⌈ Established in 2009, Foshan ShuangMuSanLin Electronics (S.M.S.L) is a manufacturer based in the industrial part of China, Schenzen Province. It offers nicely made products aimed at the audiophile part of the society, such as: D/A converters, headphone amplifiers and power amplifiers. We test its AO200 integrated amplifier. ⌋

O LESS THAN SEVENTEEN MODELS of integrated amplifiers and power amplifiers can be found on the website of the Chinese company SMSL, both with its logo and the logo of the VMV sub-brand (SMSL is an abbreviation of the manufacturer's name: Foschan ShuangMuSanL in Technology, hence no dot after the last 'L'; later in the test I will use the simplified version - SMSL). Some of them seem almost identical, for example the DA-9 and the tested DA-200, others differ in functionality or finish.

However, they are connected by the use of ready-made power amplifier modules, working in class D, and also by an absurdly low price. The tested integrated amplifier costs only EUR 279, which at today's low Polish zloty exchange rate translates into PLN 1,280.35 (as of 08/11/2021).

Until recently, it would only be possible thanks to the use of native Chinese components in the design, combined with low labor costs and the scale effect. In the case of the tested amplifier, this first component is only partially true, because the housing is actually made in China, just like the printed circuit boards, but the key components were bought abroad - in Japan, and in Germany .

▌ AO200

The AO200 IS AN INTEGRATED AMPLIFIER with an integrated Bluetooth receiver module. The company materials and the inscription on the packaging inform about it, and call it a "Bluetooth digital amplifier", and also "High Resolution Power Amplifier", which are not true names for it.

Neither is it a "digital amplifier", because the module of the German company Infineon Technologies used in it is not digital, but analog (although it works in class D), nor is the amplifier "high definition", because the digital link, the aforementioned Bluetooth, is not an HD link, and an ordinary SBC/AAC, working with compressed 16/44.1 signal. In addition, it is not a 'power amplifier', but an 'integrated amplifier'. However, this type of marketing language is used by the entire audio industry, not only for the manufacturer in question.

To the point - the AO200 is a small device, measuring 210 x 40 x 170 mm (width x height x depth), weighing less than a kilogram. The amplifier is made with attention to detail and it just looks very good. The only problem I see is the incorrectly spelled 'Bluetooth' name that appears on the display. The aluminum housing is anodized black, and on the front there is a small, color liquid crystal display. In the middle there is a volume knob, integrated with the switch that takes us to the menu, which I’ll discuss in a moment.

⸜ FEATURES The amplifier offers two analog inputs, unbalanced RCA and balanced XLR, stereo RCA output for a subwoofer, and the already mentioned Bluetooth wireless connectivity module. However, there is no digital input, unless we mention the USB (flat) input, which is located on the rear panel. However, it only transmits mp3 signal, so don't focus on it.

The signal to the speakers is sent through two pairs of tiny, though gold-plated, speaker sockets, for which it is best to use banana plugs (or BFA). Importantly, the AO200 has an internal really good power supply, so it doesn't need an external wall power supply like many other products of this type.

Though small, with only three inputs, the AO200 has quite high functionality thanks to its microprocessor control. In its menu, we can choose one of eight tone control settings, boosting the bass or treble, or both. This will come in handy if we use small loudspeakers or if we want to "tune" the sound in our own way. One of the most interesting settings is called SDB and it is a proprietary development of the SMSL (SMSL DYNAMIC BASS). It is based on the classic loudness system, which uses the Fletcher-Munsen curves, but in a version that adjusts the correction to the volume level. You can also turn off these compensations and stay in the "Direct" mode, which I did.

The menu also allows you to change the brightness of the LCD display, select the input, and activate the amplifier's overload protection system. It affects the sound, so it is worth using it if we do not listen to music too carefully, for example during a party. This circuit is part of the power amplifier modules and thanks to it it will be difficult to damage the amplifier.

⸜ TECHNICAL SOLUTIONS All three sections of the integrated amplifier, i.e. the preamplifier, the attenuator and the power amplifier, are really very good in the tested device, although quite simple. The preamplifier section has a fully balanced path, so during the test the signal was sent to it via XLR cables. Moreover, the entire path of the AO200 is balanced as both the attenuator and the power amplifier modules operate with a balanced signal.

And the attenuator is the NJW1194 integrated circuit from the Japanese company New Japan Radio (NJR). This circuit is integrated with the input selector. The signal prepared in this way goes to the most important part of the device, i.e. the power amplifiers. As I mentioned, these are analog D class modules, prepared by Infineon Technologies. They operate based on the MERUS technology patented by this company, which allows to amplify the signal not in two, but three stages, thus minimizing heat loss.

The system is therefore extremely efficient and does not require cooling. In the AO200, just in case, small aluminum elements are screwed to the bottom of the PCB, which are pressed against the housing with a paste between these elements, acting as a heat sink. These circuits offer an output of 30 W, but at peak it can increase up to 80 W (into 8 Ω). Although the manufacturer lists the maximum output with as much as 10% distortion, it should be assumed that even with the usual 1% distortion output should be significant. There is no need to use filters at the amplifier output, which results in a simpler audio path.

Let me add that in the audio path we find relatively expensive components, such as capacitors from the German company ERO, MELF (Metal Electrode Leadless Face) resistors, one of the best ones when it comes to surface mounting, and this is what we deal with here. There are nice OP1678 integrated circuits in the preamplifier section. And there is also a power supply. It is a system "boosted up" by SMSL, a switching power supply with a power of up to 300 W (!) With an input filter and a low leakage transformer.

⸜ REMOTE Despite its low price, the amplifier comes with a nice, quite functional (universal) remote control. To control the AO200, you have to press the 'A' button, and then you can change the volume, inputs, navigate through the menu or activate the mute mode.

Summarizing this part, let's say that for little money we get a small but well-designed and very well-made amplifier with high output power.

▌ SOUND

⸤ HOW WE LISTENED The S.M.S.L AO200 amplifier was tested in the "High Fidelity" reference system. In this case, I used the Mytek Brooklyn Bridge audio file player and a balanced link with the Acoustic Revive Triple-C cable as the main one. The device stood on its own rubber feet, on the top shelf of the Finite Elemente Master Reference Pagode Edition rack, and was powered by the Harmonix X-DC350M2R Improved-Version cable. The signal was sent to the speakers via the Western Electric NOS cable.

Recordings used for the test | a selection

⸜ CHARLIE HADEN, PAT METHENY, Beyond The Missouri Sky, Verve Records 537 130-2/Tidal, FLAC MQA 16/44,1 (1997).
⸜ DAVE HOLLAND, KEVIN EUBANKS, OBED CALVAIRE, Another Land, Edition Records EDN1172/Tidal, FLAC MQA Studio 24/96 (2021);
⸜ MIRACLE OF SOUND, Level 11, Tidal, FLAC MQA Studio 16/44,1 (2020).
⸜ CAMILA MEZA & THE NECTAR ORCHESTRA, Ambar, Masterworks (3) 19075877572/Tidal, FLAC MQA Studio 24/96 (2019).
⸜ DEAD CAN DANCE, Dionysus, [PIAS] Recordings PIASR440CDX/Tidal, FLAC 16/44,1 (2018).
⸜ JONI MITCHELL, Bue, Reprise Records MS 2038/Tidal, FLAC MQA Studio 24/192 (1971/?).
⸜ KINGDM (feat. Soran & Reo Cragun), Your Love, Capitol Records/Tidal, FLAC MQA 24/44,1, SP (2018).
⸜ VOICES8, Winter, Decca 4830968/Tidal, FLAC 16/44,1 (2016).

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SO SMALL IN SIZE AND OFFERING SUCH A BIG SOUND, that’s what I would like to write right now, at the beginning of the test. Moreover, I wrote this because it's one of the first thoughts that comes to mind when you turn on the music and turn up the volume knob. Modern technology is kind to this type of product, because the tiny enclosure houses the amplifier that easily drove the large, power-hungry Harbeth M40.1 loudspeakers featuring large 30 cm woofers. Many "full-size" amps struggle with this task, and the AO200 had no problem with that.

You have to put it in the right context, that's clear - the 6-watt SET amplifier with a 300B tube connected to the same speakers struggles at higher volume levels, and yet it still plays in a completely different league, maybe even on a different planet. Even so, we're still in the same universe where density, fullness, and saturation matter.

Because these are the elements the AO200 charms listeners with. It sounds, to be honest, like a warm tube amplifier. PAT METHENY with CHARLIE HADEN from the Beyond The Missouri Sky album sounded extremely warm and low, just as the DEAD CAN DANCE duo's Dionysus played right after that. I do not know to what extent it is a feature of the design as such, and to what extent it is the proprietary features of the amplifier modules that S.M.S.L buys from a German manufacturer, but this is how I heard it. By the way, that’s something new - a Chinese company builds a device around foreign components - as you can see, the world is changing, including the audio world.

But to the point - the sound, as we have already established, is big, dense and saturated. The jazz recordings and small classical compositions sounded beautiful with the AO200 amplifier. But the aforementioned Dead Can Dance, based on powerful layers, also sounded great. The point is that the tested amplifier never allows for sharpness, does not brighten the sound, and therefore is very forgiving.

It is not particularly clear, meaning selective sound, and the resolution is just good. The amplifier plays with big plans and with dense music it sometimes loses composure. It is worth turning down the volume in such situations, and then everything will "fall back" into place. It was the same not only with the aforementioned albums, but also with the recordings of the French group GRAND BLANC from the Mémoires vives album. It is important, because that is quite brightly, hardly recorded music, as befits representatives of the new wave of music once called cold wave.

However, getting back to the beginning, recordings in which time is important, including longer phrases sound most beautiful with the tested amplifier. Vocal recordings with it are simply great. Considering the price point, you can even say that it is performance is sensational. The voices are big, quite well focused in front of us, have a nice timbre and sound surprisingly natural, like CAMILA MEZA from the Ambar, JONI MITCHELL from the classic Blue, or the single Your Love (highly recommended!) by an artist hidden under the KINGDM acronym. Interestingly, although the AO200 makes the recordings similar in terms of dynamics and timbre, the differences between the latter recordings were perfectly legible.

Like I said, the amplifier drove the Harbeths great, which means that it will sound equally well with small stand mount speakers, usually of low efficiency. And only with recordings where the bass reaches very low frequencies and there is a lot of it, as on the mentioned KINGDM album, you could hear a slight distortion at the very bottom of the band. The bass is surprisingly low and strong with this amplifier, but it is not controlled in the same way as with classic designs. It has a soft character and it is more about the timbre and a good connection with the midrange, rather than about ultimate control over it.

Nevertheless, the device is really beautiful, for the money one would have to say: ultra-beautiful, it plays well-recorded music and can reproduce both its timbres and momentum - this was the case, for example, with the Winter album by the Voices8 vocal group.

⸜ BLUETOOTH Everything that I wrote concerns music played from a file player via the XLR input. This is the best input of this device and I would use it when listening to music. The AO200, however, is an amplifier with greater potential, because it will suit the needs of people who spend most of their time doing something else, in the background listening to music from their smartphones.

The good news for them is that they will benefit from much of what I wrote about the AO200 above. Admittedly, much of the information will disappear, the sound will be dynamically flat and more subdued, yet it will still be warm and - ultimately - pleasant. The tonal center of gravity will be placed higher than before, the treble will be more strongly emphasized, and yet there will be no doubt that this is the same amplifier, that the music it plays has the same DNA as with the signal sent through the XLR inputs.

▌ SUMMARY

The AO200 from S.M.S.L is a surprisingly good, really nice-sounding amplifier that offers a sound similar to that of a tube amplifier. Considering its size and price, it is downright indecently good sound. And this one is warm, has a low tonal center of gravity and offers a low, dense bass. The high treble is withdrawn and warm, so it never hurts. The amplifier copes well with difficult loads and will drive any loudspeakers. Let's add a very solid workmanship and we have another product from China that no company from another country will be able to offer at such a price. ■

Technical specifications (according to the manufacturer)

Nominal output:
150 W/2Ω | 90 W/4 Ω | 40 W/8 Ω
THD+N: 0.003%
SNR: 110 dB
Channel separation: 98 dB
Input sensitivity/impedance: 280 mV/47 kΩ
Average power consumption: 40 W
Power consumption in standby: 0.5 W
Dimensions: 210 x 40 x170 mm (W x H x D)
Weight: 0.96 kg