STAX is out with a new portable audiophile headphone amp

Reading Time: 5 minutes

STAX just introduced the SRM-D10 II portable headphone amplifier, available for sale from the first quarter of 2024. Featuring significant updates from the original SRM-D10, the SRM-D10 II continues to elevate listening experiences for STAX fans worldwide.

The SRM-D10 II is a result of STAX’s commitment to pushing the boundaries of audio technology. It incorporates cutting-edge features, meticulously crafted components, and a sleek design to provide audiophiles and professionals with a listening experience like no other.

“As we continue to celebrate STAX’ 85^th anniversary, it is a timely reminder of how far the brand has come in its pursuit of audio excellence. The SRM-D10 II showcases an upgraded decoder chip from its predecessor, the AKM4493 for an improved audio processing and enhanced sound performance,” said Douglas Ip, Head of Sales & Marketing, STAX International.

“This release shows our dedication to improving STAX transportability as well, so that the STAX listener has the option to carry their in-ears or earspeakers with a quality portable amp. Ideally, this new iteration of the STAX portable amplifier will become a part of their audiophile toolbox.”

STAX's new headphone amp — STAX’s new headphone amp

STAX SRM-D10 II Key Features:

Enhanced Sound Quality: The SRM-D10 II utilizes hardware decoding and high-quality audio capacitors to deliver unparalleled sound quality, ensuring every note is crisp and every detail is vivid.
DSD and PCM Support: With support for DSD sampling rates up to DSD256 and PCM sampling rates up to 384kHz/32bit, the SRM-D10 II can faithfully reproduce high-resolution audio formats, preserving the artist’s original intention.
High-Quality Power Amplifier: The SRM-D10 II is equipped with a high-quality power amplifier, providing outstanding performance and remarkable power, allowing you to experience music in its purest form.
High Voltage Output: A robust DC 580V DC bias enhances the amplifier’s output, resulting in a more dynamic and powerful soundstage.
Rugged Aluminium Alloy Shell: The aluminum alloy shell not only exudes a sleek, modern design but also offers higher strength and corrosion resistance, ensuring the SRM-D10 II is built to last.
Versatile Connectivity: The SRM-D10 II supports both USB digital and 3.5mm analog audio inputs, offering flexibility in connecting to a wide range of devices.
Compatibility: Designed to complement all STAX PRO-type headphones, the SRM-D10 II ensures that you can enjoy the full potential of your earspeakers.

Specifications:

Rated input level: 230mV (100V output)
Maximum input level: 10V (minimum volume in Line In input)
Gain: 53dB (450 times)
Harmonic distortion: ≤0.025% / 1kHz-10kHz
Input impedance: 10KΩ (Line In input)
Maximum output voltage: 200Vr.m.s / 100Hz-10kHz
Supply voltage: DC 5V/9V/12V/15V
Power consumption: 6.4W (USB input) 5W (Line In input)

DSD Support: Up to DSD256
PCM Support: Up to 384kHz/32bit
Amplifier: High-Quality Power Amplifier
Output Bias: DC 580V
Shell Material: Aluminium Alloy
Input Options: USB Type-C, 3.5mm Analog
Compatibility: Suitable for all STAX PRO-type headphones

The Audiophile History of STAX Headphones from Japan

STAX is one of the most revered names in the world of high-end personal audio. Known for their pioneering work in electrostatic headphone technology, STAX headphones (or more accurately, “earspeakers,” as the company prefers to call them) have become legendary among audiophiles for their transparency, speed, and uncolored presentation. Based in Japan and founded in the late 1930s, STAX has walked its own path in headphone design, and their products have remained uniquely positioned in the high-fidelity landscape for decades.

The company was originally established in 1938 as a manufacturer of audio equipment, but it wasn’t until 1960 that STAX made its mark on the world of personal audio with the release of the SR-1, the world’s first commercially available electrostatic headphone. This was an era when dynamic headphone drivers were the norm, and STAX’s radically different approach turned heads—quite literally. The SR-1 used a thin, electrically charged diaphragm suspended between two perforated metal plates. When an audio signal was applied, the diaphragm moved in response to the changing electric field, producing sound with incredibly low distortion and astonishing detail.

From the beginning, STAX emphasized clarity, accuracy, and speed over the more common goals of power or impact. Electrostatics behave very differently than dynamic drivers. They have almost no moving mass, so they can start and stop much faster, which gives them a level of transparency that many headphone designs struggle to match. But electrostatics also come with challenges—they require a dedicated energizer or electrostatic amplifier, since they operate at much higher voltages than conventional headphones. This limited STAX’s market appeal to more serious or technically inclined listeners, but also ensured that their audience remained deeply loyal.

Throughout the 1970s and 1980s, STAX expanded its product line with models like the SR-X series and later the Lambda models, which introduced the signature open-back, rectangular earcup design that has since become visually synonymous with the brand. These earspeakers delivered a broad, airy soundstage and extremely detailed midrange, making them favorites among classical music lovers and mastering engineers alike. The Lambda Pro, released in the mid-1980s, marked another leap in performance and helped solidify STAX’s place as a top-tier headphone manufacturer.

The company went through changes in ownership and financial challenges in the 1990s, and in 1995 it was reorganized under new management as STAX Ltd. Despite the instability, the core engineering team remained, and product development continued. In 2011, STAX was acquired by the Chinese conglomerate Edifier, which pledged to maintain STAX’s identity and commitment to Japanese manufacturing. Edifier’s support provided STAX with the financial backing to improve quality control, modernize facilities, and expand global distribution—without fundamentally altering the company’s design philosophy.

In recent years, STAX has continued to evolve, introducing models like the SR-009 and SR-009S, which are widely regarded as some of the best headphones ever made. These earspeakers push electrostatic technology to its limits, offering even better diaphragm materials, more advanced stator design, and improved structural rigidity. Paired with matching high-voltage amplifiers like the SRM-T8000, these systems are often considered reference-class by headphone reviewers and serious audiophiles alike.

At the same time, STAX has also worked to bring electrostatic listening to a wider audience with more approachable models like the SR-L300 and SR-L500, which maintain the company’s design ethos at more manageable price points. Even these lower-cost offerings retain the speed and transparency STAX is known for, making them an appealing alternative to traditional dynamic or planar magnetic headphones.

Despite trends toward wireless audio, portable listening, and digital convenience, STAX has never deviated from its core mission. Their products require careful system matching, dedicated amplification, and often a fixed listening position—making them less flexible than many modern alternatives. But for listeners who prioritize sonic realism, low distortion, and effortless detail, STAX remains a gold standard.

STAX’s legacy is one of quiet excellence. They don’t advertise heavily or chase mainstream trends. They don’t build lifestyle products or dabble in Bluetooth. What they do is electrostatics—only electrostatics—and they’ve been refining that formula for over 60 years. In doing so, they’ve built one of the most respected reputations in audiophile history.

For those who consider music listening a serious, focused experience—less about background noise and more about immersion—STAX offers a uniquely pure connection to sound. And while they may never dominate the mass-market headphone space, their place in the high-end world remains secure: a quiet giant from Japan, doing one thing exceptionally well.