Fostex TH900mk2 is a closed-back dynamic headphone — the direct predecessor to the open-back TH909 and the acoustic foundation of Fostex's entire flagship TH-series. The 50mm BioDyna driver with 1.5 Tesla neodymium repulsion magnet circuit is the same driver type as in the TH909, housed in a closed acoustic chamber with a precisely tuned acoustic path. The closed architecture gives the TH900mk2 a distinct sonic identity from the TH909: a more intense, deeply anchored bass, a more focused soundstage, and passive environmental isolation. The Japanese ornamental cherry birch housing is finished in bordeaux Urushi lacquer by the Sakamoto factory. A headphone stand is included. Hand-assembled in Japan.
Closed chamber with 1.5 T repulsion circuit: acoustic pressure as a bass-shaping tool
The 50mm BioDyna driver with repulsion magnet circuit at 1.5 Tesla magnetic flux density is one of the strongest magnetic circuits applied in dynamic headphones of this class. The repulsion circuit provides a symmetrical magnetic field on both sides of the diaphragm, reducing distortion at high amplitudes and enabling controlled low-frequency reproduction without breakup. The closed acoustic chamber of the TH900mk2 builds pressure on the inner side of the earcup — delivering a strong, deep bass foundation with the dynamic speed and transient precision characteristic of the Fostex TH-series. The BioDyna diaphragm in bio-cellulose and composite fibers with a free-edge design provides linear reproduction of large amplitudes in the low midrange, a natural midrange, and a precise high-frequency range extending to 45,000 Hz. Frequency response: 5–45,000 Hz, impedance: 25 Ω, sensitivity: 100 dB/mW, maximum input: 1,800 mW. Weight: approx. 385 g.
Bordeaux Urushi lacquer by Sakamoto, included stand and full flagship accessory package
The Japanese ornamental cherry birch housing is finished in bordeaux Urushi lacquer — handcrafted by artisans at the Sakamoto Otosho Shoten factory, established in 1900, applying traditional Japanese lacquering techniques to industrial production. Over a base black lacquer and adhesive layer, several types of sulfur-smoked silver foil are applied in a torn-paper manner, building the multi-layered bordeaux depth that is unique to each individual unit. Low-resilience urethane earpads covered in high-grade synthetic leather. Included cable: 3 m, 7N OFC, 6.3mm plug, 2-pin connector with rhodium-plated contacts. Balanced connection via the optional XLR cable (ET-H3.0N7BL). The full accessory package includes a headphone stand and a synthetic leather carrying bag — identical to the TH909, and the element that distinguishes the TH900mk2 from the TH900mk2LE which omits the stand. Manufactured and hand-assembled in Japan.
KEY FEATURES
- Closed-back dynamic design — foundation of the Fostex TH-series flagship line, predecessor to TH909
- 50mm BioDyna driver: bio-cellulose diaphragm, neodymium repulsion magnet circuit, 1.5 Tesla magnetic flux density
- Closed acoustic chamber — intense deep bass, focused soundstage, passive environmental isolation
- Japanese ornamental cherry birch housing with bordeaux Urushi lacquer (Sakamoto factory, est. 1900) — each unit unique
- Low-resilience urethane earpads + high-grade synthetic leather
- Included cable: 3 m, 7N OFC, 6.3mm plug
- 2-pin connector with rhodium-plated contacts
- Balanced XLR connection via ET-H3.0N7BL (sold separately)
- Included accessories: headphone stand + synthetic leather carrying bag
- Hand-assembled, manufactured in Japan
TECHNICAL SPECIFICATIONS
- Type: closed-back, over-ear, dynamic
- Driver: 50mm BioDyna (bio-cellulose + composite fibers), neodymium repulsion magnet circuit, 1.5 T
- Frequency response: 5 Hz – 45,000 Hz
- Impedance: 25 Ω
- Sensitivity: 100 dB/mW
- Maximum input power: 1,800 mW
- Weight: approx. 385 g (without cable)
- Housing: Japanese ornamental cherry birch + bordeaux Urushi lacquer (Sakamoto), closed chamber
- Earpads: low-resilience urethane foam + high-grade synthetic leather
- Included cable: 3 m, 7N OFC, 6.3mm plug
- Cable connector: 2-pin, rhodium-plated
- Balanced cable: XLR ET-H3.0N7BL (sold separately)
- Accessories: headphone stand, synthetic leather carrying bag
- Manufacturing: hand-assembled in Japan
