SMSL SH-9 review

(Disclaimer: sample of SMSL SH-9 provided by can buy SMSL SH-9 on Aliexpress store: HIFI college store)

The SMSL SH-9 is the latest THX based amplifier and this price today is just $289.99. But this time SMSL amplifier comes with a remote control and display. And being THX based it measures excellently. SMSL SH-9 measurements are really nice, but what exactly did SMSL achieve in sound quality in its new model, and what are kind of product turned out in general, we will try to understand below.


The main difference between the new SH-9 and the previous SP200 model is the display and remote control. We’re delighted that SMSL has put a small LCD screen here and ditched all three of those switches, it now looks much cleaner and more elegant than ever.

This colorful LCD screen and the included remote control are what you have to pay an extra $25 for, which is a difference from the previous SP200 model, which actually has the same sound quality, but we will return to this a little bit later.

The SMSL SH-9 looks like a matte black metal brick with two panels attached at the top and bottom. Its body is about 3.5mm thick, so wireless interference shouldn’t be a problem. On the front is an LCD screen, volume control knob-a huge upgrade compared to the one on the SP200. This is a stepped volume knob with exactly 99 steps.

The volume knob uses a ladder of high-performance analog relays to control the volume. This is a high-end step attenuator with relay control, such as many premium companies use in their top-level amplifiers, and this is really pleasing in the new SH-9.

Under the block there are 3 rubber feet, which can sometimes cause the unit to tilt if you want to put something on top of the device. However, you can separately buy a few extra rubber feet and put two in the corners so that it does not wobble on your table. Otherwise, we think the build quality and design is really good and beautiful.

All disassembly screws are located under the device to make the SH-9 look much cleaner. Under the device we can find the 7-pin connector, exactly the same as on their SU-9 DAC, it is intended for flashing the device. Everything else looks very nice, looks clean and minimalistic.

SMSL only offers it in matte black, and at just 790 grams, it looks pretty compact. We can say that the size is slightly smaller than other mid-range headphone amplifiers, it can be easily placed in almost any stack, it is really versatile.

Controls, I/O, menu

On the front of the SMSL SH-9 we can find a volume knob that acts as a menu navigator and select button, an LCD screen and two headphone outputs: XLR and 6.35mm (1/4″). The screen have medium size for similar devices is 1.9 inches, but thanks to the larger letters, you can clearly see the volume level, selected input and gain position.

On the rear panel you can see two analog inputs, XLR and RCA, as well as a universal input from 100V to 240V AC.

4 pin XLR output on front is usually associated with balanced headphone output, but actually the circuit inside the SH-9 like the previous SP200 amp is actually not balanced. It does have balanced inputs though on the back these dual three pin XLR inputs, but they are converted to regular single ended inputs, so you may as well just use the RCA inputs though you do have that flexibility and with just a power socket on the back, that’s all it does is act as a headphone amp, so no pre-amplifier options here.

The SMSL SH-9 deliver up to 6 watts of power at 16 ohms or 3 watts at 32 ohms on both the 6.35mm (1/4″) and 4-pin XLR outputs, it doesn’t really matter if you have a balanced headphone cable or not (because, as we wrote above, this is not exactly a balanced output), as it will deliver full power to both headphone jacks. Given this power, the SH-9 will give even the most demanding headphones warm-up, such as high impedance dynamic drivers or planar magnetic drivers.

The SMSL SH-9 uses the same 24-watt ultra-low power supply as the SP200. As with all THX AAA designs, the electrolytic caps are not located in the signal path, but are used for filtering and storing energy.

All functions can be controlled with the remote control or with the volume control knob, which simultaneously serves as a joystick for its menu. In standby mode, one tap on the handle will turn it on, and another tap will enter its menu, where you can select:

  • Input – Balanced (XLR) or Unbalanced (RCA)
  • Gain: Low (0 dB – best setting for IEMs or sensitive headphones) or High (+10 dB – for tight full-size headphones)
  • Volume Mode: Enable or Disable. When its enabled, it will reduce the frequency of relay operation, thus increasing the service life of those relays. If you disable this feature, you will hear clicks on every volume step.
  • Brightness
  • Version – Hardware and Software version


THX (a company founded by George Lucas in 1983) was mega-famous in the field of full-length home movies – but in recent years, the popularity of certification for domestic use has waned. The firm has taken a number of steps in various directions – and THX AAA is one of them. According to the company, we are facing a real revolution – intermodulation distortion is reduced by a hundred times, harmonic and transient distortion – by twenty times. The result is a hyper-realistic sound effect. As well as reducing energy consumption by a factor of ten, which is critical for portable devices and their batteries.

THX AAA is not the same as the THX certification previously available. All this splendor is now achieved through the proprietary development of THX (patent pending), which lowers the bias current and reduces distortion. The heart of the new technology is the THX AAA – achromatic audio amplifier, an integrated solution placed on a single chip, which provides incredible playback time from a single 3.6V battery and “the best in the world” in terms of distortion.

And now THX AAA 888 technology delivers the highest fidelity with exceptional power output and ultra-low crosstalk.


Pure amplifiers in general should have sufficient transparency and neutrality. Their task is to amplify the signal, not to add and change it in any taste feed. But this is, of course, on paper and measurements. In fact, the situation is somewhat different, although the amplifier from SMSL is quite close to the ideal. It is almost transparent and its impact on the record is quite modest. And yet, it is there. Thus, it turns out that the device should be described just in the plane of the signal difference before and after amplification.

Low Frequency carry the most differences. They are enough to accurately maintain depth and speed, but they literally add a little massiveness and corporeality. The sound gains a little more confidence and emotionality. The recording begins to sound a little more warm and enthusiastic. In our opinion, low frequencies are a strong point of the SH-9. Here they are very elastic and full-bodied, almost in any records the bass is always in its place, never interrupting the middle range. They always sound very accurate and clear.

The midrange does not differ much. SMSL SH-9 keeps the recording as it is. At the same time, it adds a little warmth and weight on the one hand, but perfectly emphasizes the transfer of nuances of sound, timbres and emotions on the other.

High Frequency is practically no different. Just as detailed, transparent and expressive, without smoothing or simplifying. Without sagging dynamic range, but just as fast, detailed and long where it should be.

The scene is also fully inherited from the source. The amplifier does not change its structure, only slightly increasing its width and depth. Thanks to this, the positioning of instruments, the separation of plans and the transmission of the overall sound picture are slightly improved.

Note that we tested the SH-9 with its sibling, the new SMSL SU-9 DAC, which perfectly combines aesthetically complementing the stack with its repeating design and sound delivery.


The SMSL SH-9 is equipped with the most high-performance THX-AAA-888 modules, one of the best relay-controlled volume, providing enough power for even the most demanding headphones. Due to its noiseless background, it worked equally well with both ultra-sensitive IEMs and rigid planar magnets. Display and remote control are a good addition for $25 difference from the previous model, and apparently the company will have to remove the SP200 from sale as the new SH-9 does not leave it a chance.

This really deserves our highest rating, and we are adding the SMSL SH-9 to the “Our Choice” section. If you like undistorted and unpainted feed, and do not want to worry about the power reserve at an affordable price SMSL SH-9 will be the best choice in this price range for today.

“Our Choice”

Buy SMSL SH-9 on
Aliexpress store: HIFI college store)

SMSL SH-9 Specifications

Inputs: Balanced x1, Unbalanced x1
Outputs: Balanced x1, Unbalanced x1
Output Power: 6W x 2(16Ω), 3W x 2(32Ω), 440mW x 2 (300Ω), 220mW x 2 (600Ω)
THD+N: -123dB, 0.00006% (A-Weighted)
Input Impedance: 47kΩ
Output Impedance: Near 0Ω
Power supply voltage/frequency: AC100-240V, 50-60 Hz
Power consumption(EN60065): 24W
Power consumption in standby mode: <0.1W
Size: 187.5x154x40(mm)
Packing size: 282x232x79(mm)
Weight: 790g

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