STAX SRM-252S Direct Coupled Class-A Energiser


Trade-in available

Designed exclusively for driving STAX Earspeakers (headphones) featuring the PRO-bias 5-pin connectors, the SRM-252S from STAX Audio features a clear, simple design that excels in sound quality.

The unit employs carefully-selected late-model high-voltage transistors and low-noise FETs to deliver excellent electrostatic reproduction of any audio signal.

SKU: USV-STAX-SRM252S Categories: , , Tag:



The SRM-252S from STAX Audio is an exclusive driver unit (amplifier) for driving STAX earspeakers with PRO-bias 5-pin connections. With a clear, simple design that excels in sound quality, SRM-252S employs carefully-selected late-model high-voltage transistors and low-noise FETs.

Class-A amplification with no coupling capacitors allows for the finest reproduction of each nuance of the music.

Although the SRM-252S includes a class-A DC amplifier in a compact case, the internal heat is effectively dissipated through the aluminium chassis, improving reliability and longevity.

The line input of SRM-252S can directly connect to the audio output of CD players, portable audio players and computers, whilst the output stage with emitter-follower configuration reinforces the driving performance and smooth sound quality.

A parallel output terminal has also been added, distributing the source signal. This means that a loudspeaker may be simultaneously connected when your source equipment has only one pair of output terminals.


  • Frequency response: DC 35kHz (40V RMS output SR-207, when using one unit)
  • Rated input level: 125mV with 100V output
  • Maximum input level: 30V RMS with volume at minimum setting
  • Amplification: 58dB (x800)
  • Total harmonic distortion: max. 0.01% (1 kHz / during 100V RMS output)
  • Input impedance: 50kΩ (RCA)
  • Maximum output voltage: 280V RMS / 1kHz
  • Standard bias voltage: DC580V (PRO-bias)
  • Power consumption: DC12V / 4W – AC adaptor included
  • Temperature range for use: Between 0°C and 35°C, max. 90% (no condensation)
  • External dimensions: 132 (W) × 38 (H) × 132 (D) mm
  • Weight: 540g

More Information



Founded in 1938, STAX brought the world's first electrostatic headphone to market in 1960 and today continues their long tradition by offering the finest products for both professional and audiophile applications.

All STAX headphones are referred to as "earspeakers" - the company states that such ultra-high fidelity devices can only be compared with the best cost-no-object loudspeakers, not other headphones. Their unique amplifiers, earspeakers and drivers are highly sought-after products, and extremely well considered by aficionados in the audio industry.

Unilet Sound & Vision are one of the oldest STAX dealers in the UK, and one of the very few official outlets for their products.

STAX | Unilet Sound & Vision

Additional information

Weight 0.54 kg
Dimensions 13.2 × 13.2 × 3.8 cm


Purchase Options

Click & Collect, Trade-In Available


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