Lotoo Mjolnir

Thank you, as always, to Andrew and Musicteck for the chance to review this product, you can find the Lotoo Mjolnir and other Lotoo products at https://shop.musicteck.com/collections/lotoo

I had absolutely no plans on buying MORE gear, but attending CanJam NYC 2024 lead me to demo the Lotoo Mjolnir at Musicteck's table and was absolutely blown away in moments by it's sound. I'll be doing a comparison to other top of the line DAPs/Amps such as the Astell and Kern SP3000/Mass Kobo 475, and the iBasso DX320 Max/PB5 using the Noble Audio Viking Ragnar paired with an EA Centurion, Nostalgia Audio Tesseract paired with Magnus 8w and Unique Melody Red Halo.

Packaging:

The Lotoo Mjolnir comes in a beautiful, minimalistic large white packaging, very well secured by thick foam and accessory packages containing a USB OTG cable, manual and screen protectors (only for the top screen, smaller front screen is left without one). The only other contents are the leather carrying case/arm strap for the Mjolnir. The case is a gorgeous brown leather, with a top flap to be able to utilize the screen without removing the case and has a securing screw in mechanism on the sides. The only real flaw with this case is, the back is completely covered, meaning you can't use the Mjolnir with any back input/output while in the case, you'd be limited to bluetooth connection and front outputs (3.5mm, 4.4mm and 4pin XLR). The one nitpick here is, for a source of this price, it does NOT come with any charging cables or plugs so worth noting you'll need a fairly hefty charger capable of putting out 30w/20v (Lotoo advertises 60w charging but utilizing a charger/cable that can output far more than this, I've always capped at 30, not sure if user error or they limited it in a firmware after release or what, not a big deal but just noting it).

Build Quality/Software:

The Mjolnir is a stout, fairly heavy and well constructed transportable source. Both screens are crystal clear, the top touch screen is very responsive and has no lag or input issues, double tap to wake screen can be a little finnicky but once you get used to it, it's a non-issue. Mjolnir, even if used while charging remains only warm to the touch as worst, so it's ability to dissipate heat is very good, with the side grates/vents looking to be the only real source of cooling other than radiant heat through the body. As mentioned in the Pros/Cons, the Mjolnir is a tad heavy but it's nothing that is intrusive or bothersome even when carrying on my shoulder via the included case I didn't feel any fatigue from it's size.

Onto the software side of things, boot time is fast but, this is either a love or hate, when plugging or turning on your source (for me, AK SP3000 via usbc), the Mjolnir will go on as well, offering the option to select your input/output type. This is the note in my "Con" section, you'll need to FIRST turn on your source, which will turn on the Mjolnir, but need to wait for the source to completely boot before selecting "USB DAC" on the Mjolnir, otherwise it won't work. If you do happen to select the option too early, you must unplug the usb c from the back of the mjolnir and replug it, which the option will then pop up again and can be selected. A very minor annoyance, which once you get used to operating it is fine. Another order of operations task is when shutting down, first you must shut down your source, and make sure it is COMPLETELY off, then shut down the Mjolnir by holding the off switch for a few seconds (the screen shows "progress"). If you shut the Mjolnir off first, then the source, the "auto on" when a source connects turns the Mjolnir back on. All in all, the software, navigation and ease of use are all great, it's just minor nitpicks.

In terms of options/features, the Mjolnir is fairly feature rich and easy to navigate/select exactly what works for you. For the purposes of this review, I'm only going to cover "sound altering" options, as the others are user preference/pretty standard to any piece of technology currently on the market (auto off, screen off, etc etc). Being an AKM chip, you have your standard AKM filters, such as slow roll off, fast roll off, etc, these work well and offer exactly what you expect if you're familiar with them, my favorite being Slow-Roll-Off as it is the most true to sound (if you want to read further on these and how they work, see this link https://addictedtoaudio.com.au/blogs/how-to/how-to-pick-the-best-filter-setting-for-your-dac).

There is also a built in PEQ which I have not fiddled with much, as I never EQ anything, but from a few other friends who have purchased a Mjolnir as well, these work very well and offer a breadth of options/tonalities for those who enjoy EQing. For me, the most important and substantial option is XRC. This is Lotoo's built in upsampling feature which upscales PCM playback to 32 bits (from either 16 or 24). I noticed a pretty substantial gain in soundstage depth, width and height by switching this option on and have since left it on always.

Another big selling points of the Mjolnir is it's power output. This little beast can go all the way up to 2.5w of power per channel, offering low to super high gain, anything I threw at it was able to be driven and while I don't own any full sized cans, other users have noted that it is able to drive most full sized headphones with ease or at least to their "minimum" required (Susvara, it needs a bit more than Mjolnir can put out). The Mjolnir drives all of my IEMs well and completely silent as long as I don't crank up the gain too high, for Ragnar/Centurion I'm able to go to medium gain, high and super high introduce very light background noise. Tesseract anything above medium is a bit much and Red Halo was able to go to high without any noise/little volume control. So for IEM users, you'll have no issues with any IEM out there.

For functionality from various sources/connection types, I tested bluetooth, USB-C from a DAP, Phone and PC. I wasn't able to test CoAX as I don't have a source capable of outputting via CoAX but other users I known have tested and said it functions/sounds very good, possibly slightly more "analog" than USB-C which was slightly higher resolution to them. I noticed bluetooth, even when using the highest quality available was ever so slightly lower quality then a hardwired connection, which was expected, but it was absolutely top tier none the less and in no way would be a deterrant to me owning it if I could only connect via bluetooth. When testing various sources via USB-C whether it was a DAP or my PC I didn't notice any difference in quality via USB-DAC setting on the Mjolnir and it worked plug-n-play with my windows PC, no need for any drivers. USB-C is also where things get a little finnicky, again, it is picky with it's OTG cable being used. The included usb-c cable worked perfectly with my PC, but when trying it with my SP3000 and Android phone, it did not detect the source input. This was rememdied with a quick swap to my DD-Hifi OTG cable, to note, other OTG cables I tried had the same issue, from the expensive L&P one down to generic ones pulled from my phone.


SNR/Background:

One of the most impressive aspects of the Mjolnir, it is the first source I've heard that has matched the Astell and Kern SP3000's black background. There is absolute silence behind your music. I found on several songs which have halts and silence in them that I was checking if my playback stopped because there was just complete, blackhole silence. Notes pop in and out of this darkness which feeds into making the already amazing dynamic range of the Mjolnir to seem even more impressive. Micro details are extremely easy to pick out and, in the below soundstage/imaging section, this plays a massive part in how grand the Mjolnir is able to project sound. These traits are especially impressive when paired with the Viking Ragnar, which already has, in my opinion, the best detail and overall technical performance on the market currently. So if you're a Ragnar lover like myself, this pairing is end game, hands down.
SP3K: As stated, this is the one source that I've found other than the Mjolnir that is able to have notes popping out of complete silence/darkness. The Mjolnir does come across as more impressive in this area though because the SP3K has slightly less dynamic range to it, so quieter notes aren't as quiet and the top end doesn't reach as loud. The SP3K is also a bit smoother and less overall punch, which I'll touch on in the Bass section below.

SP3K w/ Mass Kobo 475 Amp: Loses the level of blackness that the SP3K and Mjolnir are able to achieve. While still on the upper echelon of amps, the 475 does have some issues with more sensitive iems and channel imbalance/background noise when adjusting the volume wheel. The Mjolnir doesn't have any of these issues, despite having far more power on tap than the 475.

DX320 Max: The Max is one of the most impressive daps at the moment, boasting the most powerful amp out of the current ToTLs and while it's background is quite dark even with more sensitive iems, it does not reach the level of either Mjolnir or SP3K but does beat the 475. Ultra quiet notes within songs dont have the same level of darkness surrounding them and have a bit of intrusive noise which makes micro details a bit harder to discern.

320 Max w/ PB5 Amp: A very impressive amp when it comes to portable tube amps on the market, but as typical of tubes, the background is not as black as even solo 320max, thus it does not come close to the capabilities of the Mjolnir in micro detail discernment or overall presentation.

Soundstage/Imaging/Transients/Layering:

While the blackness of the background is one of the most impressive aspects, the soundstage and imaging are by far the biggest wow factor of the Mjolnir. The soundstage spreads wide, deep and tall while the most impressive imaging I've ever heard from a source is able to fill in every corner of the massive, holographic stage. Throughout my various test songs I found myself continuously floored by the level separation and accuracy of the instruments. The Mjolnir also boasts lightning fast )) transient speeds that pair perfectly with the Viking Ragnar. Any IEM set that already has an impressive ability to expand staging and fast transients will pair well with the Mjolnir, as I found with my Indigo, Red Halo and Tesseract. The ability of the Mjolnir to layer sounds is also far beyond that of any source I've heard, from bass to treble, all instruments are layered and scattered according to the exact positioning of the band. This is especially noticeable with vocals when there is more than one singer on the stage, you'll be able to pinpoint their relation to eachother and the band. If you're a listener that focuses on these criteria, the Mjolnir is a must buy.
SP3K: While retaining a holographic soundstage, the overall sphere is smaller than the Mjolnir. The biggest difference being in overall width, depth and height are closer, but still far in favor of the Mjolnir. The SP3K has an impressive imaging capability, and while it's still up there as one of my top picks in the category, the Mjolnir is leagues ahead. There's such breadth to the sound that it is able to spread instruments across that no other source I've heard is able to compete with, even my beloved SP3K. The SP3K is also a bit slower in transient speed, in order to keep the standard "AK" house sound, of being smoother and more relaxed.

SP3K w/ Mass Kobo 475 Amp: Compared to stock SP3K, the stage expands wider and deeper, with height remaining very similar, possibly in favor of SP3K. The imaging capabilities are similar to stock SP3K but due to the much fuller sound and heavy note weight that is presented by the 475, it does not sound as clean or well imaged as the SP3K as notes have more of a tendancy to overlap, let alone the Mjolnir which is pristine sounding. The Mass Kobo 475's biggest improvement over the stock SP3K amp is it's faster transient attack, which allows it to be a much better pairing for music such as metal, but none the less still slower than that of the Mjolnir.

DX320 Max: Very similar to my above 475 w/ SP3K comments, while the 320max is a very adept source and is one of the top portable sources currently on the market, it's imaging, while very good, does not contend with the like of the Mjolnir or SP3K. In terms of soundstage however, the 320max is a match for the 475 but doesn't have quite the holographic presentation of either the Mjolnir or SP3K, most notably lacking in stage height. The transients of the 320max sit somewhere between that of the SP3K and the 475, being faster than the former and slower than the latter, which helps keep a bit of "musicality" to the 320maxes sound while still being rather clinical/analytical.

320 Max w/ PB5 Amp: Compared to solo 320max, the PB5 brings an airier, wider, deeper and taller soundstage presentation, reaching a near holographic level, with improved imaging. For me, the addition of the PB5 is a direct upgrade to that of the stock 320max. It's worth noting that, while these aspects as improved over the 320max and the staging size is closer to the Mjolnir, it is still magnitudes smaller, with the same commentary applying to it's imaging capabilities. With the PB5 attached, the 320max goes from the middle of the pack to the slowest of the transient speeds of the compare group so far, leading to a smoother, more musical playback than the above.


This section will be briefer than typical in the straight sound profile explanation due to the fact that the Lotoo Mjolnir is a very clean, transparent and neutral source, allowing your connected iem's tuning to really shine through and just elevating the presentation and technicals to the next level. Instead, I'll try to focus on direct comparisons to other sources above and how my IEMs have benefitted. From others in the community I have spoken to, which have owned other Lotoo products as well as the Mjolnir, this seems to be their house sound, and it's now something I'm very hooked on. If I was forced to pick a "tuning direction" of the Mjolnir, it would be a very light W style tuning.

Bass:
The first thing I noticed when using the Mjolnir was how tight and precise the bass was, there's no bloom, bleed or other artifacts spilling outside of its appropriate range. There is a slight noticeable sub bass lift, as stated above, part of that light W tuning, that helps to keep music a engaging while being highly analytical. The sub bass extension also reaches very deep, extracting every little nuanced detail down low. Mid bass is well controlled, and with the Ragnar, which is already "lighter" in this area, the Mjolnir allows heavy amounts of micro detail as there's no bloat/mud present and vocals can shine through with even the most minute/low background nuances able to be discerned across the massive stage. With a more vocal focused and even less bass leaning IEM, such as the Red Halo and Tesseract, the clarity brought by such a clean presentation in the bass allowed me to truly enjoy the very specialized and focused tuning of the Red Halo as all of the details and air that the IEM brings were able be the star while the light sub bass lift helped the tactility of it's bone conduction driver. I noticed similar benefits in my Indigo and brief trials I had with my Trifecta (before selling it), the bass had an excellent tactility to it, which both of these IEMs already excel at, but the way the sub and mid bass transitions were to their surrounding areas were so clean and tidy that no details were lost, even on the Trifecta which is known to be more "muddy" than transparent.

The biggest benefits of the Mjolnir over other sources all lie in the technicallities above, this is not a source that's going to inject bass quantity and turn a bass light iem into a brain thumping monster, but it will elevate those bass head iems to the next level through soundstage expansion, well beyond summit-fi imaging and transparency as well as deft control. Guitar string plucks, drum hits and reverbs are all ever present and able to be easily discerned while listening and it truly creates a next level of engagement with your music.


SP3K: Control and finesse of the SP3K is similar to that of the Mjolnir, but the biggest difference between their bass presentations is the level of dynamism. The Mjolnir has a much higher degree of dynamics and dynamic range, allowing the bass to sound much punchier and have an overall greater PRaT (Pace, Rhythm and Timing). The SP3K goes for a smoother approach to achieve a more musical sound as opposed to the pure accuracy/neutral goal of the Mjolnir. Bass quantity between these two is very similar, staying true to the original recording and not adding or subtracting anything.

SP3K w/ Mass Kobo 475 Amp: I've always found the 475 to lean J to V shaped in it's presentation, having the largest impact on bass quantity and creating a much fuller, boomier bass response. The 475 has the characteristic of being "always-on", regardless of the bass quantity in the recording, the 475 increases it and the sound is anything but smooth. There is less finesse and control over the sound than the Mjolnir, if you're someone who wants bass quantity over all else, then the 475 would be a good pick for you. There is also less detail here due to the fullness and size of the notes, everything being increased in volume and sacrificing some quality for that effect. The Mjolnir provides a MUCH higher resolution and quality bass than the 475 is able to.

DX320 Max: The 320max is similar to the 475 but leans more toward a U/W shaped sound, so while the bass is prevelant and boosted, it is not nearly as far reaching/all encompassing as the 475. iBasso's Dx320 Max has a well controlled and quick paced bass that is similar to the Mjolnirs, but has less overall resolution, depth and clarity as well as having a boosted quantity in comparison.

320 Max w/ PB5 Amp: Being a tube amp, this presentation is the furthest away from that of the Mjolnir. The PB5 keeps roughly the same bass quantity as the 320max stock, but it introduces a bit of mid bass bloom typical of tube amps. This creates a bass response with slightly less clarity, but more cohesive and fuller without sounding "boomy" like the 475. The speed of the bass is much slower than the Mjolnir, with a longer decay which contributes to the aforementioned bloom.

Mids:
While writing my notes for the mid and vocal range of the Mjolnir, my initial thoughts where "effortless, smooth but detailed with outstanding clarity, resolution and ever so slightly forward". Once I drew the former conclusion, I started flipping through my library for my favorite tracks or those where I especially hone in on the vocals and I immediately started noticing new details and minute, deeply buried nuances such as echoes, singer breaths, etc. Tonally, the mids and vocals remain as transparent and uncolored as the rest of the frequency response of the Mjolnir. With vocal focused sets such as the Red Halo and Tesseract, the depth of their coloration and neutrality (in Tesseracts case) becomes fully apparent. Male vocals are able to sound hefty and weighty if your monitor is tuned as such and female vocals will remain sibilant free. Mjolnir will always allow your sets tonality and tuning to come through, just bolstering it's ability to provide detail, clarity and resolution first and foremost. Despite being so transparent and resolute, this is not a sound I'd ever classify as cold, the Mjolnir is somehow able to retain excellent musicallity and engagement despite how highly analytical it is.

SP3K: While retaining an almost equal level of detail to the Mjolnir, the SP3Ks mid range is a bit warmer in tonality, lending itself to be slightly less micro detailed without losing too much clarity in it's sound despite the additional warmth. Even with this sweeter, more intimate vocal presentation, I do prefer the Mjolnir for even vocal focused tracks and IEMs, Red Halo and Tesseract are able to push so much detail through that even the SP3K, my once favorite of all time sources, was beaten handedly.

SP3K w/ Mass Kobo 475 Amp: Almost directly oppposite of the Mjolnir, the mids and vocals here are pulled back a bit, lending again to that J/V shaped signature. They are also less detailed and can sometimes be marred by the over zealous bass. There isn't bass bleed into the mids, but detail and resolution are dulled by the quantity of the bass that pervades the presentation. There is also coloration to the mids as opposed to the transparent Mjolnir, adding more heft and grit to male vocals and female vocals can be a bit brighter due to the lower treble lift.

DX320 Max: Similar to the SP3K, the mids of the DX320 max are lightly colored with a mild elevation, greater than that of the Mjolnir. There is an added weight, similar to that of the 475 but much less heavy handed and without the overwhelming bass that detracts from micro details.

320 Max w/ PB5 Amp: The warmest and most forward of the compared sources, the PB5 has a blend of your typical tube sound with iBasso's house sound (detailed, airy, slightly analytical), which is a truly impressive blend of characteristics. There is rather drastically less detail when directly comparing the Mjolnir and the PB5, but the PB5 is specializing in tone and musicality, so it's happy to sacrifice some technicalities for it. The bloom mentioned from the bass is never an issue with bleeding into the mids, it remains controlled and clear throughout with a nice flow, decay and note size throughout, being slower and larger, respectively, than the 320max stock. This is more of a complimentary sound to that which the Mjolnir is offering, but still worth noting that the Mjolnir is once again the king of detail (Clarity+Resolution), accuracy+layering (imaging) and speed (transients) in the mid range, as it was in the bass!

Treble:
Akin to the bass, the treble presented by the Mjolnir is effortless and very very well extended. There is no harshness, quantity, sibilance or splashiness that is added/amplified. True to the Mjolnirs form so far, there is also zero coloration to the treble, this is the truest, most neutral source I've had the pleasure of listening to. While using the Ragnar, I am able to hear the initial strike of cymbals down to the last reverb as it fades off into the pitch black background. There is an abundance of air (part of my aforementioned light W shape) which is lightly amplified but this only assists in making the sound grander and the stage larger, which is all subsequently filled in, top to bottom, corner to corner by the exceptional imaging brought forth by the Mjolnir. Paired with BA treble iems, such as the Red Halo, the Mjolnir is able to keep the weight that I typically associate with BA treble vs EST treble (which leans wispier/lighter with less edge to it) in tact, which was a great surprise considering how fast the transients are. I personally owe this to the outstanding extension which, despite the quick decay, is able to present the entire note through just as well as EST based treble IEMs like the Ragnar and Tesseract were able to! Truly an amazing feat for such a (trans)portable source.

SP3K: Treble from the SP3K is also well extended but not to the the degree that the Mjolnir is able to push the bounds. There is also a slight quantity boost to the lower treble by the SP3K while air is not extended as much, which the Mjolnir is the direct inverse of. Opposed to the Mjolnir, BA treble can sometimes lean a bit light and sharp on the SP3K (fine for me, but I know others can be sensitive) and EST treble will indefinitely extend more than that of BA treble. While Mjolnir can present any type of driver at their absolute best, the SP3K shows it's limits and design choices in remaining smoother to obtain it's musicality here.

SP3K w/ Mass Kobo 475 Amp: The 475 adds quantity and weight to the treble, following the same philosophy as the bass, there is more energy and lift in the treble region in order to balance out the elevated bass. The elevation is in the transition from lower treble to upper treble so female vocals are not skewed or tonally inaccurate due to the lift. While extension of the treble is less than that of the Mjolnir it does not fall behind the stock SP3K, keeping pace but slightly smoother on BA treble IEMs

DX320 Max: More reserved and works to tame treble a bit. This creates a more linear presentation where, if peaks exist that could be troublesome for sensitive ears are reduced. Similar to the 475, note weight of treble is also increased and has a heavier more thunderous ring with less overall extension than either the 475, SP3K and especially the Mjolnir. Quantity is also slightly increased, but less than the 475.

320 Max w/ PB5 Amp: Taking the above notes of the 320 max, the pb5 pushes the enevelope further in the same direction but does add a bit of decay, which helps overall treble extension and a greater sense of air is present on the PB5 than stock. There is also slightly less note weight in the treble on the PB5 than the 320 max, sounding more natural and true to life. While the Mjolnir remains neutral and your IEMs overall tuning will shine through, the PB5 strikes a balance where your IEM will be the main source but be colored just enough to tweak it to something possible more to your palate if your stock IEM is not. Using Ragnar as a point of reference, those who may find it's treble to be "too much" may prefer the PB5 due to it's coloration and added warmth reducing treble presence.

The Lotoo Mjolnir was a massive surprise for me at CanJam NYC 2024 but an extremely pleasent one and I'm glad I was able to hear it thanks to Musictecks table and now own it and have the pleasure of listening daily at home! This is truly an end game source that has trumped my expectations for what is possible from such a neutral and transparent source to, at the same time, sound so engaging, exciting and never nearing dry or cold sounding. I hope to put it through it's paces more in the future and try out some full sized headphones on it.

Hopefully this review will help any prospective buyers in their decision making process and let you know if the Lotoo Mjolnir is the right source for you. Thank you for taking the time to read and appreciate any feedback or comments!

And don't forget to check out the Lotoo shop at Musicteck for the Mjolnir and other Lotoo products at https://shop.musicteck.com/collections/lotoo