Schiit Mjolnir 3 Desktop Class A Headphone Amp

Meet Mjolnir, Thor’s Hammer. In this case a 16 lb. Schiit Hammer!







Class A amps have been one of my favorite types of amps since I started listening with headphones. I have built several, still have a few and when Schiit announced the new Mjolnir 3 I had to get one to test and listen to. Well today I received a unit from Schiit, thanks to Schiit for providing the unit. I get no enumeration from Schiit for anything I write and the unit will be returned to Schiit. All opinions here are my own as always YMMV.

I will state this now and at the end. If you really like to listen to music and forget about the specs and how much power you have or the feedback employed. This amp is for you. Run don’t walk and get one.

If your old school, like products that are built VERY well, are heavy like 16 lbs., simple, powerful, sixteen (16) 10-amp bipolar NPN transistors per channel, and just want to listen to music a lot…. this is your amp. Yup it really is. (oh, that’s a total of 32 output devices!).

So, 16 lbs. of an amp, came in a sturdy box with two plastic foam end-caps and a third supporting piece of this poly foam stuff to support the unit in the middle. A power cord and a simple Schiit users or owner’s manual with the usual Schiit satire…. has to be a Jason trademark…?

When I was in the Army to become a 2nd Lt. I was told that first impressions are a lasting one. Lifting a 16 lb. amp out of a cardboard box well that made a lasting impression on me. This thing is heavy.

This is a photo from the Schiit website. I did not want to take the cover off on the unit. I usually do, to compare with similar units. But this amp is not like anything else out there for headphones at this price point that I am aware of. Typical clean straightforward layout. No wires. No Antennas. Easy to manufacture. Brilliant.




There’s the reason for the weight…”4” weighty devices on the left, the two transformers and two chokes. You can call this a headphone “beast”. Its just an amp, a full Class A amp. All the time. No weird stuff. No plug-in stuff…Simplicity. Built to last. No fan.

Power supply filtering has >20,000 uf for each channel, 2 48VA transformers, 2 chokes, Rails 100v for each channel that are separate and 100 % discrete regulated. The entire amp is discrete.

The obligatory Specs:




Power Consumption: 50 Watts typical. Size: 16”x 8” x 2”

1 Full Watt RMS at 300 ohms not to shabby for your high impedance cans…2 watts RMS at 32 ohms. Nice. The secret sauce here IMO is the Choke inputs…why do I say this?

Well Chokes are old school, they are big and heavy and add cost. As Mike Moffet has said they have been abandoned due to the weight and cost. The choke is about the same size as the power transformer, look at the internal picture (same for Tyr). Chokes store energy, like period capacitor banks, they help provide large reserves of power…which in concert with the capacitors and 32 discrete output devices make this not a run of the mill amp. It’s a “beast”. IMO this is an end game headphone amp. Yes there are many other great amps out there, but there is only one MJ3.

MJ3 has what is called ‘Dual Mono” Well this is a really neat design…. each channel is a total entity all to itself. The only thing in common as Schiit states on the website, is the PCB (circuit board). Each channel has its own power transformer and choke, separate regulation. Simply amazing to me. Old school. Add the choke for old school filtering, smoothing and power reserves…gosh this is almost a perfect storm here for me.

MJ3 is fully discrete, balanced differential. What does this mean? Well here is Schiits description shamelessly copied, I cant say this any better:




Ok so what’s on the Back:





Balanced inputs via XLR, great for your Bifrost. No conversion to SE inside. No funny stuff.
Single Ended Inputs, For SE sources via RCA cables. Converted with Schiit magic to Balanced.
Balanced Preamp outputs, For external monitors or external speaker amps with Bal inputs via XLR cables.
Single Ended Preamp outputs! If you don’t have Balanced devices. RCA.
Power Switch, the old school tried and true power switch “on the back” that we all love.
AC Input. This is where the amp gets its power from.

What’s on the Front:






This part shows how special this amp really is.
Input Select, Up for balanced, down for SE RCA.
Preamp Enable, up to enable, down to dis-able.
Volume, Self-explanatory?
Gain, Up for high (4, 12db), Down for low (1, 0db).
Mode, up for push-pull Class A, down for SE Class A. (considered to be the purest form of Class A). Push-pull gives you more power though. You get to choose what you like with what headphones you use.
Feedback, Up for feedback, down for No feedback. Again, depending on your headphones, hard to drive or not you get to choose which selection performs better to your ears.
Power LED.

In the simple manual provided there is guidance in using the Mode and Feedback selections. For me it was simple to decide what worked best for me and my inventory of headphones.

More on Class A from Jason Stoddard: (Choices, Options, Yup).



One thing I did notice when reading about the MJ3 on the Schiit thread at head-fi.com was that someone mentioned that the unit seems to vibrate? Well I could not feel any physical vibrations by touching the case. But knowing that chokes at some frequencies can resonate…I put my ear on the case, NOT near the very warm heatsinks and did hear the chokes “doing their thing”. Absolutely nothing that interferes with listening. How often do you place your ear on a device chassis to feel vibrations? It’s the “beast” doing its thing. Read the manual and Jason has a funny way of explaining this quirk.



Side Ventilation

I might point out that this amp is not the best measuring amp, nope. But for me its more than measurements. I have proven this over and over in much testing and blind listening sessions. For me is does the gear allow me to sit back, relax and get lost in the music. For hours on end. This amp allows this. In spades. As one “famous” reviewer often states in his videos: “Oh la la” such a device”.

Explanation:
The French phrase oh là là isn't so much an expression as an interjection. It can indicate surprise, disappointment, commiseration, distress, or annoyance. The phrase is used to express any moderately strong reaction to something that was just said or done

Note: I am not going to use a lot of those hundred + flowery adjectives to describe the sound. With so many variables, like your gear (aka the “chain”), difference in human beings hearing, source material etc. Flowery prose is left up to the end user. I will say this “any” of your headphones used with MJ3 will “surprise” you with many Oh la la moments.



What lurks inside the "Beast"?

So how did it work with my stuff. One word. “Superb” ok two words, “Excellent”. For almost all of my critical listening I used high gain, SE Class A, and no feedback. I did try many other combinations but did not honestly notice any real discernable “betterments”. Like many of these options there are real technical differences, but the actual impact of the sound is often very minute and very subjective. YMMV. I also tried both SE and Balanced output connections for connecting my cans. I used two dacs with SE and balanced outs, a Soekris 2541 and a iFi iFi Pro iDSD, and the latest Schiit Modi Multibit 2 in SE.

Turning up the volume full tilt with the music paused the amp if dead quiet, NO hint of any noise with any of my headphones, from 29 ohms to 420 ohms. A small noise when switching from the 2 class A modes. Nothing to be excited about.

The first set of cans were my trusty HD650’s. These are my low-end headphones. The 6xx series has become the iconic standard for headphones for many, many years…. but often lacking compared to other higher performing cans…that said I was stunned at how well the MJ3 allowed these 650s to shine. Well-articulated bass, a open euphoric presentation…the only limiting thing here is the narrow soundstage, but this is not the amps doing…with well recorded material I have never heard the 650s sound so well. I could be very happy with just these cans with this setup…if I did not know how other cans “worked”. 300 ohms, but with 1 watt of Class A power…they really sing very, very well. Kudos MJ3.

Second up were my Audio Technica ADX 5000’s. An often-overlooked headphone, Dynamic drivers, 420 ohms. Very light weight, IMO what the Senn 800’s should have been. Light and Airy sound. These cans some say don’t have any bass, like the 800’s…well I beg to differ with this. With this amp and good material, the bass is there and accurate, it lacks the full thick stuff for sure…but for my listening this is the way I like open airy cans. No issues at all driving 420 ohms here . Listening to Eric Clapton and B.B. King on B.B. King and Eric Clapton..”Help the Poor” is like being there. Great amp. Syrogyra’s “Dreams Beyond Control and Birk’s Law” shows what this combo can do in the jazz bass dept, bass, mids, vibraphone. Great cans…MJ3 outstanding.




ADX 5000’s + MJ3


Third up were my Final Audio D8000 Pros. Planars 60 ohms, One of the finest headphones I have ever used. Keepers. A magnificent pairing with the MJ3. The tonality of Jake Shimabukuro Ukulele is stunningly accurate as well as Tommy Emmanuel’s guitar licks. Bass listening to Brian Bromberg’s “Wood’ is tonally accurate, full and well bodied. Joe Satriani’s “Rubina” made me smile big time. Peter Belasco’s Deeper shows how well the amp and the D8000’s work. They worked very well. Chest rumbling bass. On low gain the volume knob is never over 9-10 o’clock position, on high gain 8-9 o’clock position. Tons of power for the D8000’s. One of the best pairings with these cans.

Lastly were my Rosson Audio Designs Rad “0”. Planars 29 ohms. Again, no noise with full volume high or low gain settings. These were the hardest to drive of my cans on low gain volume at 10 o’clock to noon position. High gain, volume setting was 9 o’clock to 11 o’clock. Absolutely no issue driving them, just the load seemed to require a little more EMF to excite them to my liking. Listening to Alison Krauss on “Hundred Miles or More” was esquisite. Wonderful musical wide open presentation….could listen with this combination for hours.




So, is there anything wrong with the MJ3? Well. Sonically to me, No. Build wise, No. Warranty wise, No. The only things that people might not like is it runs HOT and the power switch is still on the back (seriously)……

So, let’s talk warm or “hot”.

After a few hours of playing I measured the temperature on the two heatsinks. Using a thermocouple attached to the lower top side of the heatsinks and underneath the unit as well. Between the bottom case and desktop. It does run hot. I measured 143 – 146 Deg F on the heatsinks and 130 + on the underneath…With no AC on. With AC on in the same room at 76 deg F, the temps went down to 129 deg F on the heatsink and 125 degrees F on the bottom case. Looks like the bottom case is close but a slight differential here. The bottom may actually be part of the heatsink solution ?



Fancy Old School Temperature Measuring Device


Bottoms Up!

Ok so what does this mean. Well it doesn’t invalidate the 5 yr. warranty and Schitt states is not worried and has other considered hot running units (like the OG Asgard) out their working for 13 yrs. later.

Having it next to me I was not aware of any excessive heat, even when placing my hand over the heatsinks. Touching them is another story. Be careful, they are hot. Just like tube amps not a good place to stick your tongue on!

So, some will not like this, but really tubes are fine?

In summary:

Any modern headphone will shine with this amp. A Full Class A all the time amp. A wonderful old school choke input amp that exudes quality and build. Simple elegant design. Musical. A really special amp amongst other good amps. So many options and choices to play with.

If you really like to listen to music and forget about the specs and how much power you have or the feedback employed. This amp is for you. Run don’t walk and get one.

They won’t be around for long.

See I told you I would say this again!

Alex



Note I did a comparison session with one of my favorite other brand Class A amps. The PassLabs HPA-1.

When level set they sound very similar. Different yes. One is warmer IMO that the other. Either one would be fine here. Price wise that’s another story. MJ3 is much more affordable. Great choices here. But look who is on top!



Godzilla meet Thor's Hammer!