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An economic amp with a major power-up

The SMSL SH-9 arrives almost exactly two years after the release of its predecessor, the SH-8. The SH-8 impressed reviewers by being a solidly performing balanced amp for under $200. It was a great choice for the budget-conscious audio lover looking to jump into balanced sound. 

The SH-9 is a classic upgrade: it does everything its predecessor did, only better. The amp is both more powerful and more discreet. The screen is larger. The protruding volume knob is easier to operate. And to top it all off, the SH-9 matches the SU-9 and SU-9n DACs in size and aesthetics for easy stackability.

Power you can feel

Entry-level and mid-tier amps all beg the same question. Are they powerful enough to drive all my headphones? The answer in this case is (almost) definitely. With 6W at 16Ω and 3W at 32Ω, the SH-9 can power nearly everything. And if you need a little extra oomph, just toggle the gain switch for another 10 decibels. 

(If you’re unsure about your headphone’s power requirements, check out this handy headphone power calculator, courtesy of DigiZoid.)

The THX AAA-888 offers extreme clarity

The THX AAA lineup of amps are known for their power and clarity. Unlike many amplifiers, THX AAA amps use a feed-forward error correction topology that removes common distortion issues. To put it simply, the amp measures errors in an early part of the system and corrects them in a later part of the system. 

The THX AAA-888 is the most sophisticated iteration of the lineup. Its distortion levels are seriously low. Signal-to-noise ratio is 137dB, meaning that you’d have to crank the amp up to 138dB before hearing any hiss. And unless you’re trying to permanently damage your eardrums, you’re probably not going to do that. 

Desktop friendly

Despite its massive output capabilities, the SH-9 is actually quite small. At 7.3” on its longest size, you should have no problem fitting it onto most desktops. And as we said, it’s designed to stack with the SU-9. The stacked pair are a modest three inches in height. 

Product highlights

• THXAAA-888 Headphone Amp with THX AAA Technology
• 6W into 16Ω, 3W into 32Ω
• Frequency response: 0.1-500,000Hz
• SNR >137dB
• THD <0.00006%
• Ultra-compact design that’s perfect for desktops
• Balanced stereo headphone output
• Balanced stereo line input
• HIgh precision resistors for temperature stability
• Pop-less design with high-quality relays
• 256-level relay volume control
• Switchable gain control
• 1.9” LCD display
• Remote control
• Inputs: 1 balanced, 1 unbalanced
• Outputs: 1 balanced, 1 unbalanced
• Output power
• 6W x 2 (16Ω)
• 3W x 2 (32Ω)
• 440mW x 2 (300Ω)
• 220mW x 2 (600Ω)
• Output noise: 1.9uV, A-weighted
• THD+N
• -123dB, 0.00006% (A-weighted)
• -117dB, 0.00013% (20-20kHz, 32Ω, -3dB)
• -125,dB 0.00006% (1kHz, 16Ω, -3dB)
• Input impedance: 47kΩ
• Output impedance: Near 0Ω
• Gain: Low (+0dB), High (+10dB)
• Power supply voltage/frequency: AC100-240V, 50-60Hz
• Power consumption(EN60065): 24W
• Power consumption in standby mode: <0.1W
• Size: 7.38 x 6 x 1.5” (187.5 x 154 x 40mm)
• Packing size: 11.1 x 9.1 x 3.1” (282 x 232 x 79mm)
• Weight: 1.7lbs (790g)

What’s included

• SMSL SH-9 THX AAA-888 Balanced Headphone Amp
• Remote Control

What pairs well 

• SMSL SU-9 Balanced MQA-Enabled DAC
• SMSL SU-9n Balanced DAC

Featured reviews

"A detail monster." -SoundNews

"Instant banger!" -Joshua Valour

"I'm giving this a big thumbs up." -Z Reviews

""If you're looking for a full-time desktop unit with the THX stamp of approval and balance funcionality, I think this one fits the bill quite nicely." -Home Studio Basics