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Regular price $629.99
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Amplifier type More information
Translation missing: en.products.product.amplifier_type_info


Connectivity More information
Connectivity refers to the method in which the headphones connect to the audio source. Headphones can be either wired or wireless.


Portability More information
DACs and amplifiers can either be carried around or meant for static desktop use

Not Portable

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Regular price $629.99
Sale price $629.99 Regular price $629.99

An SMSL classic gets a makeover  

The SMSL SP400 arrives just over a year after the release of its predecessor, the SP200.

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.

Power for all your headphones

But 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-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. 

Pure black background

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. 

To put these numbers in perspective, the loudness of a jackhammer is 110dB, an ambulance 120dB. So under any normal, healthy listening scenario with the SP400, you’re going to hear nothing but pure signal. 

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

  • 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

  • Power consumption (EN60065): <40W

  • Power consumption in standby mode: <0.1W

  • Size: 8.66 x 8.4 x 1.69” (220 x 215 x 43mm)

  • Weight: 2.9lbs (1330g)

What’s included

  • SMSL SP400

  • User Manual

  • Remote control

  • Power supply cord