SMSL SU-6 & SH-6 Review

On this page, we’re checking out the SMSL SH-6 Desktop Amplifier.

SMSL SH-6 Compact Desktop Amplifier

The SMSL SH-6’s dedicated web page can be found here. It costs $119 USD from Shenzhen Audio. 

The SH-6 is a budget-friendly, high-performance, low distortion precision linear feedback (PLFC) amplifier. It offers 2 stages of gain, an impressive THD value, low-noise PSU, and plenty of power to drive the majority of the cans on the market. It can deliver 2.6W into a 16-ohm load. Additionally, it features a pop-less design and a compact form/factor.

Here are the highlights of the SMSL SH-6 Desktop AMP.

• Low-Distortion Precision Feedback Circuitry
• Low-Noise Power Supply
• HQ Relays & Pop-Free Design
• 2-Step Gain| L:0dB H:15.5dB
• PRE – HPA Mode Switch
• RCA IN & RCA Outputs | 6.3mm UNBAL HP Output

Packaging & Accessories

The SMSL SH-6 amplifier comes in a small-sized, white rectangular box just like its companion, the SU-6. The box design is the same as the SU-6. The packaging is not as plain as other units from SMSL. The top side of the package has the device outline image and it looks quite nice. The SMSL is still after simplicity and there are no specifications or any product info listed anywhere on the box. Although the tiny sticker with the model name and barcode on the side is still present. Opening the box grants you access to the foam compartment that protects the device from damage during transportation. The unit is neatly packed as usual. 

Moving on to the accessories, SMSL provides a couple of manuals and warranty sheets and a C7 power cord with exterior ground wire. There is nothing else in the package, no 6.3mm adapter or remote either. It is a simple, plug-n-play amplifier without fancy features.

Design & Build Quality

Measuring 14 x 2.8 x 10.5 (WxHxD) centimeters, the SH-6 amp shares pretty much the same form and factor as the SU-6. It is naturally the perfect companion to the SU-6 DAC. As a combo, they can be stacked therefore they have a very small footprint and they won’t take much space on your desk. The SH-6 is a powerful amp, despite its compact form and factor. It features a simple design with switches and a volume pot on the front. The device has an aluminum chassis and SMSL offers it in 2 different colors. It is available in black, and, silver. The review unit they sent me is in black and the metallic finish looks great up close. Additionally, the volume pot is different than what we have seen on other SMSL devices. I can’t see any assembly issues or imperfections so the build quality is brilliant as usual with SMSL products.

Moving on to the device layout, we see a new, color-matched volume pot, two lever style switches, and a single-ended 6.35mm headphone out. The far-left switch acts as a power switch and amp mode selector at the same time. You can seamlessly switch between HPA and PRE modes. The switch on the right is for the gain. The layout is simple and quite easy to use. You won’t be needing the user manual for this unit.

The rear side is where all the I/O options are located. From left to right, we see RCA inputs, RCA preamp outputs, a ground terminal, the IEC C7 AC power input, and, a power switch. Additionally, there are 4 rubber feet under both of the devices, helping them to stay put on the desk and resist cable drag.

Similar to the SU-6, the SH-6’s build quality is impressive and it is built to last. The aluminum chassis feels rigid as well as all the sockets. The knob feels durable as well but a smaller, more elegant one could’ve also been great, aesthetically speaking. If you like to use ultra-short cables between your dacs and amps like me, you should know that both RCA and TRS sockets align so you can use ultra-short RCAs with this stack. Kudos to SMSL for keeping up the build quality game. Well done.

Technology & Power

The SH-6 boasts a lot of power for its size and it can dish out 2.6W into a 16Ω load and 1.3W into a 32Ω load. It utilizes ultra-low distortion precision feedback circuitry and offers a 0.00006% THD value according to SMSL. This is a wild number that was nearly impossible in mere three years ago with this form and factor. The unit has two gain options. Low gain is essentially zero, (0dB) and high gain offers a nice boost of +15.5dB. This means that SH-6 can successfully feed the majority of the headphones on the market right now.

Additionally, not only the THD but also the SNR and DNR values are impressive as well. On paper, this may be the best amplifier in this price bracket. More on that later!

Controls & Ease of Use

The SH-6 has a simple, easy-to-use design. It has lever-style switches, it has a white LED to let you know that it is working, it has a knob to control the volume and that’s pretty much it. Connect your RCAs, plug in the power cable, unscrew the ground terminal, connect the exterior ground cable, make sure it’s clamped, turn the device on, choose your poison, whether it’s a sensitive IEM or an inefficient full-size headphone, and you’re good to go. Easy. Practical. Fast. No fancy features, no filters, nothing. Just pure, plug-n-play, audio bliss. 

AMP Performance

SMSL’s SH-6 follows its bigger brother SH-8s’ footsteps with its PLFC amplifier circuitry and offers the same benefits in a smaller, more compact chassis. Similarly, it features a very low noise floor, high power output, and low distortion. We have already reviewed the SH-8s and awarded the unit with an HFN recommendation. As far as I understand, SMSL somehow managed to take everything great about the SH-8s and squeezed them into the compact chassis of the SH-6, except for the balanced output & BAL-related components. Anyhow, without further ado, let’s go into the details of the sound.

Starting with the background, the SH-6 does not make you long for the SH-8s when it comes to the noise floor & hiss. The amp is dead silent, even with sensitive IEMs. The SH-6s is a clean-sounding amp with no saturation, just like its companion, the SU-6. It offers surprisingly good performance despite its entry-level price tag. I can easily say that you’ll have trouble finding a worthy rival for the SH-6, around the same price mark. The unit offers a clean, resolving, and linear response with plenty of details. It also scales well with higher-priced DACs with good single-ended implementation, such as the Topping E50. 

Moreover, just like every well-implemented amplifier in our industry, it does exactly what it should. It amplifies; without saturating, distorting, or manipulating the sound signature of your source. The SH-6 showed excellent tonal balance with every pairing that I tried during my time with it. It sounds neutral, clean, and linear to my ears and these are serious complements for a unit that costs a little over a hundred bucks. The sound is far from ”boring”, it does an excellent job of conveying every detail of a well-mastered track to you, to your earphones or headphones. I can say that the SH-6 could easily be placed side by side with a DAC that cost double maybe triple its price tag, just like the SU-6. That’s why they are perfect together. I’ll go into more detail about the pair on the next page.

I wanted to see how it fares against one of the bests of industry. A head-on battle with the JDS’ Atom+ Amp sounded fantastic to my ears so I battled them from one genre to another. The Atom series has long carried the flag of the best sub-$100 amp, but now they are in trouble, to say the least. The SH-6 sounds slightly more resolving with more accentuated details compared to the Atom+ Amp. The Atom+ is naturally the most formidable rival of the SH-6 thanks to JDS’ excellent track record when it comes to DACs & AMPs. The Atom+ amp takes the imaging a step ahead, providing a tad more compact soundstage that feels slightly more accurate. The margin between them is quite small, and both of them are excellent amplifiers that won’t let you down in any way. More on this on the next page.

The review continues on Page Three, after the click HERE or by using the jump below.

Page 1: SMSL SU-6 Desktop DAC, Packaging & Accessories, Design & Build Quality, Controls & UI, Bluetooth Capability, DAC Performance

Page 3: SMSL SU-6 & SH-6 DAC & AMP Stack Performance, Comparisons, Pairings, Last Words