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POWER AMPLIFIER ⸜ monoblocks.


Manufacturer: AUDIO NOTE Co., LTD.
Price (in Poland): 110 000 euro/pair

Contact: 242 Shimohirama, Saiwai-ku
Kawasaki, Kanagawa 212-0053 JAPAN


Provided for the test by: NAUTILUS Dystrybucja


translaton Marek Dyba
photo “High Fidelity”

No 235

December 4, 2023

The Audio Note Japan using KONDO brand (named after its founder), is one of the best-known, even legendary, brands producing exclusive, top-of-the-line tube amplifiers, line and phono preamplifiers, phono cartridges and cables in the world. We test the new version of its GAKUOH II power amplifier.

T IS IMPOSSIBLE to walk past Kondo equipment indifferently. I have tested this many times on myself, on colleagues, and I also know it from people who have no more than occasional contact with music. They have a similar effect regardless of the context - amusement and a kind of admiration, and even respect. And yet - they are seemingly nothing particular, just ordinary tube amplifiers, maybe a bit bigger than most other products of this type, but not by much.

Or is it copper, a material that is a hallmark of this company? Visible in the form of the top plate of the Gakuoh II, Kagura 2i power amplifiers and the Ongaku integrated amplifier, it catches the eye. Especially if the unit is turned on and the tubes' glow is reflected in the copper plate. It probably plays some role too, but there is more to Kondo products than this. There's something in the visual design of these devices, in their proportions, in the logo - by the way, a horn speaker is immortalized on it - that evokes such intense reactions. Many companies have tried to copy this style and none, in my opinion, have succeeded.

Or maybe there is something else to it. After all, only some products of this Japanese company have tubes on top. A large number of them conceal them in aluminum housings with distinctive, multi-faceted fronts. There is definitely something to the design. Perhaps it was influenced by the fact that the company's founder, HIROYASU KONDO, was the son of a Buddhist priest, which in turn established his particular worldview. Or not. In any case, Kondo always impresses. The author of Hi-Fi. The history of High-End design wrote:

Kondo saw his devices as if they were Morgan or Duesenberg guitars: in either case, an important part of production is each employee's pride in the resulting work. In the words of the people at Silversmith Audio, in the process "you should give your best, and everything should be done as well as possible." For Kondo, this was only possible through the handmade process.

⸜ GIDEON SCHWARTZ, Hi-Fi. The history of High-End design, Phaidon, London/New York 2019, p. 180.

As he adds, despite financial crises forcing mediocrity, the company's founder, who died in 2006, left behind a purist artistic work and changed audio in a way that resonates in the industry to this day.

Gakuoh II

IT IS THE SAME WITH Gakuoh II power amplifier being tested this time. And maybe even more. It is one of three power amplifiers from this manufacturer, along with the Melius stereo amplifier (below in the price list) and the Kagura 2i (above). Together with the latter, they form a group of monoblocks. Each of these models is based on different output tubes, and they also operate in different configurations, respectively: pentodes EL34 & PP, triodes 300B & PP and triodes 211 & PSE, where PP = push-pull and PSE = parallel single-ended.

What they all have in common, also with the rest of the company's products is - on the circuit side - class-A tube operation, and - on the material side - deep belief in copper and silver. All units, including those based on EL34 pentodes, operate in Class A, and their amplification circuitry is based on electron tubes. They also all have parts of the chassis made of copper, and the circuitry uses silver cables, capacitors with silver facings and leads, and in the most expensive models also silver windings for the output transformers.

⸜ TUBES • All this can be found in the Gakuoh II model. This is a power amplifier that takes the form of a monoblock, or mono amplifier. So for stereo music reproduction you need two. These are all-tube amplifiers, that is, with tube-based input and output sections, and a tube-based power supply. The outputs tubes are directly heated 300B triodes, an absolute classic and "icon" in audio, two per channel, in a push-pull configuration. They output 20 watts in Class A, albeit at 5% distortion; the power of solid-state amplifiers is measured at 3% distortion.

The input section uses two 6CG7 (ECC81) triodes, each driving "its" 300B tube. A single, rarely seen 6072 (12AY7) tube is used in the input. The 300B triodes are manufactured by the Chinese company Psvane and are copies of the legendary Western Electric tubes. The other tubes, on the other hand, come - unfortunately - from Russian manufacturers: Electro-Harmonix (ECC81, 12AY7) and Golden Lion (GZ34). It would be worth considering other suppliers in the future. Let's add that the tube rectifiers work in parallel to improve their current efficiency and work with chokes placed inside the chassis.

A metal cage, supplied in the set, can be put over the tubes to protect them from us and us from them. It is necessary due to regulations in the EU regarding safety requirements. Needless to say, the amplifier looks much better without it.

⸜ PARTS • The manufacturer emphasizes that the Gakuoh II model features a revised the electrical circuit and uses, as he writes, "new generation" output transformers. This is important, because they are responsible for much of the sound of tube devices. They have been enclosed in large cans visible on the outside, just behind the power tubes.

Important to the manufacturer is the use of top Kondo capacitors with silver facings and leads in the signal path, used in top products such as the Kagura 2i, G-1000 and GE-10. Also silver are the interconnects that transmit the signal from the rear-mounted inputs to the input tube, the resistor leads and the windings of the output transformers; the signal cable mentioned is this manufacturer's top model, the Ls-41. Kondo winds the transformers in-house using a technique it has developed.

When we look inside the device all this „wealth” is not as apparent as the description would suggest. And this is because amplifiers working with triodes are, in general, simple devices. That's why you get unfettered dynamics and clarity with them. But this is also a problem, at least for the designers. In a classical amplifier, the errors and weaknesses of one stage are corrected by another. Here there is no such possibility and everything must be perfectly matched from the very beginning, and any change is momentarily audible. Parameters are usually corrected with quite deep feedback, and in Gakuoh II we have it at an extremely low level of 2 dB.

⸜ FUNCTIONALITY • The signal is fed to one of two inputs: RCA or XLR. Both have silver contacts. The amplifier has is an unbalanced design and the balanced input was added only for user’s convenience - right after inputs signals are symmetrized and they flow through the same interconnect working in a quasi-balanced arrangement. Both of them are also active all the time, so when choosing one of them, it's a good idea to close the other with a plug that minimizes vibrations and shields it from the influence of an outside world.

The amplified signal is output via robust Kondo-built speaker sockets. The output transformer offers three taps of the secondary winding - for 2, 4 and 8 ohm, but there are sockets only for two of them - when ordering the amplifier, you can order a pair that suits you better, such as 4 and 8 or 2 and 4. Let’s add that the top of the chassis is made of copper, to which aluminum plates have been screwed from the bottom, sides and front. On the front, there is a large power switch with a red LED, and a small flip switch we can mute the sound with. The amplifier stands on five metal feet.

It comes with a very nice power cable, namely Kondo ACz-AVOCADO. It is two meters long and made of four runs of pure silver wire. The Furutech plugs used in it feature gold-plated rather than silver or rhodium-plated contacts. The first version of the amplifier, the Gakuoh, was unveiled twenty-five years ago, and the Mk II version premiered at the High End 2018 show in Munich (report → HERE). Gakuoh means "king of music" in Japanese.


⸜ HOW WE LISTENED - The Kondo Gakuoh II monoblocks were compared to my reference, the Soulution 710 solid-state power amplifier, and drove Harbeth M40 speakers.1 The initial amplification was handled by an Ayon Audio Spheris III tube preamplifier, but it's worth mentioning that the manufacturer has its own outstanding G-1000i preamplifier.

The signal between the preamplifier and power amplifiers in both cases was carried by Acoustic Revive Absolute RCA interconnect. The amplifiers were powered by Crystal Cable Da Vinci cables, and the signal to the speakers was carried by the same company's speaker cable from the same series (test → HERE). The signal source was the Ayon Audio CD-35 HF Edition SACD player.

The Kondo amplifiers are large enough that they did not fit on the top shelf of the Finite Elemente Mk II rack I use. So I placed them on the floor, on Acoustic Revive RST-38H platforms and RKI-5005 pads from the same company.


⸜ JOHN COLTRANE, JOHNY HARTMAN, John Coltrane And Johnny Hartman, Verve Records/Universal Classic & Jazz UCGQ-9042, "Acoustic Sounds SACD Series III," SHM-SACD ⸜ 1963/2023.
⸜ JOHN SCOFIELD, Uncle John's Band, ECM Records/Tidal, FLAC 24/96 ⸜ 2023.
⸜ KENICHI TSUNODA BIG BAND, Big Band Scale, Warner Music Japan/Tidal, FLAC 24/96 ⸜ 2015.
⸜ BLACK SABBATH, 13, Vertigo/Universal Music (Japan) UICN-1034/5, 2 x SHM-CD ⸜ 2013, more → HERE (PL).
⸜ JAMIE xx, In Colour, Young Turks/Hostess YTCD122J, CD ⸜ 2013/2014, review → HERE.
⸜ HANIA RANI, Ghosts, Gondwana Records/Tidal, FLAC 24/48 ⸜ 2023.

WHAT DO WE USUALLY EXPECT WHEN LISTENING to a 300B power amplifier? Probably most of us will answer that warmth, tangibility, speed, naturalness, and above all beautiful vocals are the expected features.

These are obvious clichés, and some of the most popular ones in the audio world. Although their roots go back no further than the late 1970s, when Japanese companies "reactivated" the tube fashion, bringing this noble mode of amplification back into general circulation.

I know from experience that 300B tubes can play very differently, and it all depends on their application. Because, after all, you will get a completely different performances with Ancient Audio, Haiku (SEnsei 300B SE model, test → HERE) and Thöress (SE300B model, test → HERE) and, on the other hand, Phasemation, Air Tight or Western Electric (model WE 91E, test → HERE(PL), to just name a few amplifiers of this type that come to mind. And all of these brands are excellent at what they do.

One thing is true about this cliché, however: it's one of the few ways, perhaps outside of 2A3, to achieve remarkably natural and palpable vocals. That's why JOHNY HARTMAN's voice from the album he recorded with JOHN COLTRANE for the Impulse! label was so charming. I could actually say: stunning in its reality, but I don't want to flaunt you with hyperbole. 'Charming' says it all.

Hartman, known for his deep baritone voice and specializing in jazz ballads, is wonderfully countered on this disc by Coltrane's soprano saxophone, as well as McCoy Tyner's piano. The saxophone is set up in the left channel, the piano in the right one, along with the drums, and the vocals can be heard, along with the double bass, right up front. And it's a BIG vocal. To be blunt - the Kondo Gakuoh II plays this kind of music in a remarkably, unbelievably natural way. There is no shadow of mechanics in it, we even forget that it is a recreation.

This is helped by the mastery of Rudy Van Gelder, who recorded this disc, as well as the beautiful release on SHM-SACD with material ripped to DSD from the "master" tapes, that is also clear. But none of this would be so great if the system couldn't convey it. And with the Kondo amplifier it does it better than I remember from any playback in my system. Except maybe the Ongaku.

The same was also true of JOHN SCOFIELD's guitar, recorded by Christoph Stickel on Uncle John's Band. It's a new recording, digital, but one that has something we look for in analog recordings, and that is beauty - beauty understood as truth. And the latter comes from the fact that the sound coming to us slips past our disbelief, making us perceive it as natural. That is, one in which we do not recognize a participation of a technique.

This, of course, is an illusion of sorts, it's still a mechanical reproduction, with all the consequences of that. However, the best systems know the trick I'm talking about - their sound is shaped in such a way that everything that usually bothers us in sound is pushed far back, so much so that it is absent. We only notice this when a components appears in the system that is better than the one we have been using. Then it occurs to us that we are talking about a compromise. But at the same time we begin to believe that this new, better component, is devoid of them And so ad infinitum. It's simply audio.

This was also the case with the Kondo amplifier that replaced the Soulution 710 power amplifier in my rig. Maybe not exactly, this is not a zero-sum situation, and the devices turned out to be remarkably similar in timbre and in the way they built the "presented world," so to speak, despite the extremely different techniques that lead to it. But still, both Hartman's voice and Scofield's guitar, and - listened to immediately afterwards - the KENICHI TSUNODA BIG BAND from the Big Band Scale album had a breath, freedom and remarkably natural midrange with the Gakuoh II, one could fall in love with.

With which I’d like to return to the stereotype of the "300B sound". But I do it consciously and with detachment. Because the Kondo does it perfectly. Interestingly, we perceive the midrange with it in such a unique way not because its extremes are withdrawn. The withdrawal of the top and bottom is something that many music lovers even expect from tube amplifiers. They are looking for that kind of sound. And that's because that's when they get the "magic midrange" from even inexpensive tube amplifiers. With the tested Kondo monoblocks, this is not needed.

This is an amplifier that plays with a sound of powerful scale and wide range. Within the constraints of the Harbeth M40.1's low efficiency and current-hungry nature, the scale, dynamics, power - all were superb. And at the same time, the sound did not close in on the midrange. And the treble and bass were clear, active, energetic. Yes, the lows were not as selective and did not have such a clear attack and decay as with the Soulution amplifier, or - even more so - with the Aavik I-880 integrated amplifier. But that's why we choose an amplifier for ourselves, not for measurements or technical data. We decide for what is most important to us.

Sitting quite close to the Harbeths, about 50 cm closer than usual, reading an average value of 79 dB on the SPL meter, with a maximum of 88 dB, I heard no overdrive, which means that the Japanese amplifier has considerable current efficiency. However, it's important to know that in a larger room and sitting farther away from the speakers than I did, you'll have to think about speakers with much higher efficiency. It is important that they have as strong and low bass as the Harbeths. And that's because the Gakuoh II plays a meaty, low-pitched sound. And it is on bass and low midrange that its presentation is built.

When I played the second track on BLACK SABBATH's 13 album ˻ 2 ˺ God is Dead?, momentarily the room became dark and murky. The bass hit low and thick, and the kick drum picked this up, as did the bass played very low. This was partly helped by the release, the Japanese version on SHM-CD, but that's probably not the point. Rather, the point is that Gakuoh II loves this kind of playing. Heavy, massive, full.

This is because it is its "own" sound. Limited, admittedly, by maximum power, because 20 watts at five percent distortion is not much. But these are the watts we often call "tube" ones, because a tube reacts differently to transients than a transistor, it enters overdrive differently making it appear to have much higher power than it does on "paper." That's why the Black Sabbath album sounded powerful, with a kick.

As I say, with the tested amplifier the lowest range is rather soft and more constructed in the head by us based on higher harmonics. And yet it seems solid and massive. This is one of the advantages of this type of equipment. The guitars in the aforementioned track are not particularly jazzy and are set low, which adds to the overall dark allure. The upper midrange was warm, as on previous albums, it was not withdrawn, this is clear, transparent playing. But both clarity and distinctness are something we will hear with any disc. But every time with the Gakuoh II in the system it will be contrasted with depth and fullness.

The electronics with samples, loops, strong production and very low bass contained on JAMI xx's album entitled In Colour sounded beautifully. This English producer, musician and DJ saturated his album on all levels. It's usually the case that cheaper equipment focuses on low bass, "not noticing" that it is brought out high by saturating all sounds with warmth. However, since this warmth built up with small signals, it often escapes, leaving transparent, clean playing, but lacking that what the Kondo showed after just a few drum beats: fullness.

I listened with interest to a few more albums, both on SACDs, CDs and in files, looking for answers to how the amplifier builds space. This turned out to be more difficult to define than usual. After a while, it occurred to me that this device does not "build" a stage, nor does it "present" instruments. What it does I would call simply "saturating the space". Everything that happens between the speakers is tight and there is no room for gaps. It's dense to the point where the bodies of sound sources cease to matter, as they are permanently connected by a kind of "fluid".

And, as I said, it doesn't matter what album we happen to be listening to - Kondo applies this to all recordings. HANI RANI's voice in the ˻ 2 ˺ Hello track from the Ghosts album. came both from the axis in front of me, close to me, and from far away, and also had something like "side bars," to refer to measurements. That is, it had a clear "kernel", it was the one that attracted attention, but it was underpinned by something broader, which made the voice being perfectly blended with the whole presentation.


KONDO GAKUOH II fulfills all the wildest dreams of the 300B lovers. Its sound is natural, incredibly deep and fantastically colorful. The presentation is very fast and dynamic. It's a speed expressed in density and naturalness. Dynamics, on the other hand, builds the diversity of the sound and can't be heard as something independent.

The device plays in a warm way, there's no denying it. This warmth in it comes from a lot of small information, but especially from the saturation of the low tones. The treble is strong and sonorous, so it's not a "closed" presentation. The whole is very coherent, even homogeneous, which I associate - if we were to change tube type for a moment - with EL34 pentodes rather than KT120 beam tetrodes.

And yes - the most important will be the vocals. That's because a strong bass base allows for building large bodies and superbly saturated space. Don't expect selective playing or a highly detailed one. This is not that kind of sound. Everything that comes to us is internally connected by something like a binder, binding the music together into a beautiful, big and colorful picture. Gakuoh II will play any album with any music genre as if it were the one most important album to us. .

Technical specifications (according to the manufacturer)

Nominal output power: 20 watts (1 kHz, 5% THD)
Frequency response: 10 Hz-40 kHz (+0 dB, -3 dB/1 W)
Input impedance: 70 kΩ (RCA, XLR)
Speaker outputs: 4 ohm, 8 ohm, 16 ohm (two of them selectable)
Noise: <1 mV
Tubes: 300B x 2, 6CG7 x 2, 6072 x 1, GZ34 x 2
Power consumption: 120 W
Dimensions (W x H x D): 294 x 284 x 485 mm
Weight: 32 kg/pc.

THIS TEST HAS BEEN DESIGNED ACCORDING TO THE GUIDELINES adopted by the Association of International Audiophile Publications, an international audio press association concerned with ethical and professional standards in our industry, of which HIGH FIDELITY is a founding member. More about the association and its constituent titles → HERE.


Reference system 2022

1) Loudspeakers: HARBETH M40.1 |REVIEW|
2) Line preamplifier: AYON AUDIO Spheris III Linestage |REVIEW|
3) Super Audio CD Player: AYON AUDIO CD-35 HF Edition No. 01/50 |REVIEW|
4) Stands (loudspeakers): ACOUSTIC REVIVE (custom) |ABOUT|
5) Power amplifier: SOULUTION 710
6) Loudspeaker filter: SPEC REAL-SOUND PROCESSOR RSP-AZ9EX (prototype) |REVIEW|
7) Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|


Analog interconnect SACD Player - Line preamplifier: SILTECH Triple Crown (1 m) |ABOUT|
Analog interconnect Line preamplifier - Power amplifier: ACOUSTIC REVIVE RCA-1.0 Absolute-FM (1 m) |REVIEW|
Speaker cable: SILTECH Triple Crown (2.5 m) |ABOUT|

AC Power

Power cable | Mains Power Distribution Block - SACD Player: SILTECH Triple Crown
Power (2 m) |ARTICLE|
Power cable | Mains Power Distribution Block - Line preamplifier - ACOUSTIC REVIVE
Power Reference Triple-C (2 m) |REVIEW|
Power cable | Mains Power Distribution Block - Power amplifier - ACROLINK Mexcel 7N-PC9500 |ARTICLE|
Power cable | Power Receptacle - Mains Power Distribution Block: ACROLINK Mexcel 7N-PC9500 (2 m) |ARTICLE|
Power Receptacle: Acoustic Revive RTP-4eu ULTIMATE |REVIEW|
Anti-vibration platform under Acoustic Revive RTP-4eu ULTIMATE: Asura QUALITY RECOVERY SYSTEM Level 1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RPC-1 |REVIEW|
Power Supply Conditioner: Acoustic Revive RAS-14 Triple-C |REVIEW|
Passive filter EMI/RFI: VERICTUM Block |REVIEW|


Speaker stands: ACOUSTIC REVIVE (custom)
Hi-Fi rack: FINITE ELEMENTE Pagode Edition |ABOUT|
Anti-vibration platforms: ACOUSTIC REVIVE RAF-48H |ARTICLE|

  • HARMONIX TU-666M "BeauTone" MILLION MAESTRO 20th Anniversary Edition |REVIEW|


Phono preamplifier: Phono cartridges: Tonearm (12"): Reed 3P |REVIEW|

Clamp: PATHE WINGS Titanium PW-Ti 770 | Limited Edition

Record mats:


Headphone amplifier: AYON AUDIO HA-3 |REVIEW|

Headphones: Headphone Cables: Forza AudioWorks NOIR HYBRID HPC