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Integrated amplifier

A-2 SE

Manufacturer: CSR INTERNATIONAL Ltd.
Price (in Poland): 24 000 PLN

Kontakt: 33-4, Sagamiono 5 chome
Sagamihara-shi Minami-ku
Kanagawa-Pref. 252-0303 | JAPAN |


Provided for test by AUDIOPUNKT

SoulNote is a Japanese company, founded in 2004. its founder is a former engineer, one of the directors of Marantz Japan, Mr. Norinaga Nakazawa. It specializes in solid-state amplifiers, phono preamplifiers and digital sources from the medium price range. We test its largest integrated amplifier, the A-2 SE.

oulNote is a relatively small brand, and its products are made in Japan, in Kanagawa Prefecture. It belongs to the parent company CSR, along with another high-end brand, Fundamental. CSR stands for Corporate + Social + Responsibility, which reflects well the spirit of its founder, Mr. Norinaga Nakazawa-san.

Norinaga Nakazawa-san | The name doesn’t ring a bell? - That’s good, until recently engineers working for large concerns were nameless, teamwork was all that mattered. Exceptions to this rule - see, recently deceased, Mr. Ken Ishiwata, representing the Marantz brand - were just exceptions, nothing more. Anyway, they seem to have been created for us, Westerners, for whom individualism is the supreme value.

In recent years, however, something has changed in this matter, perhaps under the cultural pressure of the Anglo-Saxon world, but only a little. Japanese creators, artists and engineers - in audio industry is usually one and the same person - they are still hiding behind their products. It is no different with Mr. Nakazawa. And there would be something to talk about. I mentioned Marantz - and not by accident, because his story is closely connected with this brand.

Saul B. Marantz, an American, a Jew of Polish descent whose parents came from Cracow, founded it in 1953. Already in 1964, after over-investing in the top 10B radio tuner, he had to sell it to the Superscope. He remained as a director and retired four years later. Probably not by accident. In the same year, mid-price Marantz production started, undertaken by the Japanese company Standard Radio Corporation, which changed the company's goals and perception. In 1972, Superscope founds Marantz Far East to sell products in Japan. In March 1975, the name Standard Audio Corporation was changed to Marantz Japan Inc.

Mr. Nakazawa was one of the engineers who worked at Standard Audio Corporation in the research and development (R&D) department. He developed many important technologies and solutions there and eventually became its president. In 1982, as part of Marantz Japan, he refined the design of a high-class cassette tape deck, and also oversaw the design of the company's iconic CD player, the CD63 model. There are many more products with his "signature", both in the field of digital sources and amplifiers. For example, he was a pioneer in Japan in the use of gain circuits without feedback.

In 2004, the D&M Holding was formed, which included the Denon and Marantz brands. Mr. Nakazawa and 50 other engineers bought out their shares in the company, together with patent rights (management buyout) and on June 30th 2004 they founded CSR, Inc. together.

The first device presented by the company was the Compact Disc da1.0 player, with an output stage and power supply without feedback. A year later, it was joined by the integrated amplifier SA710B, also with an amplification circuit without feedback.

| SoulNote A.D. 2020

As soon as the SoulNote brand reached Europe, we tested the SA300 CD player at "High Fidelity" and three integrated amplifiers: SA300, SA710 and SA730. I liked the devices very much because they realized the vision of sound close to mine. Therefore, with the help of a CD player and the company's amplifier, in 2017 we carried out a series of presentations under the common name Audio Tour De Pologne 2017, organized by Pylon Audio, Fezz Audio and SoulNote distributor, Warsaw's Audiopunkt.

Then nothing happened for some time. In 2018, if I am not mistaken, there were information in Japanese magazines and, as a consequence, also tests of new SoulNote products. The devices looked great. I remember my excitement very well while browsing the issues of the quarterly Stereo Sound. And this is because they were devices designed as a step up from the "SC" and "SA" series, they also looked great, also because of their "architecturally" shaped fronts.

However, these devices did reach Europe, and therefore Poland, only at the end of 2019. It turned out that it took the the most time to to get all its products approved or in compliance with European regulations. The first one we get is the integrated amplifier A-2 in the SE version. In Japan, the "A" series includes also the A-1 and A-0 amplifiers, that in the hierarchy are lower models than A-2, E-2 and E-1 phono preamplifiers, D-2 and D-1N digital-to-analogue converters as well as two optical audio players: the C-1 CD player and the powerful, beautiful S-3 SACD player.

| A-2 SE

The A-2 is a classic, full-fledged integrated amplifier. It features no digital inputs - these are available in digital players and D/A converters from this company - there is also no Bluetooth or internet connection. It offers a high output power - 100 W at 8 Ω and 200 W at 4 Ω. When bridged it is capable of delivering up to 400 W (8 Ω).It is a large, heavy and well built device. Its chassis is made of aluminum, and the sides are decorated with wooden elements, referring to the 1970s. But not quite - their appearance along with the front panel give an absolutely contemporary look, referring to a Scandinavian design.

Front and rear | There are two knobs on the front panel - input selector and volume control. The input selection is indicated using small LEDs and the volume level is shown on a large alphanumeric LED display. There is also a power switch with its diode. There are as many as six line inputs, of which three are balanced XLR and three unbalanced RCA; XLR inputs are wired according to European standard (pin 2 = hot). The A-2 SE is a fully balanced design. This is rare even in very expensive products.

BTL mode | Mr. Nakazawa-san used the balanced construction not only to reduce noise and distortion, but also in a different way. I don't know if you remember, but ten years ago Marantz proposed an upgrade path for their integrated amplifiers other than everything we knew. The classic solution is to buy an external preamplifier and use the integrated amplifier as a power amplifier, or to buy different power amplifier and use the preamplifier section of the integrated.

In A-2 SE, just like once in Marantz devices, we get a different option. On the back of the A-2 SE there are two switches, with which we can choose one of six (!) modes of operation of the device. It can operate in stereo or monaural mode. In each of these modes it can be a stereo integrated amplifier, a preamplifier, power amplifier or bi-amp integrated. The most interesting are the monophonic modes. You need to buy a second, identical amplifier and we will get a real dual mono amplifier - we connect the signal from the left channel from the source and left speaker to one A-2, and the right channel from the source and right speaker to the other.

| Technology

This is a fully solid-state amplifier with no NFB. It is, in fact, a power amplifier with an input selector and an attenuator based on relay-switched resistors. Its current stage works in class AB, in push-pull mode. Darlington circuits were used there, consisting of four small, shielded transistors in the input stage and another four, larger ones, in the output. All sections that could have been skipped without affecting safety were eliminated. This resulted in a very fast amplifier with a wide frequency range (up to 250 kHz), which is based on a very large power supply, with a 600-watt transformer and several dozen small capacitors.

I started this description pointing out the looks of this component. It is completely subordinated to the mechanical design - it is an amplifier with an extremely refined structure. Its base is an aluminum chassis to which aluminum, ribbed plates are screwed. The top wall is double and consists of a steel, perforated mesh and an aluminum frame. The mesh contacts the housing only in three points and is not permanently bolted (it "floats"). Some audiophiles unscrew the frame completely - similarly do the engineers remastering SACDs for Esoteric, who take the top wall of the clock off.

The amplifier stands on three metal, low spikes - two at the back and one at the front. The rear ones are screwed to the bottom, and the front one is directly attached to the platform on which the power transformer is located. This is to help in the best transmission of its vibrations to the ground.

Remote | The "Remote Commander RC1000" remote control is common to the entire SoulNote range. It is plastic, but has a metal, aluminum top. The buttons are rubber, but they operate quite well. With its help, we can control not only the amplifier, but also CD and SACD players, as well as D/A converters.

SoulNote in "High Fidelity”
  • TEST: SoulNote SA730 | integrated amplifier
  • AWARD | BEST PRODUCT 2015: SoulNote SC300 + SA300 | Compact Disc Player + integrated amplifier
  • TEST: SoulNote SC300 + SA300 | Compact Disc Player + integrated amplifier
  • TEST: SoulNote SA710 | integrated amplifier

  • Recordings used for the test (a selec- tion)

    • Andrea Amati Carlo IX. Le Origini del Violino, wyk. Federico Guglielmo, MV Cremona MCV 018-45, CD (2017)
    • Art Pepper, Art Pepper Meets the Rhythm Section, Contemporary Records/JVC VICJ-42524, K2 CD (1957/2006)
    • Krzysztof Duda, Dudaskalia, Soliton (płyta jeszcze się nie ukazała), 2 x Master CD-R
    • Maroon 5, Red Pill Blues, 222 Records | Interscope 6705300, 2 x CD (2017)
    • Radiohead, OK Computer. OKNOTOK Edition, XL Recordings/Beat Records XLCDJP868, 2 x Ultimate HiQuality CD (1997/2017)
    • The Modern Jazz Quartet, Pyramid, Atlantic Records/Warner Music Japan WPCR-25125, „Atlantic 60th”, CD (1960/2006)

    Mr. Nakazawa-san is not slavishly attached to the technologies he uses. That is why his earlier amplifiers worked in class A, AB or D. But this, even for such a sectarian industry as perfectionist audio - is quite normal. The surprise for me was that all these amplifiers sounded in a very similar way. I mean, they had a consistent theme, they followed the same vision, but in different ways.

    The A-2 SE fits this story perfectly. This is another SoulNote amplifier that sounds in such an incredibly natural way, so that one would like to say that all others sound mechanical in comparison.

    This is not so, it is a great simplification, but it is just such a taste that remains on the tongue when you listen to several CDs with it. I think that the reason for this is a slight "tightening" of elements that make the recording sound natural. This is not perfection, but rather a "perfect imperfection," as the Japanese call the highlighted flaw of a beautiful object.

    It is a warm, rich and saturated sound. In fact, it reminds, in a really unique way, the character of my system, consisting of the Ayon Audio preamplifier and the Soulution power amplifier. I started listening from the Master CD-R with unreleased Krzysztof Duda material titled Dudaskalia. It opens with one of the best electronic music tracks, not only by Krzysztof, but in general, with an extremely characteristic leitmotif, under which there is also a very low and dense bass.

    The Japanese amplifier showed this recording in this way, i.e. it emphasized the midrange and saturation. So it sounded incredibly coherent, dense and strong. It was a real spectacle with proper momentum, with powerful imaging and large-scale sound sources. The most important in this sound is the midrange and it sets the perception. Not because the top and bottom are not there, but because the midrange is so emotionally engaging.

    To find out what the treble is about, I reached for two albums, which I often listen to, to quickly find out what and how: Pyramid by The Modern Jazz Quartet, a 1960 album, and Art Pepper Meets The Rhythm Section, a fantastic album recorded by Roy DuNann in 1957. They both sound great because they are tonally balanced, but also very dynamic. Both of them also have preserved natural colors (I listened to them from 20-bit K2 remasters).

    Although the electronic music from which I started listening may seem not the best choice to assess the timbre, harmonics, coherence, etc. of the sound, it really suits it perfectly, you only need to know it from many other auditions, know the sound of one or another instrument and "signature" of one or another musician. So I wasn't surprised that both jazz albums showed the same as Dudaskalia before, i.e. incredible sound saturation and its beautiful coherence.

    There was a strong, dense treble. Just in such a combination. High tones are slightly smoothed by this amplifier, but are not withdrawn. They have a sweet overtones, but also show weight and impact, so they do not hide behind the midrange. On the one hand, they are complementary to the midrange, but on the other, they are a complement that is an integral part of the basic range. The cymbals had a sonorous character, their differentiation was also heard, it was not played on one note.

    The A-2 SE is a powerful, current-efficient amplifier. It easily controlled the Harbeth M40.1, which I use every day. But it did it its own way. Already on Krzysztof Duda's album, and then listening to double basses on MJQ and Art Pepper albums, I heard that it is slightly tuned up. This was confirmed by listening to the Companion SACD version, in particular in the Use Me track.

    It turns out that the amplifier emphasizes the upper bass and the lower midrange. This gives a lower than usual sound, although open from the top, but also lowers the sound of instruments operating in this range, male voices, and even women's if they are as low as the Barber’s. It does not bother, but with discs on which there is a lot of bass, the amplifier's own character will be shown more strongly.

    In turn, with discs that usually sound too light, due to poor production, and because they are intended for listening in the car - let it be the Red Pill Blues cooked by Maroon 5, the amplifier will handle them perfectly, because it will saturate, complement, "straighten" - to some extent - producers' choices. We will get a strong kick drum with it, momentum, large space and smooth vocals - yes, no underlined sibilants, although there will be a lot of treble.

    So - it's beautifully sounding amplifier. Not for everyone, because it does not offer a crystal open treble and is not clearly dynamic, which is why the selectivity is only OK. It didn't matter much to me because I like such sound. But not everyone must like what I do, right? One thing you need to know and consider, regardless of your preferences, is that the selected solutions affect the way the bass sounds like. It is full-bodied, there is a lot of it, but there is no clear attack and it is not as well-controlled as, say, by Hegel amplifiers.


    A-2 SE SoulNote is an amplifier that has all the features for which we love good audio components. It is warm, rich and saturated. It shows a large space, although without precise location of phantom images. The bass is strong and dense, but it is not always perfectly kept in check, so it is better to combine the speakers with the tested amplifier, which are slightly contoured, which means the mid bass attack is emphasized.

    Ultimately, it is a beautiful, "golden" sound that never tires, on the contrary - encourages you to buy more albums. The more that the device is resolving and differentiating, which will allow us to enjoy best releases and good realizations too. For all this – the RED Fingerprint - our first in 2020!

    Mechanics | The A-2 SE is a beautiful amplifier - both outside and inside. Its mechanical structure is a combination of various materials in a thoughtful way. The whole is bolted to a steel base - electronics and heat sinks separately, power supply transformer separately. Aluminum elements forming the sides and top are screwed to the base. The sides and front are ribbed, which looks great, but also stiffens the whole structure.

    The top is double. First there is a steel plate, shielding the interior, which is not bolted to the housing, and from the outside there is an aluminum frame that mechanically stabilizes the housing; it is screwed on at three points. The feet are also placed in three places - they are small spikes. Two are bolted in the rear corners, and one in the front, in the middle, but not to the base, but to the plate on which the power transformer sits. It is shielded and stands on a separate platform that is attached to the bottom. A spike then holds the transformer first, and only then the housing.

    Electronics | The amplifier consists of three sections: input circuits, output stage and a power supply. There is a separate PCB with a microprocessor controlling the attenuator and protective circuits.

    Preamplifier | In the input there is a PCB with only an input selector and an attenuator, together with an advanced stabilized power supply - it features a separate secondary winding from the transformer. The input is selected in relays, same ones are also used for the attenuator. This is a discrete balanced system with SMD (large) resistors. Buffers, DC Offset and mirror sources have been eliminated from the signal path. Instead, separate transistors and orange LEDs are used, which can be seen from under the upper wall. As we read in the company materials, this allowed to shorten the signal path and simplify the layout.

    There is a large number of high-class polypropylene capacitors. The company says that when the amplifier works as a power amplifier, for example with an external preamplifier or in a home theater system, the input circuits are completely disconnected from the power supply, the microprocessor that controls them is also turned off. This reduces noise. Let's add that the plates are made of thicker than usual copper (70 μm).

    Output Stage | From here, the signal runs to the PCBs placed at sides, that are output stages. It's a discrete transistor system. The output stage uses a Darlington circuit, with four small and fast input transistors that have been shielded, and another four (per channel) bipolar transistors, working in class AB, in push-pull mode (Sanken, 2SC2837 + 2SA1186). The transistors are screwed to a thick aluminum bar, and then to the heat sinks. They are shaped like a chimney, which is supposed to help - as the company says - in cooling. The amplifier works without feedback and is a completely balanced design from input to output.

    Power Supply | The power supply is based on a large, 600-watt toroidal transformer. A bank of several dozen small capacitors suppressing power grid ripple (voltage smoothing) works with them. The idea is for the capacitors to overcharge as soon as possible and thus react faster to power surges.

    Connectors | The device is pleasant to use because the knobs are comfortable and the volume readout is clear. The connection sockets are gold plated, as are the speaker terminals. Interestingly, all sockets, just like the chassis, have something to do with Luxman devices, as if the same subcontractors worked for both companies. This is a great design and equally good workmanship.

    Technical specifications (according to manufacturer)

    2 x 100 W (8 Ω) | 2 x 200 W (4 Ω)
    1 x 400 W/8 Ω (in bridge mode)
    THD: 0.03% (50 W, 8 kHz)
    Frequency range: 3 Hz-240 kHz (+/-1 dB)
    Input sensitivity / impedance:
    XLR: 700 mV/16 kΩ | RCA: 700 mV/8 kΩ
    S/N: 110 dB
    Power consumption: 355 W | 125 W (idle)
    Dimensions: (W x D x H) 455 x 162 x 423 mm
    Weight: 20.5 kg


    Reference system 2018

    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