Welcome to our STAX - SRM-D50 - Driver Unit Review, where we dive deep into STAX's latest compact desktop amplifier/DAC designed exclusively for electrostatic headphones. With its ESS ES9018 DAC, TI OPA1642 ultra-low distortion op amp, and discrete amplifier heritage, the SRM-D50 promises to redefine clarity, detail and musicality on your desk.

Key Specifications

• Frequency response: DC-40kHz (+0dB, -3dB)
• Harmonic distortion: <0.025% (1kHz-10kHz)
• Gain: 59dB (900x)
• Maximum output voltage: 400Vr.m.s (1130V p-p)
• Input options: USB, optical fibre, coaxial digital, RCA analogue
• ESS ES9018 DAC & TI OPA1642 op amp
• Supports DSD128 & PCM up to 384kHz
• Discrete amplifier circuitry with heritage from classic STAX designs
• Full aluminium housing with velvet-like finish and dancing voltage meter

Performance and Sound Quality

The SRM-D50 drives STAX electrostatic headphones with astonishing precision. From the deepest sub-bass rumble to the most delicate cymbal shimmer, the sound remains controlled, extended and utterly natural. The bit-perfect ESS ES9018 DAC ensures every recording nuance is laid bare, while the TI OPA1642 op amp maintains ultra-low distortion. Whether you're exploring DSD128 recordings or high-res PCM at 384kHz, expect a coherent soundstage with exceptional depth and air.

Design, Build Quality & Usability

Crafted from solid aluminium with multiple surface treatments, the SRM-D50 exudes refinement. The discrete component amplifier layout is visible through refined vents, and the iconic STAX voltage meter dances gracefully with the music, offering a visual cue to the electrical dynamics at play. Despite its desktop footprint, the unit remains compact enough for any setup.

Connectivity and Features

The SRM-D50 offers versatile connectivity: USB for high-res PC audio, optical and coaxial for dedicated digital sources, plus an RCA analogue input for legacy equipment. The XMOS USB interface supports seamless DSD128 playback, ensuring compatibility with leading audio platforms. Front-panel volume control is precise, with 59dB gain that suits both sensitive and demanding headphones.

Who Will Love the SRM-D50?

If you own STAX electrostatic headphones—be it the SR-L5000, SR-007A or SR-X9000—the SRM-D50 is your perfect companion. Its desk-friendly size and audiophile feature set make it ideal for dedicated listening rooms, home studios or anyone seeking the purest headphone experience without compromise.

Pros and Cons

Pros

• Exceptionally transparent and detailed sound with wide bandwidth
• Versatile inputs: USB, optical, coaxial and RCA analogue
• Dancing voltage meter adds a visual dimension to listening
• Robust aluminium chassis with premium finish
• Supports DSD128 and high-res PCM up to 384kHz

Cons

• No balanced inputs (RCA analogue only)
• Dedicated to STAX electrostatic headphones—no standard headphone jack

Ready to Transform Your Listening Experience?

The STAX SRM-D50 Driver Unit is a game-changer for electrostatic headphone enthusiasts. Speak with our team at The Audio Tailor for bespoke advice—call us on 1300 308 711 or email sales@theaudiotailor.com.au. Discover more details and secure yours today on our product page: STAX SRM-D50 Driver Unit.

Our specialists—Gabby, Nathan, Vaughan and Isaac—are ready to guide you towards the ultimate electrostatic experience.