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Elevate your audio experience with the Stax SRM-400S Electrostatic Headphone Amplifier Driver Unit. Renowned for its high-end performance, this amplifier is a staple for audiophiles seeking precision and clarity in their sound. The sleek silver design is not only aesthetically pleasing but also h...
Unknown condition makes the A$1,800 asking price hard to judge as a bargain, but it sits comfortably below the 75th percentile of A$2,236 and is solidly above the median of A$1,284, so call it fair-to-ambitious depending on wear. If the unit is clean and original-owner, A$1,800 is a reasonable entry into Stax electrostatic drive; if it shows age or has unknown history, the price leans ambitious compared to the median.
The SRM-400S is well-regarded for its 60dB gain, sub‑0.01% harmonic distortion, and 400V output, bridging the SRM‑353X and SRM‑700S with 700S‑derived tech at a 353X‑like price point. It powers Stax electrostatic headphones cleanly and is a timeless workhorse for the system. Upside includes rarity in the used market and the chance to pair it with SRM‑series earspeakers; only flag caveats if the unknown condition suggests age issues or missing accessories, otherwise treat a clean listing at this price as a buying opportunity.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Stax traces its origins to 1938 in Tokyo, Japan, when Naotake Hayashi founded Showa Kouon Co., Ltd. in Chiyoda-ku. Initially focused on wax disc recording, metal master production, and audio equipment for film soundtracks, the company evolved through the postwar era. In 1950, it launched its first high-frequency condenser microphone, adopted by NHK, and renamed itself STAX Co., Ltd. in 1963, honoring its pioneering Stax-1 mic. A brief suspension in 1995 due to economic pressures gave way to revival, preserving its legacy under family leadership.
The brand specializes in electrostatic headphones, known as "EARSPEAKERS," debuting with the world-first SR-1 in 1960. This innovation spawned enduring lines like the SR series, produced for decades with incremental refinements for superior resolution and staging. Stax complements these with dedicated electrostatic amplifiers and select accessories, eschewing conventional speakers, turntables, DACs, or cables to hone its transducer expertise.
Stax commands a niche high-end position among audiophiles and professionals, revered for unmatched transparency and fidelity that rivals cost-no-object loudspeakers. Its 85-year heritage cements it as a boutique icon in electrostatic technology, far from mass-market fare, appealing to discerning buyers seeking pinnacle sonic transduction.
See all Stax listings on RADAR.
