STAX

Stax Ltd. (有限会社スタックス) is a Japanese maker of electrostatic audio equipment, founded in 1938. Throughout its history the company stuck to a single technology - the electrostatic transducer - and applied it to several product classes: headphones (which Stax has always called “earspeakers”), floor-standing loudspeakers, tonearms, phono cartridges, power amplifiers, CD players and DAC processors. Across thirty-six years of operations Stax shipped a full hi-fi line, not only headphones. In 1995 Stax became insolvent and was restructured in 1996 as the “new STAX company”. In December 2011 the Chinese loudspeaker manufacturer Edifier acquired 100% of Stax equity; the brand activity that followed has no direct continuity with Showa-era Stax.

What Stax is best remembered for from the Showa era is the world’s first electrostatic headphone. The SR-1 of 1960 has long been claimed as the earliest commercial electrostatic earspeaker. The company never moved away from the electrostatic principle: in place of magnets and voice coils, a thin diaphragm sits between two stators under a constant polarising voltage of around 580 V, which is supplied through a dedicated energizer amplifier or step-up transformer. Stax earspeakers physically will not work without their own line of driver units - unlike a conventional dynamic headphone - and the brand’s product range has always come in two parallel halves: the earspeakers themselves and the matching drivers. The same principle carried over to the ELS series of electrostatic loudspeakers, which dropped both the magnet assembly and the voice coil for a large thin-film panel held at high polarising voltage.

Showa-era Stax earspeakers ran the SR model code: the SR-Sigma, with its unusual forward-facing transducer geometry sitting in front of the ear (Sigma Professional at ¥46,000); the SR-Lambda main line, capped by the SR-Lambda Signature at ¥41,500 and SR-Lambda Professional at ¥32,000; the SR-alpha (PRO Excellent at ¥29,000); and the smaller SR-80MX and SR-84Pro. Drivers came in two flavours: passive SRD step-up transformer adapters (the SRD-7/MK2 and SRD-6SB) for use with the speaker terminals of an existing power amplifier, and active SRM electronic units - the SRM-X PRO class-A at ¥45,000, the push-pull SRM-1/MK2 PP at ¥65,000 and the tube-based SRM-T1 at ¥80,000. Beyond the earspeakers Stax built DAC processors (the 18-bit 8× oversampling DAC-X1t New at ¥850,000), CD players with built-in DAC (the CDP QUATTRO II at ¥310,000), power amplifiers without overall negative feedback (the NON-NFB DMA-X2, 600 W per channel, at ¥850,000), the UA series of tonearms, TIPTOES conical isolation feet, PC-OCC monocrystal-copper cables and the EK-1/MK-2 self-build electrostatic loudspeaker kits. The ELS-series electrostatic floor speakers headed the catalogue: the ELS-F81X at ¥300,000, the ELS-F83X at ¥500,000, the ELS-8X at ¥684,000 and the ELS-8X-BB with integrated base at ¥850,000 per cabinet.