SMSL H400 MK2 Fully Balanced Headphone Amplifier & Preamplifier with PLFC+ GaN Power

Features

• Fully Balanced PLFC+ Architecture — Patented 4-channel fully balanced headphone amplifier circuit delivers powerful and precise amplification.
• 14 OPA1612A Op-Amps — High-performance analog circuitry provides exceptionally clean and detailed signal reproduction.
• 18W Output Power — Delivers up to 18W per channel at 16Ω and 9W per channel at 32Ω for demanding headphones.
• Ultra-Low Distortion — Achieves THD+N as low as 0.00006% with a 132dB signal-to-noise ratio.
• High-Power GaN Power Supply — Custom low-noise GaN power supply provides clean and stable power for the amplifier.
• Precision Relay Volume Control — Electronic relay step control provides accurate volume adjustment and excellent left-right channel tracking.
• 3-Gain Control — Optimized gain settings support both high-power headphones and sensitive IEMs, with low gain down to -5.5dB balanced and -11.5dB unbalanced.
• Multiple Headphone Outputs — Includes 4.4mm balanced, 4-pin XLR balanced, and 6.35mm single-ended outputs.
• Balanced Preamp Outputs — XLR and RCA pre-outs allow the H400 MK2 to function as a high-end preamplifier for active speakers.
• Grounding Control — Floating/Grounded switch provides flexible system grounding options.
• Fully Laminated Color IPS Display — Provides a clear and refined interface in a compact desktop chassis.

Overview

The SMSL H400 MK2 is a fully balanced desktop headphone amplifier designed to deliver exceptional power, precision, and control for demanding headphones. Featuring SMSL's patented PLFC+ fully balanced 4-channel amplifier circuit and 14 OPA1612A operational amplifiers, it combines powerful output with an exceptionally low THD+N of 0.00006% and a 132dB signal-to-noise ratio.

A high-power, low-noise GaN power supply provides a clean and stable foundation for the amplifier, while the high-precision electronic relay volume control ensures accurate channel tracking even at low listening levels. Three gain levels, including an ultra-low gain setting, allow the H400 MK2 to work comfortably with both demanding headphones and sensitive IEMs.

Beyond headphone amplification, the H400 MK2 also functions as a high-end preamplifier with balanced XLR and RCA pre-out outputs. Combined with 4.4mm, 4-pin XLR, and 6.35mm headphone outputs, grounding control, and a compact desktop design with a fully laminated color IPS display, it offers a versatile solution for both headphone and active-speaker systems.