Stax
Japanese high-end electrostatic headphone brand known for electrostatic headphone systems.
Last updated October 15, 2026
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Overview
Stax Ltd. is a Japanese high-end audio company whose identity is closely associated with electrostatic headphones and matching amplifiers. Rather than using the more common headphone terminology, Stax calls many of its products “earspeakers,” emphasizing their relationship to electrostatic loudspeakers and their focus on spacious, highly detailed reproduction. The company’s products use an electrically charged diaphragm suspended between stators. When driven by a suitable high-voltage amplifier, the diaphragm moves in response to the audio signal, producing sound without the conventional dynamic-driver arrangement used in most headphones. The company was founded in 1938, although its defining technological direction emerged much later. In 1960, Stax introduced the SR-1, identified as its first electrostatic earspeaker. The product established the basic category in which Stax would become particularly influential and provided the foundation for decades of specialized headphone and amplifier development. Over the following decades, the company expanded beyond earspeakers into related high-end audio equipment, including electrostatic amplifiers, tonearms, compact-disc players, digital-to-analog converters, phono cartridges, and loudspeakers. Stax’s headphone history includes several recognizable product families. The Lambda design became one of its best-known formats and continued to influence the company’s lineup through models such as the SR-L300, SR-L300 Limited, SR-L500, and SR-L700. The Omega family represented a more ambitious flagship direction, including the SR-007, SR-007A, and SR-009. In December 2022, Stax introduced the SR-X9000 as a new flagship earspeaker. The company has also produced compact in-ear electrostatic models and a closed-back model, the 4070, intended primarily for studio and broadcast use. Stax products require dedicated amplification and are not interchangeable with ordinary headphone systems. The company’s earspeakers use two principal bias standards: an older 230-volt Normal-bias system and a later 580-volt Pro-bias system. The connector arrangements differ, and the electrical mismatch means that users must pair earspeakers with compatible amplifiers. Current products use the Pro-bias standard, while Normal-bias models are historical products that largely disappeared from production around the early 1990s. Stax experienced a major corporate disruption in 1995, when the company became insolvent. It was revived in 1996 as a new STAX company, allowing the brand and its specialist product expertise to continue. In December 2011, Chinese audio-equipment manufacturer Edifier announced that it had acquired all of Stax’s equity. Under Edifier ownership, Stax has continued to operate as a specialist premium audio brand rather than being repositioned as a mass-market headphone label. Its portfolio remains centered on electrostatic earspeakers, dedicated amplifiers, and accessories such as extension cables and headphone stands. Stax occupies a distinctive position in the international high-end audio market. Its products appeal to listeners who value electrostatic technology, resolution, low-distortion reproduction, and the brand’s long technical heritage. The trade-off is a comparatively specialized ecosystem: earspeakers need appropriate amplifiers, and the different bias standards require attention to compatibility. This combination of technical specialization, premium pricing, and a narrow product category gives Stax a strong identity among audiophiles while limiting its familiarity among general headphone consumers.
History
Stax Ltd. was established in Japan in 1938. The company’s early history is not extensively documented in the supplied reference material, but its later identity was shaped by the development of electrostatic audio technology. In 1960, Stax released the SR-1, described as its first electrostatic earspeaker. This product placed the company at the forefront of a highly specialized form of personal audio and established the technical direction for much of its subsequent work. Electrostatic earspeakers operate on a different principle from conventional dynamic headphones. A thin diaphragm is suspended between electrically charged stators, and variations in the audio signal cause the diaphragm to move. Because the system requires a dedicated high-voltage bias and suitable amplifier circuitry, Stax developed not only earspeakers but also the amplifiers needed to drive them. This integrated approach became a defining characteristic of the brand. During the decades after the SR-1, Stax broadened its product activity across high-end audio. In addition to earspeakers and amplifiers, the company produced tonearms, compact-disc players, digital-to-analog converters, phono cartridges, and loudspeakers. These products placed Stax within the wider Japanese audiophile component industry, although electrostatic earspeakers remained its most distinctive contribution. The Lambda family became one of the company’s most recognizable designs. Its large, open-back form provided a platform for multiple generations, including the SR-L300, SR-L300 Limited, SR-L500, and SR-L700. Stax also developed higher-end Omega-series products. The SR-007 and SR-007A preceded the SR-009, which served as a flagship model for the brand. A separate 4070 model used a closed-back configuration and was aimed primarily at studio and broadcast applications. Stax also experimented with smaller electrostatic in-ear formats. The SR-001, SR-001mk2, SR-002, SR-003, and SR-003mk2 represented attempts to bring the company’s electrostatic approach to more compact systems. Some models used proprietary connections with matching battery-powered amplifiers, while the SR-003 series used the Pro-bias connection intended for standalone electrostatic amplification. A major break in the company’s history occurred in 1995, when Stax became insolvent. The business was revived in 1996 as a new STAX company. This restructuring preserved the brand’s specialist focus and enabled continued development of electrostatic earspeakers and amplifiers. In December 2011, Edifier, a Chinese loudspeaker and audio-equipment manufacturer, announced the acquisition of 100 percent of Stax’s equity. The acquisition placed Stax within the Edifier group while retaining its identity as a premium electrostatic-audio specialist. The company’s subsequent range continued to center on earspeakers, dedicated amplifiers, and related accessories. Stax’s technical history also includes the transition from Normal-bias to Pro-bias operation. Earlier earspeakers used a 230-volt Normal-bias standard and a six-pin connector. Later products adopted a 580-volt Pro-bias standard with a five-pin connector. The two systems are not equivalent, and the voltage difference makes correct amplifier and earspeaker matching important. By the modern period, Stax’s current earspeakers used Pro bias, while Normal-bias models remained part of the historical product record. In December 2022, Stax introduced the SR-X9000 as a new flagship model. As of the supplied 2020 product information, the lineup comprised seven electrostatic earspeakers, seven electrostatic amplifiers, and accessories including extension cables and a headphone stand. Stax therefore remains a focused, technically specialized brand serving the high-end audio and audiophile markets.
- 2022
SR-X9000 flagship introduced
[1]Stax introduces the SR-X9000 in December as a new flagship electrostatic earspeaker.
- 2020
Documented contemporary lineup
[1]The reported lineup consists of seven electrostatic earspeakers, seven electrostatic amplifiers, and related accessories.
- 2011
Acquisition by Edifier
[1]Edifier announces the acquisition of 100 percent of Stax’s equity.
- 1996
Corporate revival
[1]The brand is revived through a new STAX company.
- 1995
Insolvency
[1]Stax becomes insolvent after decades in the specialist high-end audio business.
- 1992
Normal-bias production approaches its end
[1]The last Normal-bias Stax earspeakers are reported to have left production around this period, marking the transition toward the later Pro-bias standard.
- 1960
Introduction of the SR-1
[1]Stax releases the SR-1, identified as its first electrostatic earspeaker and an important foundation for the company’s signature product category.
- 1938
Stax is founded
[1]Stax Ltd. is established in Japan and begins the corporate history that later leads to its specialization in electrostatic audio.
Products and positioning
A specialist Japanese high-end audio brand focused on electrostatic earspeakers and the dedicated amplification required to operate them. Stax emphasizes technical refinement, detailed sound reproduction, long product heritage, and a premium audiophile experience rather than mass-market accessibility.
Electrostatic earspeaker · 1960
SR-1
Introduced in 1960, the SR-1 is identified as Stax’s first electrostatic earspeaker. It established the company’s signature approach to personal audio, using an electrostatic transducer rather than a conventional dynamic driver. The model is historically important because it set the direction for the brand’s later headphones, amplifiers, and technical vocabulary.
Electrostatic earspeakers
Lambda series
The Lambda family is one of Stax’s most recognizable earspeaker designs. Modern models based on the classic format include the SR-L300, SR-L300 Limited, SR-L500, and SR-L700. The family represents Stax’s continuing use of a broad, open electrostatic headphone configuration and serves as a central part of the company’s high-end lineup.
Flagship electrostatic earspeakers
SR-007 and SR-007A
The SR-007 and SR-007A belong to Stax’s Omega-related high-end earspeaker lineage. They preceded the SR-009 as flagship products and are designed for use with compatible Stax electrostatic amplification. Their place in the range reflects the company’s emphasis on premium construction, specialized drive requirements, and audiophile-oriented performance.
Flagship electrostatic earspeaker
SR-009
The SR-009 is an Omega-series flagship earspeaker and the successor to the SR-007 and SR-007A in Stax’s premium hierarchy. It exemplifies the brand’s high-end electrostatic design philosophy and requires a dedicated compatible amplifier. The model was positioned at the top of Stax’s range before the later introduction of the SR-X9000.
Flagship electrostatic earspeaker · 2022
SR-X9000
Introduced in December 2022, the SR-X9000 is a flagship Stax electrostatic earspeaker. It continues the company’s premium product strategy and is designed to operate with the brand’s dedicated electrostatic amplification ecosystem. The model represents the modern continuation of Stax’s top-tier earspeaker development.
Lambda-series electrostatic earspeakers
SR-L300, SR-L300 Limited, SR-L500, and SR-L700
These four models are modern earspeakers based on Stax’s classic Lambda design. They provide several levels within the company’s open-back electrostatic range and use the Pro-bias standard associated with current Stax products. Their shared design language links contemporary offerings with one of the brand’s best-known historical product families.
Electrostatic in-ear monitors
SR-001, SR-001mk2, SR-002, SR-003, and SR-003mk2
This group represents Stax’s compact in-ear electrostatic experiments. The SR-001, SR-001mk2, and SR-002 used proprietary connections and were intended to work with matching battery-powered electrostatic amplifiers for portable systems. The SR-003 and SR-003mk2 used a standard Pro-bias plug for connection to a standalone electrostatic amplifier. The SR-003 MK2 was identified as the production model in the supplied reference.
Closed-back electrostatic earspeaker
4070
The 4070 is a closed-back electrostatic earspeaker intended primarily for studio and broadcast applications. Its enclosed construction distinguishes it from Stax’s more familiar open-back designs and reflects an effort to adapt the company’s electrostatic technology to professional monitoring contexts.
Headphone amplifiers
Stax electrostatic amplifiers
Stax produces dedicated amplifiers for its electrostatic earspeakers. These amplifiers supply the specialized electrical drive and bias requirements that ordinary headphone amplifiers cannot provide. The range is closely tied to the earspeaker lineup and includes support for the later 580-volt Pro-bias standard, while older equipment may relate to the 230-volt Normal-bias system.
Controversies
Brand decisions
2022
Launch of the SR-X9000Product launchBackground
Stax’s product heritage includes the SR-007, SR-007A, and SR-009 Omega-series flagship earspeakers.
Action taken
Stax introduced the SR-X9000 in December 2022 as a new flagship electrostatic earspeaker.
Aftermath
The launch extended Stax’s premium flagship line and maintained its focus on dedicated electrostatic listening systems.
2011
Sale of 100 percent equity to EdifierM&ABackground
Stax was operating as a specialist Japanese electrostatic-audio company following its 1996 revival.
Action taken
Edifier announced the acquisition of all of Stax’s equity in December 2011.
Aftermath
Stax became part of the Edifier group while continuing to operate under its own specialist brand identity.
1996
Re-establishment as a new STAX companyStrategyBackground
Stax became insolvent in 1995 after operating for decades as a specialist high-end audio manufacturer.
Action taken
The business was revived in 1996 as a new STAX company, preserving the brand’s focus on electrostatic audio products.
Aftermath
The revived company continued developing earspeakers, amplifiers, and related high-end audio products.
Recent events
- Unconfirmed
Investor group acquires Stax[2]
Reported:
A private Australian investor group led by Justin Truong and Sandy Li-Truong acquired activewear brand Stax out of receivership, including its trademarks, design intellectual property, Nandex™ fabric technology and digital assets.
Stax announces acquisition of CardX[3]
Reported:
Stax announced its acquisition of CardX, an automated surcharging platform. CardX will continue to operate as a stand-alone brand alongside the Stax platform.
Edifier launches STAX SPIRIT S3 headphones[4]
Edifier formally launched the STAX SPIRIT S3 over-ear planar-magnetic Bluetooth headphones on September 24, 2021, priced at 898 yuan.
Sources4 sources
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