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The M400 sits in SMSL’s upper-tier DAC lineup, and at US$375 this listing lands above your US$334 75th percentile, so it reads as ambitious rather than a bargain. It is not wildly out of line for a premium feature set, but it is priced at the top end of what the recent used market has been tolerating.
What makes it appealing is straightforward: it’s a well-regarded, fully balanced AK4499-based DAC with MQA and Bluetooth, and the model has a good reputation for clean, detailed, low-noise playback. If the unit is genuinely clean, fully functional, and comes with the original remote/box/power supply, that helps justify the ask; otherwise, I’d want more proof of condition before paying this much.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
MQA emerged in December 2014 from the innovative labs of UK-based Meridian Audio, founded by digital audio pioneer Bob Stuart. As a proprietary codec—Master Quality Authenticated—MQA was designed to deliver studio-master sound quality through efficient encoding, folding high-resolution audio up to 192kHz into standard 44.1kHz files while addressing perceived timing inaccuracies in digital playback. Meridian, renowned for its high-res contributions like the MLP format for DVD-Audio, spun off MQA as an independent company, MQA Limited, to champion this streaming-era solution.
Unlike traditional hi-fi hardware makers, MQA focuses exclusively on audio technology licensing rather than physical products like amplifiers, speakers, or turntables. Its core offerings include encoders for labels, decoders integrated into DACs, streamers, and apps, plus extensions like the Arya Bluetooth codec (formerly SCL6/MQAir) for wireless high-res transmission. Bluesound, NAD, and PSB products have prominently featured MQA decoding, embedding the tech into high-performance streaming DACs and amplifiers.
Positioned as a high-end niche player, MQA garnered initial acclaim for promising authenticated artist-intended sound but faced fierce debate over its claims of superior fidelity and lossless efficiency, dividing engineers and reviewers. After administration in April 2025, Lenbrook Industries—owners of NAD, PSB, and Bluesound—acquired its assets, signaling potential revival and renewed integration into premium hi-fi ecosystems for discerning streaming enthusiasts.
See all MQA listings on RADAR.
