The LoTOO Mjölnir - "High-End All-In-One Portable Audio System"

General Information

What a joy the Mjölnir is! As an update after two weeks of use, I can say that every song, and every headphone, sound better through the Mjölnir. It is subtle, but I think it is true.

  • Absolutely top-notch sound, across all headphones (8) and all recordings tried (maybe 100?) through hours of listening (over the 7 days I have had the system!) – more often than not, hearing new things in familiar recordings
  • Simply beautiful and thoughtful design – robust & easy to use (titanium! tank-like!)
  • Nearly every output jack known
  • Significant power (2.5W/channel in balanced operation).
  • In some cases, sound of Hugo2 with 2Go is slightly preferable.
  • Not really “portable” (weight), but easily transportable (with shoulder strap and case)
  • Tantalizing hint of new features to come via firmware update (e.g., streaming via Roon, wireless audio via LTTP (LoTOO proprietary), Apple AIrplay), but WiFi software update gives error message (manual update works!)
  • Rarely, the user interface “freezes,” yet music keeps playing - requires off/on to regain control.

Built like the chassis of a tank, yet sparkling with refined beauty, the LoToo Mjölnir is both smaller and heavier than I expected during the year-long buildup to my getting one. It plays everything I have given it with impeccable beauty, regardless of which headphone I use.


As a former boss would say, “Enough of the superlatives. What does it sound worse than?”

Let's look at the systems that I have at hand. Does the Mjölnir sound worse than...
  • The LoTOO PAW Gold (original version of 2014)? In listening to just one song, using my Focal Stellia headphones for Jascha Heifetz “Beethoven Violin Concerto in D,” comparing the Mjölnir to the LoTOO PAW Gold, which is my best-sounding portable, the Mjölnir sounds better… more immersion (sort of like being more evenly surrounded by the music, rather than just a left side and a right side with a hole in the middle…my description exaggerates what is a subtle difference, but it is there.) The Mjölnir is also just a touch brighter. So… NO!
  • The Schitt Gungir Multibit DAC and HiFiMAN EF-6 amp? With my HiFiMAN HE-1000 headphones, I listened to “You’re Gonna Miss Me When I’m Gone,” a test song that I’ve used to compare over 100 headphones, concentrating on several factors (bass drum “twang,” sound stage width, sharpness of snare drum snap, clarity of bass guitar, sizzle of cymbals). Soundstage was just a bit wider on the Mjölnir, the other aspects were comparable, so… NO!
  • The Chord Hugo 2/2Go combination? I use Enrico Inglasies “I Will Survive” from direct memory going into my Hugo 2 via the Chord 2Go and into my Mjölnir and listen with my HiFiMAN HE-1000 headphones. I listen to the first 20 sec or so of that song. Well??? WELL???? They were VERY CLOSE in quality! If I were FORCED to make a distinction, on these 20 sec of one song, I would give the edge to the Hugo 2… its drum snaps were the tiniest bit sharper is this the result of the special 49,152-tap WTA filter of Rob Watts), and its soundstage is just a mite larger. However, I would not notice the difference in anything more realistic than promptly-switched A/B comparisons. So… MAYBE (see below as to why not Yes).
  • The Chord Hugo TT2 with Chord Mscaler set at 16X upsampling? This used Roon to feed the music into the MScaler, listening with the Grado GR2000e. These are very close. If I played either system on its own without immediately comarping to the other system, I could not tell a diference. With very careful listening, I could hear very small differences (e.g. Mjönir a touch brighter, the Chord moving the sound just a bit closer), but these are simply factors of preference, not of quality so… NO!
So in short, the only system that might, on occasion, sound better than the Mjölnir is the Chord Hugo 2 / 2Go, and then only slightly and only on some songs. My wife listened to Amber Rubarth’s “Good Mystery” with the Grado SR125e headphone and preferred it on the Mjölnir over the Hugo 2 /2Go. We also found, in taking two copies of the Grado SR125e (the only headphone that I have two copies of), the difference in sound between these two supposedly identical headphones was significantly greater than the difference in sound between the Mjölnir and the Chord Hugo 2 / 2Go.

When you are sufficiently high up in the audio quality stratosphere, there is not a lot of upward progression that one can find in sound quality. Preference starts to become a matter of how pleasing the sound signature might be (which is subjective), how easy to use the interface is, whether streaming is supported, how portable the unit is, what its battery life is, how powerful it is, etc.



Want to look at the User Manual? Go to

Transport: The Mjölnir is far and away easier to select and change songs than anything using a separate smart phone to control. The physical buttons on the front to pause, skip, and replay respond instantly and precisely; using smart phone control of the 2Go or of Roon has delayed response and sometimes misses the start of the piece. However, for systems controlled by the smart phone, one does not have to lift or position a six-pound brick to see the display or access the buttons -- one must do this for the Mjölnir.

Streaming? Best sound is via USB-C, but wireless streaming via Bluetooth DAC works beautifully!

Wired, via Via USB-C: The Mjölnir accept a USB-C cable in the back, which in turn can be fastened to a source with USB-digital output - a USB-DAC. I have been able to connect Roon and Tidal from my iPhone 13 (Lightening connector -> Apple CCK dongle -> USB-B to USB-C cable), and to my Shanling M0 (stored music only), but not to my Sony ZX-505 nor my iBasso DX-170 nor my USB-C-equipped iPad or iPad Pro (generates message indicating improper USB source). Streaming of Tidal Masters (MQA) makes the Mjölnir display assorted sampling info, from “44K 16X“ on the top, “44K“ on the front, through “PCM 96K 32 bits,” on through “PCM 192K/16X 32 bits” on top, “PCM 192 kHz 32 bits” pm the front. regardless of the position of the MQA Passthrough switch in “Settings.” Roon on the iPhone will also send its digital output to the Mjölnir via the CCK dongle. All sound great!

Wireless, via Bluetooth DAC: Thanks to Leo at MusicTeck, from whom I purchased my Mjölnir, I just was introduced to a Marvelous New Capability:

If you sweep the *middle* of the first screen to the left, you get the screen shown in the photo. Note that this is not the same as pressing the right-pointing arrow that sits to the right of the “Settings” entry on that first screen - this sweep is from the middle.

On that new screen are several delightfully promising entries, as well as an operational entry to allow *wirelessly* sending Roon and Tidal from an iPhone into the Mjölnir, and playing them at what is stated as a 96 kHz, 32 bit sampling rate. It works wonderfully and sounds beautiful.


Note that the following options are shown, with some greyed out, presumably for activation in a future firmware update:
  • Roon Ready (gray)
  • LTTP - Lotoo Tele-Transport Protocol for wireless audio (gray)
  • DLNA - Digital Living Network Alliance (gray)
  • Apple Airplay (gray)
  • Bluetooth DAC (not gray and working - listening to Tidal from my iPhone over it right now!)
  • Digital In (not gray, presume working!)
What a discovery, not in the User Manual. Thank you, Leo of MusicTeck!

Accepts Nearly Every Input Plug: The fact that the Mjölnir has nearly every possible headphone jack output is such a convenience – one need not carry a quiver of adapters, as it can accept all headphone types except for the balanced two-connector type of the Sony PHA-3 and Pono player.

Power: Enough about headphone jacks... what about power? I was asked whether I thought that the Mjölnir could drive the HiFiMAN Susvara. I don't have the Susvara. Susvara stated sensitivity is 83 dB/mw). My least sensitive headphone is the HiFiMAN HE-500, at 87 dB/mW. Let us try to calculate a power level for the Susvara:

Comparing to the easy-to-drive Grado PS1000 at 98 dB/mW, I find that with the Mjolnir output power set to Medium (on a four part scale of Low, Medium, High, Super High), that each click of the volume control is roughly 1 dB. If I switch from Medium to High, it automatically boosts by about 35 dB. To make the HE-500 sound as loud as the PS1000, I need to advance the volume control from 89 (for the PS-1000) to 100 (for the HE-500). That is an increment of 11 on the volume control, and the HE-500 is about 11 dB less sensitive than the PS-1000.

The Susvara sensitivity is stated to be 4 dB less than the HE-500. That means I would have to increment the volume control by 4 more to reach the same volume on the Susvara as on the HE-500. Since I am at the top of the Medium scale for the HE-100 and have to add four more, I must go to the High scale, which adds 35. Hence, I estimate that I would have to back off the volume by 35-4 = 31, to 69. That would give headroom of 35 more on High before I reach 100. I still have the Super High, which might add another 35 dB.

This suggests to me that I have LOTS of power for the Susvara, which is only 4 dB less sensitive than my HE-500 (and I have PLENTY of volume for that on the High scale, and can still go to the Super High scale).

Time To Charge. Well. I tried my Super Deluxe Extra Special Anker iQ USB-C 45W charger. The Mjölnir shows both the current and the power level being transferred during charge (NEAT!). It showed… 0 watts (BUMMER!). Not one to believe displays, I waited for about an hour and checked the charge level… still 11%! So… quick research in manual and on internet tells me I need USB-C PD charger (PD is a fast-charge protocol for Apple devices, entirely different than the iQ protocol of my Android-based Anker charger). So I hook up my Apple charger, and I buy a 60+ W 20V PD USB-C charger (that is what the manual specifies.). Charging to 100% succeeds in less than the 4 hours that the manual promises, even though my Apple charger was less than the 60W recommended. I also order a 65W USBC PD charger (you may want to too as you prepare for your Mjölnir).

Other Features: The Mjölnir has a search capability, though it is not mentioned in the user manual. One can enter a word or phrase next to the magnifying glass and entry field and search for song title, artist, or file. As with other LoTOO products, there is no search or categorization by genre.

One button, labeled TSC, is used to wake either display when they extinguish after a time to save battery power (turn-off time may be set). I use it a LOT!

The leather carrying case is beautiful and durable. The strap that allows carrying the Mjölnir over the shoulder fastens to the Mjölnir, not to the case, so the case may be removed when protection is not needed. The case is a bit of an inconvenience… it blocks all the connectors on the back (including power, used for charging), and its flap that covers the front can put stress on the mini connector, which (based on LoToo PAW Gold experience) might eventually make that connection intermittent (see photo). However, each jack is reinforced with a brass ring.


Areas Likely to Improve: The on-line software update does not work. This is particularly important, because there are clues and bird signs that maybe the Mjölnir will eventually do more. The picture of the screen above dangles some tempting fruits of future capabilities. For example, that menu, as well as early specs in Chinese reported here, indicate support for Roon and Airplay, though those statements have not appeared in the current ads or manuals. Similarly, the current specs mention wireless audio via LTTP (LoTOO Tele-Transport Protocol), but that option is grayed out for now.. Menus in the Mjölnir mention MQA! WiFi works, but an attempt to check for software updates returns “error-37.” Repeated questions to have not been answered. MusicTeck, from whom I purchased the Mjölnir, sent me a link to the sofware update, which I successfully installed. They report that the Mjölnir has been sent to Roon to become Roon certified. Inquiries to Roon (When?!) elicit the statement that they neither confirm nor deny which systems are under evaluation (makes sense).


After some reflection upon my sound comparisons, rather than being disappointed (“$7,000.00 and no eargasm?!”), I concluded that either all of these systems are so close to Summit-Fi perfection that there is no room for improvement but only slight differences, or my ability to both detect and judge differences is less than the differences in these systems. In other words, “constant eargasm!”

Usability is top notch, and the system is absolutely, breathtakingly beautiful in appearance and in sound. Day and night, below, the system is fantastic!





Member of the Trade: Audio Essence
Excellent review. Thanks a lot!

Remark: Mjölnir does indeed work with Roon already. I tested it yesterday by simply connecting a laptop via USB-C cable.

This way you can use streaming services already.