) |
Inputs | USB-C, Bluetooth 5.4 (Qualcomm QCC3095, aptX Lossless) |
Outputs | 3.5mm single-ended, 4.4mm balanced |
Gain / filters | 3 gain levels, 8 digital filters |
Battery | User-replaceable 18650, 3,500mAh |
Claimed battery life | Up to 20 hours (TM), up to 15 hours (VT) |
External power | 12V DC input, bypasses the battery ("DualRail") |
Extras | Built-in microphone for calls, sleep timer, purple leather case |
Gorgeous, Solid, and Absolutely Not Pocket-Sized
Pick up the M7 and the first word that comes to mind is "dense".
The chassis is CNC-machined aluminium with chamfered corners and a deep anodised finish. Top and bottom are glass. The gold volume knob is knurled and feels great under your thumb. Nothing creaks, nothing rattles, nothing feels cheap. For $399, the fit and finish is genuinely excellent, and the matching purple leather case is a nice bonus rather than an afterthought.
But "portable" is doing some heavy lifting here
Yes, it runs on a battery. Yes, technically, you can carry it around. Technically, I can also carry a microwave around.
The M7 is the biggest and heaviest thing Muse has made in this series. It's the size of a chunky power bank, and once you add a phone, a cable and headphones, you've built yourself a small sandwich of electronics. It won't disappear into a jeans pocket. A jacket pocket, maybe, if you enjoy one side of your coat sagging.
Where it actually makes sense is around the house. Desk to sofa. Sofa to bed. Bed to balcony. Think of it as "movable hi-fi" rather than "portable hi-fi", and suddenly the size makes a lot more sense.
And then there's the name
M7 Player.
Is it a player? No. It has no storage, no streaming app, no operating system, no way to play anything by itself. It's a DAC and headphone amplifier that needs a phone or a computer to feed it music.
Yes, you can pair it over Bluetooth. Yes, the side buttons skip tracks, so you can jump through a Tidal playlist on your laptop without touching it. But skipping tracks on someone else's playback doesn't make you a player, and play/pause is buried behind a long-press of the Menu button that you'll trigger by accident more often than on purpose.
Calling this a "Player" is marketing, plain and simple. It sets an expectation the product can't meet, and it confuses exactly the people who'd love it most. Muse, you built something genuinely interesting. You don't need to oversell it.
Features: Simple Menus, Serious Hardware
The M7 keeps things refreshingly simple. One Menu button cycles through everything, and the small screen up top shows what you've picked.
Two amps in one box
The headline feature is the mode switch. VT (vacuum tube) routes the signal through the four JAN6418 tubes. TM (transistor) bypasses them entirely and runs a pure solid-state path. Two different characters, one device, and you can flip between them in a couple of button presses. Why "VT" and "TM" instead of just "Tube" and "Solid"? No idea. You'll learn it, but nobody gets it right the first time.
Gain, filters and a sleep timer
Three gain levels (low, mid, high) cover everything from sensitive IEMs to hungry planars. There are eight digital filters too, and I'll be honest: the differences between them are subtle at best. Pick one and move on with your life. The tube-versus-transistor switch changes the sound far more than any filter ever will.
There's also a sleep timer from 10 to 60 minutes, which tells you exactly where Muse expects this thing to live. In bed. With you. Falling asleep to an album.
Bluetooth that's better than your phone
The Qualcomm QCC3095 chip supports Bluetooth 5.4 and aptX Lossless, which can send CD-quality audio without losing data. The catch: your phone needs to support it too, and iPhones and Samsung Galaxy phones don't. A Snapdragon chip alone doesn't guarantee it either. With my phone, USB still sounded clearly cleaner and more detailed than Bluetooth, so check your phone's codec support before buying for wireless use.
DualRail: battery on the go, 12V at the desk
Plug in the included 12V adapter and the M7 stops using its battery entirely and runs straight from the wall. That's great for battery lifespan and turns the M7 into a proper desktop unit. Two things to know, though. The 12V input doesn't charge the battery; that's the job of the separate USB-C charging port. And switching between battery and DC power shuts the M7 off, so there's no seamless handover.
Connections
USB-C for audio, a separate USB-C for charging, the 12V DC input, plus 3.5mm and 4.4mm headphone outputs. Everything sits on one edge of the device. For what it does, that's enough. But for a box this size, I'd have loved a little more, which I'll get to later.
And yes, there's a microphone
The M7 has a built-in mic, so you can take calls through your wired headphones over both Bluetooth and USB. Handy. Just know that the leather case covers the mic hole, so callers will hear you a bit muffled.
Battery life
Muse claims up to 20 hours in transistor mode and up to 15 in tube mode. In my testing I got comfortable 12 hours, which is great for this kind of movable hifi.
Premium Where You Hear It, DIY Where You See It
Since Muse lets you lift the lid, let's actually look inside. What's in there, how good is it, and what can you upgrade?
The op-amps: properly premium
Those two chips in sockets are MUSES01 op-amps from Nisshinbo, the Japanese company formerly known as New JRC. They're J-FET input dual op-amps and among the more expensive audio op-amps you can buy. Muse didn't cheap out here. Yes, the brand called Muse uses MUSES op-amps. I see what you did there.
Because they're socketed, you can swap them. Muse lists the OPA2134 and LME49720 as compatible, and both are classic choices: the OPA2134 leans smooth and forgiving, the LME49720 cleaner and more analytical. If you want to go further, discrete op-amps like Sparkos Labs or Burson's V6 series are the big upgrade. They're tiny hand-built amplifier modules instead of a single chip, and there's plenty of room under the lid for their taller bodies.
A few rules before you start rolling:
Power it off first. The board literally says so, in big print, right next to the sockets.
Buy the dual version. The stock chips are dual op-amps, and most discrete makers sell single and dual variants. Get the wrong one and it simply won't work.
Mind the notch. Match the orientation marker on the chip with the socket.
Skip the included tweezers. They're sharp and fine-tipped, not made for pulling chips. A cheap IC extractor tool does the job safely.
Expect a battery hit with discretes. They usually draw more current than the stock chips, so battery life will likely drop.
The tubes: real, but married to the board
Four JAN6418 subminiature pentodes lie flat in the middle of the board, held down by a screwed metal clamp bar. The JAN6418 goes all the way back to the early 1960s, designed for small, battery-powered equipment that needed tubes sipping as little power as possible. That's exactly why it works so well in a portable today.
The catch: their wire leads are soldered straight to the board. So no tube rolling, and if one ever gets noisy, it's a repair job, not a five-minute swap. Ironic, in a device this proud of being modular. A small plug-in tube socket would have completed the story.
The battery: a legit cell, easy to replace
Inside is an EVE INR18650-35V, 3,500mAh. EVE is a big, established cell manufacturer, so this is a proper branded cell, not a mystery battery. A fabric pull-tab makes removal easy. Two tips printed right on the board are worth remembering: observe polarity, and after inserting a new battery, plug in the charger to activate it.
Upgrade? Not really. 3,500mAh is about the ceiling for a genuine 18650. A quality cell from Samsung, LG, Molicel or EVE in the same range is a perfect replacement. And if you see an 18650 advertised at 6,000 or 9,900mAh, run. It's fake.
The chassis and lid: the best part
The machined aluminium frame and the four magnets holding the glass lid are the most premium-feeling parts of the whole device. No complaints. Except one: there's a lot of empty space in there. The same internals could fit in a noticeably smaller box.
The display and encoder: prototype energy
This is where the M7 shows its seams. The tiny blue screen sits in a 3D-printed holder; you can see the print texture. The volume knob connects to an off-the-shelf rotary encoder board through a rainbow jumper cable, the kind you'd find in a maker kit. It all works perfectly, and none of it touches the sound. But next to that gorgeous chassis, it looks like a prototype that went into production a little early.
A machined or moulded display holder, a bigger screen to fill that glass top, and an encoder mounted directly on the main board would make the inside look as good as the outside.
What you can't see
The ES9039Q2M DAC, the ES9603Q chips, the Bluetooth chip and the power circuitry all live on the underside of the board, out of view.
The verdict on the internals
The parts you hear are premium: MUSES01 op-amps, real tubes, a modern ESS DAC, a solid chassis. The parts you see are maker-grade. That tells you exactly where Muse spent the money, and honestly? I'd rather it be that way around than the opposite.
Two Personalities, Both Worth Meeting
Here's the thing about a device with two amplifier modes: you're not reviewing one sound. You're reviewing two, and deciding which one you'd actually live with.
So I split my listening. Two albums for transistor mode, where precision and control matter most. Two albums for tube mode, where texture and atmosphere do. All listening on [HEADPHONES], over USB, volume matched between modes.
Transistor mode: Daft Punk, Random Access Memories
If any album exposes a sloppy amp, it's this one. It was recorded like a 1970s studio record with a 2013 budget, and every instrument has its own carefully carved space.
Transistor Mode: Daft Punk - Random Access Memories
In TM, the M7 sounds clean, linear and confident. It doesn't lean warm or bright; it just gets out of the way, much like a good modern delta-sigma DAC/amp should. On "Get Lucky", the bass line is tight and well defined, each note starting and stopping exactly where it should. On "Giorgio by Moroder", as the track keeps stacking drums, strings and synths toward its finale, the layers stay separated. Nothing smears, nothing crowds the centre.
Imaging is precise. Instruments sit in clear, stable spots, and small details like room reverb and cymbal decay come through without being pushed in your face.
Transistor Mode: Swans, To Be Kind
If Daft Punk tests finesse, Swans tests nerve. This album is long, heavy and built on repetition that keeps climbing until it becomes overwhelming.
This is where the M7's power shows. On "Screen Shot", the bass groove stays locked and controlled while the track builds. On the louder, denser passages of "A Little God in My Hands", the M7 doesn't get congested or harsh. It keeps its composure when the music deliberately loses its own. Dynamics hit with real weight, and there's never a sense of the amp running out of breath.
In TM, the M7 is honest, fast and controlled. If you want your headphones to sound like themselves, this is the mode.
Tube mode: Talk Talk, Spirit of Eden
And then you flip to VT, and the M7 changes its personality.
Spirit of Eden is an album about space and silence. It lives in breaths, room tone and the moments between notes. It's also the perfect test for tubes, because tube warmth can either add magic or bury the subtlety.
Here, it adds magic.
Bass becomes rounder and fuller, with more weight in the mid-bass. Mark Hollis's voice gains body and density, sitting a touch more forward and sounding more human. The upper mids and treble get smoother, so the trumpet and harmonica on "The Rainbow" lose any edge without losing their air. The stage widens noticeably left to right, and the choir on "I Believe in You" feels like it's spreading out around you rather than sitting in front of you.
Is it the most accurate presentation? No. Next to TM, tube mode gives up a little detail, a little precision in imaging and some definition at the very bottom of the sub-bass. But accuracy isn't the point. Tube mode trades a slice of resolution for a lot of musicality, and on records like this one, that's a trade I'll take every time.
Tube mode: Nick Cave & The Bad Seeds, Ghosteen
If Spirit of Eden is about silence, Ghosteen is about haze. Floating synth pads, distant piano, and a baritone that sounds like it's being sung from the other side of a dream. On a cold, analytical amp, this album can feel thin and far away. It needs warmth to come alive.
The M7 in tube mode gives it exactly that.
Nick Cave's voice is the star here. In VT, it gains chest and weight, sitting right in front of you instead of hovering somewhere in the mix. On "Bright Horses", the low end of his voice feels full and rounded, and the piano has a soft, woody glow rather than a sharp, glassy attack. On "Ghosteen Speaks", the layered synths and backing vocals melt into one wide, enveloping wash that stretches well beyond the edges of your headphones.
Switch back to TM and everything gets clearer, tidier, a little more separated. Better on paper. But it also feels slightly colder, as if someone turned on the lights in a room meant to be dim. For this album, tube mode isn't a flavour. It's the right way to hear it.
Which mode wins?
Neither, and that's the point. TM is the reference mode: neutral, fast and technical. VT is the evening mode: warm, wide and relaxing. Having both in one box, a button press apart, is the M7's best sonic feature.
Living With the Purple Box
No product is perfect, and the M7 has a few habits you'll need to make peace with.
That screen
The whole top of the M7 is a big, beautiful sheet of glass. And under it sits a screen the size of a postage stamp. I'd honestly love a bigger display here, one that shows the volume and mode at a glance instead of making you lean in. But it is what it is, and the DAC behind it is excellent, so I'll forgive it. Mostly.
More connections, please
The connections it has are great. But for a box this size, I'd love more. A line or preamp output would let you use that tube stage to feed powered speakers or a desktop amp, which would turn the M7 into a tiny tube preamp. A coaxial or optical input would make desktop life easier too. There's clearly room inside.
Everything at the back
All ports and both headphone outputs share one edge, opposite the volume knob. On a desk, it can look tidy. On the go, with a phone attached, your cables all point the same awkward direction.
Buttons that are easy to bump
The side buttons press easily, sometimes too easily. And because play/pause is a long-press of the Menu button, a short press by accident drops you into the menu instead.
Should You Buy the Purple Box?
I went in skeptical. A "Player" that isn't a player. A "portable" that weighs like a paperweight. Four tubes in something with a battery. It all sounded like a gimmick waiting to happen.
It isn't.
The M7 is one of the most honest pieces of portable hi-fi I've used, ironically in spite of its name. It's beautifully built. It sounds excellent in both modes. And it treats you like an adult who's allowed to open the thing you paid for, swap the battery, and roll the op-amps.
It's not perfect. The screen is tiny, the internals look a bit DIY in places, the tubes are soldered in, and "Player" needs to go. It's too big for a pocket and a little light on connections for a desk.
But as a movable, around-the-house headphone amp with a real tube mode, a real transistor mode and a battery that won't turn it into e-waste in five years? At $399, I can't think of anything quite like it.
Buy it if: you want tube warmth and solid-state precision in one box, you like tinkering, and you'll use it at home more than on the train.
Skip it if: you need something truly pocketable, you want a real music player with storage and a screen, or you just need a simple dongle for your phone.
And if you've been waiting for hi-fi to join the Right to Repair conversation, this is a pretty good place to start. In purple, obviously. To Learn more and buy it: https://hifigo.com/products/muse-hifi-m7-player?srsltid=AYCX9vIOo9eF7t5RdebnEzJxtlJphYihyGLrLNxtPszpSaEuxoeNVSOj
Pros
Stunning, solid build, and a colour that breaks every hi-fi cliché
Tool-free magnetic lid, replaceable 18650 battery, socketed op-amps
Two genuinely different sound modes, both excellent
Plenty of power for demanding headphones
aptX Lossless Bluetooth and a 12V desktop mode
Cons
"Player" is misleading marketing
Too big and heavy to be truly portable
Tiny screen under a huge glass lid
Tubes are soldered, so no tube rolling
Few connections for its size; all ports on one edge
Some maker-grade internals (3D-printed holder, hobby encoder)
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