Lotoo Mjolnir: Thunderstruck – A DAP Review

DISCLAIMER: I’d like to thank Lotoo for giving me the opportunity to review the Mjolnir. I am not personally affiliated with the company in any way, nor do I receive any rewards – monetary or otherwise – for a positive evaluation. The review is as follows.

This review was written primarily with firmware 1.4.0.6, then with beta firmware specifically for LTTP connectivity.

Lotoo is a brand world-renowned for their portable audio sources. Bursting onto the scene with the PAW 5000 and PAW Gold, their most recent flagship, the PAW Gold Touch, rapidly became the reviewer’s go-to DAP; hailed for its remarkable technique and neutral tonality. Subsequent releases like the PAW 6000 and the S dongles saw them make their mark on the bang-for-buck category too. Late last year, however, Lotoo announced their play for yet another quadrant: The transportable market. The Lotoo Mjolnir is a 2.7kg behemoth of an audio player, it is the brand’s most ambitious project yet, and it takes their technical neutrality to a whole new level.

Lotoo Mjolnir

• DAC chip: AKM AK4499EQ
• Audio I/O: 3.5mm/6.35mm (SE), 4-pin XLR/4.4mm (BAL), RCA (SE LO), XLR (BAL LO)
• Output power: 1.2W @ 32Ω (SE), 2.5W @ 32Ω (BAL), +18dBu (SE LO), +24dBu (BAL LO)
• Sample rate support: Up to PCM 768kHz and DSD512
• Key feature(s) (if any): LTOS, LTTP
• Price: $6999
• Website: www.lotoo.cn

Page 1: Introduction, Unboxing and Accessories, Build and Design, Physical Controls, Battery Life
Page 2: Connectivity and Storage, Wireless Audio, GUI and Presentation, Navigation
Page 3: Sound Impressions and Power
Page 4: Select Comparisons, Verdict

Unboxing and Accessories

The Mjolnir arrives in a massive, white box with nothing but its name and brand sparsely printed on the top and side. It’s a slight downgrade from the textured finishes and gold accents on their recent releases, but it’s no huge issue.

Beneath the lid, you’ll find the Mjolnir and its accessories (in their individual boxes) sandwiched between enormous layers of foam, ranging from 6-12 cm thick. On one hand, it’d be nice if Lotoo could’ve cut that back to save on shipping. On the other, with a product as hefty and expensive as the Mjolnir, ‘better safe than sorry.

Beneath the middle layer of foam, you’ll find two accessory boxes. The first has a USB-C to USB-C cable, which they’ve cleverly braided with a silver-and-black color scheme, unifying their past and present aesthetics.

What I am disappointed to find, however, is that the Mjolnir does not come with its own power adapter, nor have they provided an additional USB-C cable for charging purposes. I think these are glaring oversights, especially when they’re necessary to turn the device on. And, it also opens up room for users to use ill-fitting or unideal adapters, which may end up harming the battery or, at the very least, hurt its longevity. To be fair, Lotoo have specified the ideal specs for a power adapter in the manual: Over 60W and 20V in output. But, I think these necessities that, again, are required just for the product to function must be included by default, and for Lotoo to skimp on something this basic is quite a letdown. I hope they rectify this in the future.

The second and final accessory box has:

• 1x user manual
• 1x warranty card
• 1x microfibre cleaning cloth
• 2x sets of tempered glass screen protectors, but only for the top touchscreen.

The front, secondary screen doesn’t get a guard, which I think is an oversight. Even if it isn’t expected to receive any physical contact, I’d still expect Lotoo to give it an optional protector, especially for a flagship product.

I have to give special credit to the user manual, which comes in multiple languages and covers a wealth of detail. For me, the only notable exclusion is how to use PMEQ. Even if the full, customizable version of the app isn’t on the Mjolnir yet, they might as well include it should they ever choose to add it in an update. Plus, If you look at forum threads discussing Lotoo’s recent DAPs, the most common question you’ll find is, “How do I use PMEQ?” So, some basic starting points or, better yet, a link or QR code to an instructional video would be something I’d add in future printings of the manual.

Carrying Case

Inside the larger accessory box, you’ll find the Mjolnir’s included leather case. It comes in a saddle tan color and in two separate parts: The main leather bag and the leather-and-fabric strap. The strap is designed to attach directly to the Mjolnir by looping in and around its two “handles,” and it closes those loops via Velcro. The strap’s length is also adjustable, simply by feeding the strap through the metal hoop.

It also comes with a lightly-padded, leather, shoulder cushion, which attaches onto the strap via buttoned clasps; a clever system that makes it easy to add or remove at any time.

Once the strap is attached to the Mjolnir’s chassis, you can then slide it into the leather trunk, in which it fits very snugly. Once fully inserted, the case has leather fasteners, which screw into a screw hole on the left and right sides of the Mjolnir’s shell. Screwing both in will lock the unit in place.

First off, I must say that everything here is thankfully of exceptional quality. The leather is thick, well-oiled and befitting of a product of this caliber. Accessories as lazy afterthoughts are a tragic epidemic in the industry, so I’m glad to see Lotoo haven’t caught the bug. The stitching here isn’t only color-matched, but even all around as well.

The side grilles for ventilation are precision cut. And, finishing touches – the Lotoo and Mjolnir embossings, as well as the magnetic button clasp, which they’ve made to look like the Mjolnir’s golden wheel – are all extremely well done. The strap is similarly robust, light on the shoulder, and just well thought-out overall.

For me, there are two things missing in this case, and they both relate to accessibility. One is a way to access the top screen. There isn’t a top flap that opens to expose it. Second is any way to access the rear I/O. I’m shocked Lotoo haven’t included as little as a hole for the charge port. So, if Lotoo offer an alternate case in the future (or, better yet, a free upgrade for existing Mjolnir owners), I’d like to see those two things rectified.

A smaller concern for me is the side fasteners. Again, you have to screw them into the Mjolnir’s chassis, but there’s no way to see what you’re doing as you do so. So, you have to feel for the screwhole, and there’s a chance you might scratch your Mjolnir with the metal screw if you miss the hole and attempt to turn it. You have to aim the screw very slowly, have full faith that it’s in, then screw it in. My recommendation for a future case would be to have a guide of sorts, so the screw can’t touch the Mjolnir unless it’s aimed perfectly at the screwhole. Or, it would be to use screws made of silicone (or some sort of softer material), so even if you miss the screwhole, you won’t scratch your $7000 flagship product.

Build and Design

Simply put, the Mjolnir’s build is immaculate. While I regret seeing them part from their primarily black aesthetic, I can also admit that this silver beast is one of the most luxurious-looking and feeling pieces of audio gear I’ve ever encountered. Its aluminum-alloy shell sports an exquisitely refined finish – think Macbook, but smoother – and packs in a ton of sharp, chiseled lines, as if to show off how much better their CNC machine is than everyone else’s. And, underneath are four, domed, rubber feet for protection and stability.

Throughout, there isn’t a single part of this chassis that implies cheap or afterthought. Every one socket, button, surface and screw-hole looks meticulously thought through, splendidly machined and, most importantly, befitting of a $7000 price tag. In my opinion, what makes a flagship piece, beyond the joy of using it, is the pride of owning it. From looks and feel alone, Lotoo have aced that completely, and I must laud them highly for the effort.

Peering a bit deeper, you’ll find tons of intricate details strewn throughout the device’s silhouette; from the machined nametag on the top-right, to the two-layered heatsinks (where they’ve hidden their logo). Then, design cues like the slight raise on the touchscreen, the flared handles and the angular input selector all strike the perfect balance between workhorse and showpiece. Topping it all off is Lotoo’s signature volume wheel, more radiant and gold then ever before, surrounded – as usual – by a ring of light (which you can turn off in the device’s settings, if you wished to). The added real-estate has allowed them to etch deeper, more detailed lines than the ones on any of their DAPs, and I think it’s a brilliant crown jewel to top off their statement piece.

And, as you can probably tell from the pictures, every single screw, rivet and socket is perfectly inlaid; utterly without fault. The same goes for every dial and switch across its faceplate. From top to bottom, back to front, the Mjolnir is a flawlessly-crafted device. Whether it’s the finish, the construction or the aesthetic language, I don’t think Lotoo could’ve done much better. Again, the continuity obsessive in me would’ve preferred if it came in black, but it’s a minor niggle in what is otherwise a market-leading effort.

As a high-end, desktop-grade DAC/amp combo, I actually find the Mjolnir impressively compact. Compared to its natural competitor, the Sony DMP-Z1, the Lotoo flagship is about 30% smaller, and it isn’t that much bigger than the Mac Mini it’s sat next to on my desk. Though, it does pack quite a lot in weight. The Mjolnir comes in at 2.7kg, which, again, isn’t outrageous for a desktop device, but could pose a challenge if you wanted to lug it around. I think it’s too heavy to use like a Hugo 2, where you can slip it in a messenger bag and carry it to cafes. The Mjolnir’s more for, say, a multi-night, hotel room stay, I reckon.

Battery Life

The Mjolnir has a 9000mAh Lithium ion battery, and it held up surprisingly well in my tests. With the amp at Middle gain and 50% volume and the DAC decoding 80% lossy AAC and 20% FLAC and WAV, I was able to get around 10 hours of playtime before the battery died. When I did the same with Super High gain, I was impressed to find that I got nearly the same result. Obviously, the battery will wear quicker if you turn on features like Bluetooth. The same goes for playing back formats like DSD. But, all in all, you’ll get about as much play out of the Mjolnir as a modern-day DAP.

Charging the device with a 65W Baseus charger, the Mjolnir was pulling 22.5W and 19.5V. The battery returned to full in less than 5 hours, which is a little more than the “around 4 hours” they cited in the manual. But, it’s close enough, and I think that’s beyond reasonable for a device of this size. Remember, again, you’ll have to find your own USB-C charger, because Lotoo didn’t provide one with the Mjolnir, but anything beyond 60W and 20V should get you these numbers confidently. Also, it’s worth noting the Mjolnir only charges as much as it has to, so I don’t expect the battery to wear out or bloat from overcharging.

Physical Controls

The Mjolnir is unique in that it doesn’t have buttons. Instead, its physical controls consist mainly of switches, and beneath them are dots and rings. Dots indicate a position where the switch can lock or stay in place, while rings indicate a position the switch can be pushed towards, before returning to its locked, dotted position.

The first two on the top-right-hand corner of the device are Hold/TSC and Power.

When the former switch is in the Hold position, it’ll lock the volume wheel at a software level. Attempts to turn the dial will only display the Hold message (as seen below) on the front screen. Pushing the switch back to the middle position will restore the volume dial’s functionality. Whereas, pushing it towards TSC will wake both screens up when the Mjolnir is asleep.

The Power switch is self-explanatory. When the device is off, pushing it to the right will turn it on. You can repeat that operation to power the Mjolnir down, but you’ll have to hold the switch in place until the progress bar on the screen fills up completely. If you let go before it does, the shutdown will be aborted. As an added feature, when the device is off, you can nudge the switch to the right for just a moment to briefly turn on the top screen and show the Mjolnir’s battery life and charge status. Doing so when the Mjolnir is on will either put it to sleep or wake it up, depending on which state it’s currently in.

The remaining three switches lie along the bottom of the device. All three sit in a central neutral position, and they each activate a function when pushed either left or right. These are their left and right functions:

1. F1 and F2
2. Pause and Play
3. Previous and Next

The F1 and F2 switch is a user-customizable one that you can set in the device’s settings, the options for which include:

1. Mute
2. Mute -20dB (which, should have more accurately been called Pad -20dB)
3. ATE
4. PMEQ
5. Loop Mode (as seen in the picture above)
6. Sleep Timer

For the mute functions, toggling between F1 and F2 just switches them on or off. In the last four modes, doing so will cycle between the numerous ATE filters, or PMEQ presets, etc.

Then, between all those switches, we have the Mjolnir’s output selector. You can toggle this wheel between the five listed options:

1. 4.4m/3.5mm (Note: The 4.4mm output will take precedence, if both sockets are occupied)
2. 6.35mm
3. 4-pin XLR
4. Line Out
5. Digital Out

While its function is self-explanatory, I must highlight the selector’s stellar build. Whatever switch Lotoo’s selected here feels immensely satisfying to turn and hear click. It’s one of those tactile experiences, though small and oft underestimated, is a constant reminder that you’re handling a luxury, premium product. The same goes for the switches, which move with buttery smoothness. I adore that Lotoo have eschewed the buttons and levers seen on dozens of sources in favor of something that feels unique. As I said, there’s merit to the pride of having something one-of-one, and touches like these are how you achieve that.

Nowhere is that sentiment better exemplified than on the Mjolnir’s golden volume wheel. Like the switches, it turns with satisfying smoothness. But, there are also bumps to indicate every step you’re moving in volume. I personally prefer this over your free-spinning potentiometers, because it gives me a level I can remember and repeat for each of my transducers. And, once again, it’s another display of the Mjolnir’s excellent craftsmanship and lavish feel.

Screen

The Mjolnir sports two screens: An 800×480 touchscreen on top, and a 480×360, 2.2-inch, LCD screen on the front. Both screens feature the same technologies as their PAW DAPs, which are:

1. Anti-Fingerprint Coating
2. Diamond-Like Carbon Coating
3. Gorilla Glass
4. IPS Display

This makes both screens more resistant to fingerprints and smudges, and it seems like it does so by making the panels less reflective. So, it doesn’t bounce light back onto those blemishes. Obviously, they’ll still be at least a little bit visible, especially if you handle the screen with dirty digits. But, it’ll hide those marks better than most, and cut down the need to wipe it with a cloth.

The Gorilla Glass and Carbon coats also make the screens very durable. And, the IPS display not only gives the screen superb contrast (blacks on it are particularly dark), but it guarantees excellent viewing angles too. Where the Mjolnir is on my desk, I’m constantly looking at the top screen at a 45-degree angle, and the colors look about as good as if I were looking at it straight on. And, thankfully, those technologies haven’t gotten in the way of the touchscreen’s sensitivity, which is snappy and accurate in capturing my inputs at all times.

The two screens also feature the typical power-saving feature, where they’ll turn off if the device has been left idle for a certain amount of time. You can set how long it takes before the screens do so in Player Setting, or you can assign that function to the F1/F2 switch.

If I were to suggest anything to Lotoo, it’d be to take more advantage of the secondary screen. It’d be cool if the screen showed part of the now-playing track’s cover art behind all the text. Or, for a more practical idea, whenever a USB connection is detected and we’re asked to choose between Storage or USB DAC, have the options appear on the front screen instead. Then, we could use the F1/F2 switch to make our choice. That would allow the Mjolnir to enter USB DAC mode without having to interface the top screen at all; ideal for those who want to tuck the Mjolnir away neatly under a desk shelf or something.

Having the option to toggle between Bluetooth or LTTP input just with the F1/F2 switch and front screen would be extremely convenient too. So, I think there’s a ton of untapped potential for this secondary LCD, which Lotoo could easily introduce via future firmware updates.