First brief impressions of Bakoon HDA-5210MK4:
1.
Build: The HDA-5210MK4 is a fairly compact (A4 size) though quite a chunky amp. It's probably somewhat bigger than it looks in photos. You can see difference in size between HPA-21 and HDA-5210 below (and also HPA-01M for the giggles). HPA-21 is notably more compact. Build is tank-like. Everything feels immensely robust and solid, from the output ports to the enclosure itself. Indeed, the enclosure has an interesting sort of texture which is not unpleasant to the touch. In terms of design, I'm a fan, though I can see it being a bit of a niche aesthetic.
2.
Usage: You can read more on the specs
here, but a couple of points. The volume knob - controlled by a metal film attenuator - is a 23-step control. This means, it "clicks" with each step rather than rotating in one smooth motion. In practice it works exceptionally well with planar headphones, though this is not the amp for IEMs. Incidentally, the volume knob has a very satisfying tactility. I believe it's made from bakelite. While there is a notable resistance to each gain step, it's satisfying in hand.
3.
Power: You'll notice the specs say 500MW for current output. I wasn't quite sure this was right, given the HPA-21 is 1W. I looked into this and got the following reply:
"As Bakoon Products founder Mr.Nagai said that 1W current output for a headphone is too much for a headphones, it would be breaking headphones.
He doubts 1W. Please note that Bakoon Products is original SATRI-IC company who provided SATRI circuit as OEM to Bakoon international in Korea. But no more providing.
Mr. Nagai develops all SATRI systems. Thus, I believe current output 500mW is correct number."
In practice, I can confirm that 500mW is more than enough power. On both my Thror and Rognir, I am seldom moving beyond 12pm on the dial. I cannot speak for other planar headphones, but for Kennerton headphones there is an abundance of headroom.
4.
Sound: Let's get to the goods - how does it sound? Some context, I fell in love with the HPA-21 & Thror/Rognir pairing. It was the best headphone pairing I'd heard in terms of pure synergy. There are some combos you hear together and you know they were meant for each other; that was the HPA-21 Thror/Rognir pairing. I'm pleased to say with the HDA-5210MK4 this synergy is even greater. Indeed, everything is greater on the HDA-5210MK4. This is truly a remarkable amplifier on a number of levels:
- The timbre of the HDA-5210MK4 is neutral/linear but incredibly musical. I have a leaning toward this sort of presentation - precise, highly resolving, fast, musical - but I've never heard it articulated with greater coherence than in the HDA-5210. I would not exactly describe this amp as "smooth" if you take smooth to be rolled off and "lush". The presentation on the HDA-5210 is highly resolving, transparent, and very revealing - and yet, absolutely not dry or clinical.
- The timbre itself has the most accurate sense of realism I've heard in an amp. By "realism" I mean the amp produces the timbre of individual instruments in a lifelike way, capturing what is unique about a given instrument/tone (including the voice).
- The sense of authority and dynamics are staggering. This amp has a serious sense of "grunt," which is present on both low and high volume. Some amps come alive when pushed; the HDA-5210 already sounds excellent at low volumes.
- Detail retrieval, speed, imaging, and layering are notably excellent. I had thought the HPA-21 was impressive in terms of keeping pace with complex music, but the HDA-5210 is on another level (spoiler alert).
- The overall presentation also has a very holographic sense of space without being overly diffused. Presentation is immerse and expansive while retaining total coherence.
5.
Pairings. As above, I only bought this amp to use with Thror/Rognir. I did try on some other headphones using the voltage mode, and they sounded very good, but this is not what this is amp is for. Both the Thror and Rognir pair majestically well with this amp. With the Rognir, you get a very punchy/exciting presentation with sublime layering, outstanding extension, and top-tier dynamics. Bass is thunderous and immensely quick. With the Thror, you get a reference presentation with greater linearity than the Rognir. Detail retrieval and imaging are immerse and precise; the HDA-5210 also gives the Thror a controlled but extremely layered bass.
6.
Vs. HPA-21: How does it compare to the much venerated HPA-21? I connected the HPA-21 to a Hugo 2 and the HDA-5210MK4 to a Qutest to even out the odds. The HPA-21 remains an outstanding desktop amp (and also trans-portable amp given it runs on batteries), but the HDA-5210 is in a different tier. Compared to the HDA-5210MK4, the HPA-21 sounds more laid-back, with less authority, and less definition and less resolve. The HDA-5210 has much better control over the overall presentation: everything sounds tighter, crisper, with much better definition. Details pop out effortlessly and both macro/micro dynamics are articulated with more clarity on the HDA-5210MK4. In addition, comparing the two I notice some kind of grainy quality in the HPA-21. On the HDA-5210, there is an absolute clarity even at high volumes with badly produced music. Beyond this, these two amps do share the same tonality/timbre, so if you like the HPA-21, then you will love the HDA-5210.
In sum, kudos and congrats to Akira Nagai on the design and implementation of an excellent amp! I also want to give a shout out to Pat at
War Audio in Australia. I ordered this amp on Thursday (28th) and it arrived today. Excellent to deal with more generally.
This one is a keeper for sure.
