Schiit Audio Mjolnir 2

rfernand

100+ Head-Fier
Natural, detailed, and wide: get lost in your music. And then roll tubes.
Pros: Tubes or solid state with LISST. Seems to drive every headphone with ease and still has gas left. Excellent balanced performance. Really good single-ended output. Quiet.
Cons: Requires more real estate than you may think. Careful when switching tubes: you may lose them inside the unit.
This headphone amp is fun, refined, and versatile, but it seems to have a very specific listener in mind to justify its price.

If this were a car, I’d call it a Grand Tourer: plenty of power, luxury, and comfort for loooong rides. But neither this amp nor Grand Tourers are for everybody. Clinical listeners may be better served with more neutral amps, of which there are plenty and much cheaper. This guy is for listeners who like just a little bit of warmth, a fun soundstage, and more importantly, have their entire chain balanced.

The amp’s versatility comes from also serving single-ended headphones very well, and allowing you to roll tubes and change its voice a bit. If that’s not your thing, stick to the stock tubes. You’ll be fine. I had very good results with some JJs, Electro-Harmonix, and Phillips Miniwatts, with the latter being the best performing for me.

The device’s ergonomics are not perfect, but not show stoppers. In particular, one must be careful when replacing tubes especially if new to that game. If a tube slips from your fingers you will have a fun time fishing it out of the unit. If desktop space is precious for you, this amp is definitely on the “almost too large for the office” size. The power switch placement seems to annoy three people on the planet who have posted about it a thousand times; If you think you will be the fourth, Godspeed.

In an attempt to understand it better, I had it hooked to an Yggdrassil A2, a Bifrost, and a Gungnir (all Multibit), as well as a Pro Ject Stream Box 2. If you know these DACs and like what each does separately, Mjolnir 2 will not subtract from the experience. It does mellow out the Pro Ject (for the better), which is very sensitive to your choice of filter. If you’re a Schiit-head, you may find that Gungnir strikes the best price/performance match for Mjolnir 2.

Pretty much every headphone I have was happy with this amp, and the amp had plenty of power left. Opinionated cans (such as Grados) are well supported so they express their signature sound with gusto. If I want to enjoy a session with LCD-X, I have to use the Roon built-in profile for them, otherwise they are way too clinical and distracting. I need no such thing with Mjolnir 2 because the amp’s characted is not neutral and it mellows out the LCD-X. HD6xx are still veiled, narrow, and if anything become a tiny bit more relaxed but still enjoyable.

You can get an idea of what I test stuff with by looking at my test playlist. If your style of music is not there, my experience may not be as informative to you. At the time of review, my hearing is about 20 Hz - 17KHz.

With Gungnir and a bunch of cans I know well:
  • Detail: Plentiful and very natural sounding. The quiet parts are quiet. There is no sharpness around the details: the overall presentation is very natural, relaxed, and fluid. Never muddled or too warm. Nice, precise
  • Soundstage: spacious. Lets headphones do their thing.
  • Bass: Precise, full, and not exaggerated.
  • Voices: Fantastically human - at CD quality, some opera recordings from the 70s/80s are hard to render well. So if you know a particular tenor or soprano well, you’ll hear them in this rig in a fairly natural way.
  • Highs: Never sharp or edgy. Present and detailed enough.
  • Instruments: Superbly rendered and placed. In “The End” (The Beatles, Abbey Road, Giles Martin’s remix) you will notice this clearly during Ringo’s drum solo. Ringo’s tuning on his kit went low by this time and it can feel syrupy in some systems (or hang too much). With Gungnir/Mjolnir 2, you will get a very natural reproduction!
  • Overall: This is a very smooth amp, presenting the sound with class and a certain casual elegance. Pure sprezzatura.
Sadly, Schiit discontinued Mjolnir 2 in early 2021, and had stopped selling LISST (the solid state “tubes”) quite some time before then. You can find used Mjolnir 2s for under $700 on eBay every once in a while. If you like slightly warm amps (or as I call them, “pleasant”), enjoy tube-rolling, and already have balanced end-to-end, this amp is a no-brainer. Get one before they become cult items. After all, the Jaguar E-Type was also discontinued: It was not that expensive, but it was not selling well and was becoming hard to manufacture… and look at them now.

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watchnerd
watchnerd
I just took mine out of the closet and dusted it off after 4 years of non-use.

I had forgotten how good this amp is.

After first testing with same basic EH 6922 tubes (in case things weren't so healthy after years in the closet), I've just put in a NOS pair of Philips SQ E88C / 6922. I'm not sure if they're "Mini Watts" or not.

I've got a box full of about 14 pairs of other NOS 6DJ8/7DJ8/7308/etc to work my way through, from Siemens, Mullard, Tungsram, Brimar, Toshiba, Amperex, Reflektor, Telefunken, etc.
Adnan Firoze
Adnan Firoze
@hikerpunk Recently acquired an MJ2 but never saw your comment before. As a metalhead, I dunno why but I got a good deal on a matched pair of Philips miniwatts and my mind is blown bro! You are spot on. I literally came here to make the comment you beat me to it. \m/
JohnnyOps
JohnnyOps
Heck yes. My Mjolnir 2 sits there with my Gungnir MB on my desktop, year-in, year-out. Have gone through many many headphones, still spend most of my time with the HE-5xx, which is amazing to me. Roll some of the tubes I've bought over the years occasionally, most of my time with Amperex Bugle Boys I got when they were less ridiculous than now. But mostly just enjoy the rig.

Also, have my gungnir RCA outs feed a ridiculously small Nobsound "50w" amp driving old Paradigm Atoms when I feel like going nearfield. It's just a great simple desktop rig. But the RopieeeXL -> Gungnir MB -> Mjolnir 2 is the core of it.

bosiemoncrieff

Headphoneus Supremus
Pros: versatile, ridiculously powerful, dynamic, LISST, quiet
Cons: stock tubes, tube extraction, this genius lost a tube in the amp for 5 mins :-)
First review, guys!
 
Intro
 
Update: I've raised my rating from 4.5 to 5 stars after rolling tubes. The amp, with the right tubes, pairs well with my HE-6s playing most of my music, and I retract my criticism of muddiness. Bifrost Multibit helps, too.
 
I've owned my Mjolnir 2 for several months, and it has been my only amplifier other than Vali. I feed it with my uberfrost multifrost and generally 256kbps audio on up to lossless. I have used it with stock tubes, Amperax 1968 Orange Globes, and LISST. My musical tastes are almost entirely classical—Beethoven, Wagner (see avatar), Brahms, Mozart, Bach, Verdi, Puccini, Schubert, Schumann, Bruckner, Haydn, Mendelssohn—with the rare excursion to top 40 pop—Gaga, Jepsen, etc.
 
Most of my time with it has been using the HE-6 and HD-800, though I have also heard the HD-600 and Q701. Those low-to-mid-fi headphones are simply not as interesting to me as HE-6 and HD800, so they've remained mostly in the closet. HD800 edges out HE-6 in David Mahler's battle of the flagships, and indeed, although the HE-6 does not receive sufficient power from MJ2 to provide a fair comparison, HD800 continues to be overall my favorite pair of cans, likely for its classical prowess.* The comparison is fair, and both of these highly neutral headphones perform well: the HD800 sound is staid and luxurious, like a Bentley, with a wider soundstage set back from the stage by eight or ten rows; the HE-6 is like a high-end sports car, more immediate, visceral, tactile, more 'fun'.  Most of MJ2's power, I should note, comes from the balanced output. What makes the power especially impressive is how quiet Jason has managed to make it, even with tubes. Low gain, 10 o'clock, Amperax '68 tubes, and I hear no hiss in Alfred Brendel's 1976 Moonlight Sonata with HD800.
 
*Although the HD800 has a bad rap with pop (and other "bright") music, after upgrading from a delta-sigma bifrost uber to a bifrost multibit, I found Lady Gaga and Carly Rae Jepsen more pleasing on the HD800 than the HE-6.
 
The raison d'être for Mjolnir 2 is versatility. Yes, it is reasonably powerful, but the flexibility to run both balanced and single-ended inputs and outputs, to adjust gain (+18 decibels), and to roll not only a wide variety of tubes but Schiit's revolutionary linear, integral solid-state tubes (LISST) makes a compelling case for Mjolnir 2 being the most versatile headphone amplifier from any OEM to date. I acquired the 1968 Amperex Orange Globe 6DJ8 ECC88 tubes and have had excellent results with them. Though stock tubes sound acceptable with many headphones, for HE-6 they are inadequate. If you plan to use tubes at any time, I would order the amplifier with LISST and forego stock tubes. LISST is well implemented and pairs well with many handphones though not the HE-6.
 
The design of the amp is spartan but enables Schiit to keep prices down. One pitfall, which surely was partly my fault, was when I was installing my '68 Orange Globes for the first time. I didn't get the pins lined up perfectly, and the tube slipped into the amplifier itself. It took five minutes of rolling the tube around the upside-down amp before I could grip it and pull it to safety. In short, don't let your excitement for tubes allow you to make careless mistakes.
 
HD800
Mjolnir 2 drives the HD800 effortlessly. With tubes, it renders orchestral music exquisite, sublime. The John Eliot Gardiner Missa Solemnis is at times thrilling, muscular, the brass fully articulated, and at others delicate and full of charm. The solo violin that enters in the Sanctus to represent the holy spirit could have been in front of me. There is none of the smear that I heard in Vali here, just highly euphonic music rendered with an incredible amount of detail. The famous HD800 soundstage is coherent and ably conveyed; the imaging is excellent. Strings sound accurate, human voices (solo and chorus) are transparent, timpani rumble—they all sound as they should. Piano, too, is substantial, robust, and reasonably clear (it is perhaps the hardest instrument to render accurately). The '68 Orange Globes are richer and more accurate than stock tubes.
 
LISST takes the detail retrieval up a couple of notches and the wetness of the sound down by something like the same margin. I find myself listening to tubes for three or four weeks and then switching to LISST for the same amount of time, and then switching back. Ultimately I like the tubes better, and intend to get into the tube rolling hobby in time, but as yet the process is just one element of audiophilia that I'm saving for a future day. LISST are regarded as a less compelling implementation of solid state than liquid carbon, or indeed (perhaps obviously) the mighty Ragnarok. I have heard neither of these, and include the remark for the sake of completion. Although there is some consensus about solid state having greater high and low extension, classical music has not seemed to try either of these extremes sufficiently for me to note a difference worth putting down here.
 
The sound curve sounds fairly neutral to my ears, but they are hardly 'golden' so I will simply say that I hear no exaggerations that diminish the quality of the music. 
 
HD800 Impressions ('68 Orange Globes):
- Nilsson/Corelli/Maazel Tosca: HD800s are lovely. Some of Nilsson's upper register has traces of sibilance, but vs. LISST it's much reduced. On low-gain, 1:30 is plenty loud. Bass (esp. with slight eq to raise bass and lower treble) is robust and highly resolving. Loving the brass, sweet woodwinds, buttery strings, thumping Timpani.
- Gilels Waldstein sonata: Piano, living up to its reputation, is hardest instrument to record well. Midrange somewhat hard to make out during complex passages at high volume, i won't say smeared but undifferentiated. Sibilant at volumes above 10:30—everything more pleasant at lower volume, and indeed during less complex passages. Treble crisp and lovely. 
- 'Ad Un Guardo, A Un Cenno Solo' from Haydn's Orlando Paladino, Dorati conducting: strings seem to have tactility, nice voice but meh recording.
- Argerich and Kremer, Beethoven Violin Sonata 5: Very well recorded. Violin is pure and effortless, entirely grain-free. Piano (depending on EQ and volume) is crisp, substantial. Soundstage is kind of non-existent but with two instruments that's to be expected.
- Karajan Bruckner 7: tight, liquid bass, exquisite strings. 
- Karajan Bruckner 9: pizzicato has the utmost realism, extraordinary lifelike decay. Entirely free of sibilance. Holographic soundstage, woodwinds in particular are utterly natural. 
- Solti's Studio Tannhäuser (Act 2): brilliant soundstage—the climax of the entry of the guests to Wartburg is just unspeakably wonderful. lush but tight and precise strings, extremely clear and transparent. Incredible detail retrieval. This recording engineer knew what was up.
 
 
HE-6
Although my initial review criticized the Mjolnir 2 for muddiness with the HE-6, I've since purchased '68 Orange Globes, and have found my previous criticisms misguided. Not only is sound much clearer, but I've begun experimenting with low gain. Yes. You can pick your chin up off the floor. With the volume pot at max and the gain set to low, there is sufficient power adequately to drive the Vienna Phil playing Wagner to medium-high levels. Never painful, but not what anyone could call quiet. I turned it down closer to 3pm at one point. Yep, hell froze over. On high gain, 2:30 is quite loud, with plenty of headroom left.
 
HE-6 sounds quite good. Get a Beethoven cello sonata out, and MJ2 provides ample power to hear the bow drag across the string, the hammers of the piano attack their corresponding strings. Bass in pop songs is more responsive than in the HD800, but you all knew that. For vocals in particular, the HE-6 is exemplary.
 
The $64,000 question is with orchestral music. By comparison to HD-800, nearly every headphone comes up short in instrument separation and airiness—perhaps the K1000, original omega, SR009, and Orpheus successor excluded (I have heard none and speak only from reputation). The soundstage question is one of transducer rather than amp. While the soundstage is nowhere near as wonderful as HD800, the effect of large orchestras and choruses only rarely verges on muddy, and in general impresses me a lot. Naturally bad recording engineers, who don't make the most of mic placement and mixing, can make muddy and congested recordings, and even in the last thirty throughly digital years, the quality of studio recording varies enormously. Though HE-6 pairs poorly with the stock tubes, I have enjoyed excellent results with the '68 Orange Globes. I am less impressed by the pairing with LISST.
 
I recommend the pairing for HE-6 enthusiasts who want a compelling amp on a budget and can acquire third-party tubes (please visit the Mjolnir 2 thread for recommendations, there are many wonderful ones by much more experienced tube aficionados than I). I have not heard HE-6 with any other amplifier, and make comparisons only to the SQ of the HD800. The HE-6 thread has plenty of contempt for Mjolnir 2, but not having heard any other amp, I can neither confirm nor deny these impressions. I like the sound a lot, and do not perceive difficulties with thick orchestral writing except rarely, and this is usually the fault of the recording engineer.
 
A few HE-6 impressions
Stock tubes:
- I'm listening to the Argerich Haydn D Major Concerto. The piano is unpleasantly sibilant in the upper registers. The orchestra is mostly fine. 
- I'm listening to Perahia's Mendelssohn G Minor Concerto. The piano is fine. Pretty sure this was a recording engineer problem. Turned it up—treble is grain free :)
- I'm listening to Zdzislawa Donat sing the Queen of the Night in James Levine's 1980 Studio Magic flute. Occasional sibilance. Not bad. Especially on the high B flat in O zittre nicht (more than other notes above and below).
- I'm listening to Vogliatemi bene from Leinsdorf/Moffo's Madame Butterfly. The tenor sounds natural and transparent, as does Moffo, though not quite as buttery (criticism of singer perhaps more than of headphone/amp). This finale to act 1 would qualify as a dense orchestral passage, but it is rendered quite well. Less air around instruments than HD800, and less precise soundstage, but clear rendering of details. I'm impressed.
- I'm listening to Fritz Wunderlich perform Beethoven's "Adelaïde." He sounds better than piano—much more real, transparent, smooth. Piano sounds a bit off tonally, sibilant, but also distant and muted, which is a weird and not flattering combination.
- I'm listening to Solti's Walküre prelude from the Vienna ring. Strings sound very natural, energetic, intense, palpable, tactile. Brass is compelling, mostly transparent. Timpani sounds good. Crescendo got a bit muddy to listen to—but maybe that's what it's like to be submerged within the orchestra pit rather than set back a dozen rows ala HD800 and their angled drivers. With fewer sections playing, much easier to listen to. Solti's engineer makes good use of his soundstage. 
- I'm listening to tenor James King sing 'Siegmund Heiss Ich' from the same opera—the finale to act 1. Some v slight sibilance in his voice. Strings continue well. Low brass nice, high brass somewhat bright, one moment of harshness registered. Overall very pleasing throughout.
- Nilsson at the end of Act 1 of Böhm's Bayreuth Gotterdammerung ("Welch Banger Traume Maren" to the end). Exceptionally good dynamics. No sibilance. Orchestra tight but substantial. Yes, clearly a live recording, but good timpani thump, woodwinds. Strings ok—most errors due to miking/engineering. Nilsson's slight shrillness is her cross to bear—not MJ2 or HE-6—but the voice sounds natural in the utmost. At 3:30 on the volume pot (high gain) she could be standing 10 feet from me. Human voice consistently best thing HE-6s do. Surprisingly good at imaging brass.
- "I really like you" by Carly Rae Jepsen (Emotion): HE-6 firing on all cylinders. Jepsen's voice is effortless, smooth, clear. Goes from whisper to fortissimo without trouble. Cymbals crash naturally, bass is tight, deep, precise. Renders the tactile energy of the song impeccably. Addictive. With Orange Globes slightly more euphonic. Pop doesn't require the hand-holding with tubes that classical does.
 
'68 Orange Globes, low gain(!):
- "Traume" from the Wesendonck Lieder (Measha Brueggergosman; Franz Welser-Möst: Cleveland Orchestra): truly sublime vocals, nice orchestra 
- Solti's Studio Tannhäuser (Act 2): strings are robust, tactile, visceral, and exceedingly realistic. Bass is lush, impactful and much more satisfying than HD800. Dernesch sounds very good—headphones were always best at human voice, no different here. Chorus is thrilling but not muddy. Soundstage is not HD800 but compelling, good layering of brass. Trumpets glorious. Woodwinds transparent and almost euphonic. Not as technically 'good' as the HD800s—the HD800 has a beautifully wrought cohesive 'whole'—but more satisfying in tone and more immediate and dynamic...but this isn't a headphone review lol.
- Benedictus from Beethoven's Missa Solemnis (Philippe Herreweghe & Chœurs De La Chapelle Royale Et Du Collegium Vocale Gent & Orchestre Des Chaps-Élysées) - violin is rendered beautifully and transparently. Vocals too. As solid as the orchestra sounds, I'm becoming persuaded this headphone, at any rate on this amp, is better for chamber music.
 
 
Conclusion
The amp is dynamic, resolving, flexible, affordable, and ​blows me away in terms of power. I recommend it enthusiastically. You may well find it an end-game amp.
reddog
reddog
A sweet review, The MJ2 is a very good amp.
prismstorm
prismstorm
How hard is the MJ2 working (is the gain switched on, where the volume knob is turned to, SE vs balanced) to drive the HD800 to great effect? Is there ample 'headroom' left?
 
Save for except the HD-6, do you think it can drive all other headphones on the market (LCD-4 included)?  
bosiemoncrieff
bosiemoncrieff
I drive HD800 balanced, low gain, anywhere from ten to two (nine when i'm dozing). There is ample headroom left.
 
I have never owned any audeze product, except the vegan pads for the HE-6, so I must refer you to the exemplary Mjolnir 2 thread; I have no data or experience to share, and my guess would be as good as yours.

Mediahound

Headphoneus Supremus
Pros: Amazing flexibility, plenty of power, dynamic sound
Cons: It can get pretty darn hot when using tubes (which is normal for tube amps)
This is one of the only (if not the only) balanced hybrid amps available on the market that allows you to swap between tubes and full solid state (full solid state is achieved via Schiit's new LISST solid state tubes).
 
It offers plenty of power to drive virtually any headphone yet is also quiet enough for in-ear monitors! It has both balanced ins and outs as well as preamp outs so it's a great all-in-one which can be used with powered speakers and headphones. Note however there is no switch to turn off either the headphones output or the preamp outs, they are each on all the time so when switching to speakers, I just unplug my headphones and when listening to headphones, I turn off my powered speakers.  
 
The sound of the Mjolnir 2 is engaging and detailed. I typically prefer the tube sound however the LISST solid state tubes are really a neat invention. Solid state will always provide a bit more dynamics, low-end bass thump and high end sizzle than tubes, which are more midrange focused and smooth. But being able to swap between the two on a whim is really neat. That said the LISST's sound a bit more grainy and bright than some other solid-state only amps. 
 
Using the Mjolnir 2 balanced with both the Sennheiser HD800 S and the Audeze LCD-3 (as well as using the RCA preamp outs to my powered desktop speakers), I could find absolutely no fault in the sound. It has plenty of power to spare and sounds quite detailed, engaging and musical. As an example, I did a direct A-B comparison to the Cavalli Liquid Carbon and the MJ2 offered up more detail, every time. Switching to the Liquid Carbon just sounded more muffled and I found myself wanting for the MJ2. 
 
As per usual, the Schiit build quality is excellent and it stacks perfectly atop my Gungnir Multibit DAC. The stack has a bit of a Bauhaus design which is something I really like. Note, the MJ2  definitely runs hot if you use tubes so that is something to be aware of. Do not put anything on top of it and use in a well ventilated area (not in a stereo cabinet for instance). 
 
If you're looking for a balanced tube amp, the Mjolnir 2 is going to be hard to beat at this price point. It's a reference quality amp that I can find very little fault with no matter which genre of music I play through it. It get's an easy "recommend" from me!
shultzee
shultzee
Spot on review.
Mediahound
Mediahound
bosiemoncrieff
bosiemoncrieff
As I reread your review I begin to appreciate the virtue of concision—one which I don't share...
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