Stax Releases New SRM-400S Driver Unit for Earspeakers
Stax has a new solid-state energiser for its PRO-class electrostatic earspeakers. Designed to replace the stalwart mid-level SRM-353X, the SRM-400S sports a new FET-based DC amplifier stage with selected transistors, echoing the design of the high-end SRM-700S, the company says.
It also has a newly designed power transformer for the low voltage circuit winding, working alongside a conventional power transformer for the high voltage circuit. The former is claimed to improve power efficiency and sound quality. The new chassis is more rigid, with a resonance-reducing hybrid structure combining non-magnetic aluminium with pressed steel. Environmentally friendly, specially selected passive components are used, says the company, with no coupling condensers. There’s a choice of unbalanced RCA or balanced XLR line-level inputs around the back.
Stax says the new SRM-400S combines the fine sound balance of its predecessor with a higher resolution sound. This is claimed to be ideal for the company’s high-end Lambda series of earspeakers but also benefits its more affordable designs. Frequency response is quoted as DC to 90kHz, with a gain of 60dB and total harmonic distortion of less than 0.01% (1kHz, 100V rms output). Vital statistics are 195x102x376mm (HxWxD) and 3.4kg.
The Stax SRM-400S will be available in May 2021 and is expected to sell in Australia for around $2,100 RRP.
David started his career in 1993 writing for Hi-Fi World and went on to edit the magazine for nearly a decade. He was then made Editor of Hi-Fi Choice and continued to freelance for it and Hi-Fi News until becoming StereoNET’s Editor-in-Chief.