STAX SRM-D50 DRIVER/ DAC & SR-L500 EARSPEAKERS
Legendary. It’s a powerful and emotive word, and it is one that every audiophile I have ever spoken to uses when they are talking about Stax headphones… or, as Stax prefers to call them… ‘earspeakers’.
In fact, the unique design of nearly all Stax headphones is such that calling them earspeakers is actually highly appropriate, because in reality, they are essentially miniaturised full-sized loudspeakers… even the shape of the headpiece is rectangularly reminiscent of a loudspeaker cabinet, rather than the circular form usually employed for headphones. (I wrote ‘nearly all’ in that sentence because the three most expensive—and most recently designed—models in the Stax range have circular, rather than rectangular, earpads. Traditionally, however, Stax headphones had rectangular ear pads.)
But what makes Stax earphones truly unique is that whereas almost all headphones currently available for sale use one type of dynamic driver element or another (where a coil of wire interacts with a magnetic field in some way to move a diaphragm to create sound) Stax earspeakers instead use high-voltage electrical charges to move the diaphragm. You may well ask: ‘How high a voltage?’ To which the answer would be ‘around 400 volts a.c. for the drive voltage as well as around 600 volts d.c. for the bias voltage’, according to Stax. The design is called ‘electrostatic.’
But how do you safely create such high voltages? With what Stax calls a ‘driver’, of which the SRM D50 Driver/DAC is the newest addition to the Stax driver line-up.
THE EQUIPMENT
Since it has been in the business of building electrostatic (ES) earspeakers since 1960, and all earspeakers require special electronics to ‘drive’ them, Stax has also been building ‘drivers’ since 1960. Of the models in the current range, the flagship is the SRM-T8000 ($7,999) and the entry-level model is the battery-powered SRM-D10 ($1,499) which is also the only other model in Stax’s range that incorporates an inbuilt digital-to-analogue converter. Indeed it appears the success of the SRM-D10 was one reason Stax developed the SRM-D50 in the first place, because, according to this Japanese company, it was ‘.’ Stax has obviously taken note of the huge resurgence in the popularity of
