The SMSL SP400 arrives just over a year after the release of its predecessor, the SP200. The SP200 wowed reviewers with its “vanishingly low distortion and tons of power.” The SP400 retains the THX AAA-888 amplifier of its predecessor and, with it, most of its predecessor’s specs. So how’s it different?
You’ll find most of the upgrades on the box itself. The SP400 has been given a nice bright 1.9” LCD display, a full-function remote, and a pre-balanced output. Plus, it matches the SM400 DAC in size and style, so you’ll be able to stack the two with ease.
Power for all your headphones
Is it powerful enough to drive all your headphones? The answer in this case is (almost) definitely. With 12W at 16Ω and 6W at 32Ω, the SP400 can power nearly everything. And if you need a little extra oomph, just toggle the three-position gain for an extra three to six decibels.
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.
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The THX AAA-888 is the most sophisticated iteration of the lineup. Its distortion levels are seriously low. Signal-to-noise ratio is 133dB, meaning that you’d have to crank the amp up to 134dB 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 SP400 is actually quite small. At 8.6” 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 M400. Together, the pair reach just over three inches in height.
Product highlights
THXAAA-888 Headphone Amplifier with THX AAA Technology
Ultra-compact design
Balanced stereo headphone output
Pre-amplifier application
Balanced stereo line input
High precision resistors for temperature stability
Pop-less design with high-quality relays
High precision and low noise 256-level relay volume control
3-position switchable gain control
DC, over-voltage, over-current, short-circuit and thermal protection
High-efficiency ultra-low-noise power supply
Full function remote
1.9” LCD display
Specs
Inputs: 1 balanced, 1 unbalanced
Outputs: 1 balanced, 1 unbalanced, 1 pre-balanced
Output power
Balanced
12W x 2 (16Ω)
6W x 2 (32Ω)
880mW x 2 (300Ω)
440mW x 2 (600Ω)
Unbalanced
6W x 2 (16Ω)
3W x 2 (32Ω)
440mW x 2 (300Ω)
220mW x 2 (600Ω)
SNR: 133dB, A-weighted
Output noise: 1.9uV, A-weighted
THD+N: -123dB, 0.00007% (1kHz, 32Ω)
THD+N: -117dB, 0.00013% (20-20kHz, 32Ω, -3dB)
THD: <-125dB, 0.00006%
Input impedance: 47kΩ
Output impedance: Near 0 Ω
Frequency Response: 0.1Hz - 500,000Hz(-3dB)
Power supply voltage/frequency: AC100-240V, 50-60Hz
