Schiit Mjolnir 3 and Flux Mentor versus my upgraded Cayin HA-3A
I recently had some blasphemous thoughts about simplifying my life and perhaps going back to some of the better and more interesting solid-state amplifiers. Tube rolling can be expensive, time consuming and not without hassle. Life with a solid-state amp is just so much cheaper and easier. To cut a long story short, two amplifiers ended up on my shortlist: the Schiit Mjolnir 3 and the Flux Mentor. Both of these are around the same price (slightly cheaper than a stock HA-3A), and they are both regarded as extremely good value, beating other solid-state amps that cost two or even three times more.
This little write up will be a comparison of the Mjolnir 3 (MJ3) and Flux Mentor from a mostly subjective perspective. I am sharing this in the HA-3A thread, as spoiler alert; my tubes are not going anywhere. I will link this post in the Mentor and MJ3 threads too, as many folks were interested in a MJ3/Mentor comparison.
Mjolnir 3 vs. Mentor:
I have to start by saying these are two very different amplifiers. In my opinion they were built with different purposes in mind, for different people and for different music genres. The only reason they ended up competing so directly against each other (at least here on the forums) is their similar price tag, similarly excellent value proposition and limited availability. (Lead time for a new MJ3 is roughly 2 months, Mentor production is on and off in Ukraine.)
This is not a proper review, so I am not going into all the practical and functional differences, but only focusing on sound. My time is limited, and I have other reviews to work on, so won't mention information which is easy to google.
Let's start with the sound of the Mjolnir 3. Initially, before burning in I found the treble a little harsh and unrefined. Luckily this has improved, and the disturbance completely disappeared after 60-80 hrs burn in time. The Mjolnir 3 has a very fun, dynamic and engaging sound. There is definitely some sweetness in the sound and great tonality which is rare to hear with a solid-state amp and make the listener tap their toes and keep clicking for one more track. Pairing the MJ3 with a good DAC is important, as this amp is very DAC picky. Based on the choice of your DAC, the experience can be flat and uninteresting or super exciting and colourful/energetic.
On the Mjolnir 3, bass is served in one of the tastiest ways I have ever experienced on an amp: it is alive, kicking with superb impact and dynamics. It is not overblown or over emphasised, but present with a lot of life. Listening to EDM tracks on the MJ3 with something like the Caldera is a super fun experience.
Mids and vocals are surprisingly sweet, lifelike and engaging on this amp with excellent tonality. I was not expecting this from a solid-state.
I would classify treble as 'fine', good enough, but in all honesty, there is not much to write home about treble performance. It is not the cleanest, not the most resolving when we compare it to the other two amps in question, but when listening to the MJ3 alone, nothing really feels off or missing from the higher frequencies. At the same time, it can get better elsewhere.
The Mentor is a completely different animal, IMO catering for different needs. It is more technical, more resolving, and a lot more neutral than the MJ3. After the MJ3 it feels like a quality step up in refinement and resolution. There is a much larger space with a completely black background. You can hear details on the Mentor which are not or just very faintly present on the MJ3. The Mentor sounds more like traditional Hi-Fi, its tonality is in line with other higher-end amps. Instead of the unique taste and fun on the Schiit amp, with Flux's offering you get smooth detail retrieval and technicalities in spades.
The Mentor is a mature, extremely well balanced, very neutral sounding and effortlessly technical amp. The coherence, refinement, smoothness, ease of separating busy orchestral music is impressive. If the MJ3 is your fun EDM amp, the Mentor is your perfect solid state for grand orchestral pieces where this amp creates a huge clean space, and you can easily pick up individual instruments in the orchestra and follow them if you like.
If I found treble to be MJ3's weak point, for me personally it would be bass on the Mentor (yes, even after a week of burn in). Not that the bass is not clean and clear, it is certainly high quality and very balanced, but in direct comparison to the other two amps, it is more polite. Sub-bass performance is actually surprisingly good, this amp reaches down to the lowest frequency levels with no effort. Mid-bass however, especially on EDM tracks, could have more muscles for my taste and not just frequency-wise. It is a clean bass with good separation, but I miss the weight, body, macro-dynamics and slam the two other amps offer. With classical or acoustic music this is not an issue at all, but despite the higher resolving capabilities and better overall balance of the Flux, ultimately I found EDM tracks more fun on the MJ3. Listening to the Mentor only, most people won't miss anything from the bass, but when directly comparing to other amplifiers, bass can get a bit snappier, heavier and more impactful elsewhere.
Mids and vocals are nicely presented on the Mentor with nuance, but due to the more neutral tuning I did not find them as engaging as on the MJ3; not to mention the tubes.
Treble is one of the strengths of the Mentor though: it is natural and effortless. Highly detailed but in a realistic and smooth manner. This treble will never-ever be fatiguing to any ears, yet all the details one could ever wish for, are there. If I had to sum up the Mentor in one word, that would be refinement.
(Flux is about to release another amplifier, called the M-Field which is a counterpart to the Mentor with a different, more euphonic tuning.)
I do not think it is possible to pick a clear winner between these two SS amps. IMO the Mentor is more for the analytical listener who loves classical music, the MJ3 for those who simply love to get lost in music and have fun when listening to mostly modern pop or EDM. Calling the Mentor a more analytical amp does not mean it is boring. It has a smooth neutral sound with just the tiniest hint of warmth. The Mentor captivates the listener with effortless clarity.
These two amps are a little bit like a Mercedes S-Class versus an American muscle car:
refined elegance from Europe vs. wheel-spinning fun from America
I personally admire the technical prowess of the Flux, but long term I think I would prefer the more engaging tonality and fun focused tuning of the MJ3 despite the obviously lower resolution. I wish there was a way to combine the overall tonality, fabulous and dynamic bass of the Schiit amp with the high resolution, outstanding balance plus refined and spacious treble of the Mentor!
HA-3A (with GE rectifier, Bendix 6V6GTY and Mullard E80CC)
I have been enjoying this Cayin amp for almost 17 months now. This was my first tube amp, and even with stock tubes I fell in love with the liquid, natural, lifelike tonality. I had swiftly sold my GSX-Mini back then, as I found its soundstage limited, and its timbre quite digital in direct comparison.
Since then, I have rolled many tubes with the HA-3A, slowly but steadily improving its performance. I was not happy with the bass performance of the stock tubes with EDM, but luckily that can also be improved with selected NOS tubes.
What I love the most in tubes versus solid state, is their extremely 'fluid' nature and supremely natural, lifelike tonality. Singers and acoustic instruments simply come 'alive' on tubes versus SS. Same is true for drum notes or cymbals. In addition, tube amps often sound more spacious and have greater imaging and separation.
I also have to add that I only recently started to use my first E80CC tubes in the 3A as opposed to the officially recommended 12AU7s, and the result is impressive indeed. The E80CCs draw more current resulting in a much more dynamic and impactful sound in a much larger space. There is more definition, contrast and depth with these tubes, elevating the HA-3A to yet another level.
The two super-value and unique SS amps were facing this pumped-up tube amp on steroids. With my current tube set (GE rectifier, Bendix 6V6GTY and Mullard E80CC) the Cayin amp retains its fluid and most natural tube magic, but technicalities and dynamics are hugely improved compared to the stock version.
Instead of more words, I created the following little spreadsheet to ponder on. These numbers are not set in stone, they are here just to give a rough idea.
Conclusion:
If I could justify it, I would happily keep all of these amps for different moods, and at the end of the day I could probably live with any of them. Since life is expensive, I do have to choose one and for me it is my upgraded Cayin. This little experiment serves as another proof that tubes just captivated my heart and ears forever. Their sweet and engaging tonality breathes life into voices and instruments: everything comes alive on tubes. It often takes some tweaking, but the right tube amp with the right tubes can also sound technical enough with great spatial presentation and deep, impactful bass.
While I admire the Mentor and enjoy the MJ3, it seems I have just irrevocably become one of those tube guys. If and when I get another amp after my Cayin, that has to be and will be a higher end 300B amp or even more likely, the new Aegis. Not this year though.
Hopefully some of you guys can use some of this information on your own journey. Peace and happy listening!
