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Overview
The mk2 flagship RP headphones are carefully assembled one by one at a factory in Japan. The beautiful indigo color and texture of the wood grain of the housing, hand-dyed by skilled Awa Indigo craftsmen, combined with the overwhelming resolution and faithful expression of the premium RP drivers, provide an exquisite audio experience in which traditional craftsmanship and acoustic technology coexist.
The Premium RP Driver, developed using the largest diaphragm ever used in a fully driven planar diaphragm driver based on RP technology that has been refined since 1974, has been further optimized with mk2 technology through air damping control inside the driver, flow ad-justment using damping materials and new ear pads. This achieves ideal diaphragm amplitude, particularly in the low-frequency range. The Premium RP Driver’s large diaphragm and mag-netic circuit suppress unwanted resonance, delivering sharp response, high sensitivity, smooth frequency characteristics, and excellent transient response. Additionally, the mk2 version achieves the ability to faithfully and clearly reproduce sound images from the low-frequency range to the high-frequency range in space with precise localization.
The newly adopted ear pads in the mk2 feature a sloped design on the side that contacts the face, optimizing comfort. The internal low-density urethane foam is arranged in a two-layer structure, with a soft type on the outer side and a high-elasticity type on the inner side to con-form to the shape of the face. Additionally, the adoption of silk protein-based synthetic leather, which offers three times the durability of the previous model, ensures comfortable wear even during extended listening sessions.
The mk2 version uses a 2-pole 3.5 mm connector, improving re-cable compatibility and versatil-ity. The internal wiring and included unbalanced cable utilize 7N (99.99999%) grade high-purity OFC (Oxygen-Free Copper) cable, which minimizes impurities to maximize transmission per-formance. Additionally, a separate 4.4 mm balanced cable (ET-TH4.4BL2Y) is available for purchase.
Features
• Premium Open-Back Audiophile Headphones
• Flat-Diaphragm RP mk2 Planar Driver
• Hard Maple Housing, Hon-Ai Indigo Finish
• Smooth Frequency Response
• Excellent Transient Characteristics
• 32-Ohm Impedance
• Lightweight Magnesium Alloy Components
• Asymmetrical Silk-Protein Earpads
• Sheepskin Headband
• Detachable 7N Cable
What's In The Box?
• Fostex AMS-TH1100RPMK2 Premium Open-Back Planar Headphones for Audiophiles
• Leatherette Pouch
• Limited 1-Year Manufacturer Warranty
Generating expert take…
Fostex emerged in 1973 as the branded consumer and professional division of Foster Electric Co., Ltd., a Japanese loudspeaker manufacturer founded in 1949. Established to bring Foster's high-quality speaker components directly to dealers and customers, Fostex quickly gained international recognition through innovative products like the T20RP headphones and 6301 studio monitors. The brand's foundation rests on Foster's position as one of the world's largest OEM loudspeaker developers, employing tens of thousands across multiple countries and manufacturing millions of speaker units monthly.
The company built its reputation across three interconnected product categories: professional studio equipment, consumer headphones, and powered monitor speakers. Fostex became particularly renowned for pioneering RP (Regular Phase) technology, which delivers clear sound with high sensitivity and wide dynamic range—a signature that defines their headphones, microphones, and speaker designs. Beginning in 1978, the brand expanded into professional speaker development, eventually introducing the PM series of powered monitors and establishing itself as a trusted choice for recording studios, broadcast facilities, and serious home listeners.
Fostex occupies a distinctive middle ground in the audio market: neither ultra-premium boutique nor mass-market consumer, but rather a respected specialist brand with deep professional credentials. Their products appeal to recording engineers, studio owners, and discerning hi-fi enthusiasts who prioritize accuracy and reliability over luxury positioning. The 6301B monitor remains an industry standard after decades in production, while the T20RP headphones maintain popularity among studio professionals—testament to Fostex's enduring reputation for sonic integrity and engineering excellence.
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