STAX SRM-353X Solid State Headphone Energiser


Trade-in available

SRM-353X is a solid state headphone amplifier / driver unit (energiser) which works with all STAX electrostatic earspeakers.

With an added XLR for balanced output connection, a wider frequency response, and hand-selected high-quality audio grade parts, STAX have further improved this unit’s already excellent tonal quality.

SKU: USV-STAX-SRM353X Categories: ,



The SRM-353X is an exclusive solid state energiser (headphone amplifier / driver unit) for STAX electrostatic earspeakers.

STAX Audio have re-examined their circuitry to provide a wider frequency response, and have also carefully hand-selected high-quality audio grade parts to further improve tonal quality.

The newly added XLR input terminal enables connection to the balanced outputs of audio equipment, taking full advantage of the SRM-353X’s superior performance.


  • Original low noise dual FET first stage, all stage direct coupling Class A DC amplifier configuration with no coupling capacitor.
  • Improved emitter follower at output stage.
  • RCA input / XLR balanced input terminals.
  • Custom-made 2-axis, 4-gang volume control
  • Extravagant non-magnetic aluminum alloy chassis


  • Type: All-stage semiconductors, Low-noise dual FET input Class A operation, Pure balance DC amplifier configuration Earspeaker driver unit
  • Frequency Response: DC to 90,000Hz (with 1 SR-L series Earspeaker)
  • High Harmonic Distortion: Max 0.01% (1kHz at 100V RMS with SR-L500)
  • Gain: 60dB (x1000)
  • Input Terminal: 1 RCA with 1 RCA parallel out and XLR
  • Rated Input Level: 100mV / 100V Outputs
  • Max. Input Level: 30V (at minimum volume level)
  • Input Impedance: 50KΩ(RCA) 50KΩx2(XLR)
  • Max. Output Voltage: 400V RMS (1kHz)
  • Standard Bias Voltage: PRO 580V x 2
  • Power Voltage Frequency: 117V (50Hz / 60Hz)
  • Power Consumption: 30W
  • Temperature & Humidity: 0 to 35°C / 90% max. without condensation
  • Dimensions: 5.9 (W) x 3.9 (H) x 14.2 (D) in
  • Weight: 6.6lbs
  • Color : Silver
  • Voltage: 120V/60HZ
  • Warranty: 1-year U.S. limited warranty

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 2.99 kg
Dimensions 36.07 × 14.99 × 9.9 cm


Purchase Options

Click & Collect, Trade-In Available


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