Fostex ET-RP4.4BL 2.0 is an optional balanced cable for RP-series headphones with a single 3.5 mm earcup connector — specifically the T50RPmk4 and T60RP. It runs from a 4.4 mm TRRRS (5-pole Pentaconn) plug at the amplifier end to a single 3.5 mm TRRS plug at the headphone end. The conductor is OFC, connectors are gold-plated, the jacket is flexible PVC, and the total length is 2.0 m.
ET-RP4.4BL vs ET-RP4.4BL 2.0 — earcup connector topology
The original ET-RP4.4BL used a dedicated headphone-end termination matched to the first-generation T60RP's proprietary cup connector. The ET-RP4.4BL 2.0 updates the headphone-end to a standard 3.5 mm TRRS plug, corresponding to the single-jack connection system adopted in the T50RPmk4 and the current T60RP. This is not a Y-cable — both channels are carried through a single 4-pole 3.5 mm plug into the headphone's internal signal routing. On the amplifier side, the 4.4 mm Pentaconn carries left and right channels on fully isolated conductor pairs with no shared ground return, eliminating common-mode noise across the signal path. At the 50 Ω impedance of both the T50RPmk4 and T60RP, this directly affects channel separation and noise floor — measurable differences that matter in critical monitoring work.Practical use in studio and reference listening
The T50RPmk4 and T60RP are used for mix monitoring and mastering reference work. Balanced 4.4 mm outputs are now standard on reference-class portable and desktop DAC/amp units. The ET-RP4.4BL 2.0 allows direct connection without adapters — each adapter in the chain adds contact resistance and a mechanical failure point. At 2.0 m, the cable suits desktop amplifier positioning without excess slack.KEY FEATURES
- 4.4 mm 5-pole balanced Pentaconn (TRRRS) connector — fully balanced signal path
- Single 3.5 mm TRRS headphone connector — compatible with T50RPmk4 and T60RP
- OFC conductor — oxygen-free copper for stable signal transmission
- Gold-plated connectors at both ends — corrosion resistance and reliable electrical contact
- Flexible PVC jacket — consistent handling, no stiffness when coiled
- Length: 2.0 m (6.6 ft)
- Color: Black
TECHNICAL SPECIFICATIONS
- Model: ET-RP4.4BL 2.0
- Type: Balanced cable
- Source connector: 4.4 mm TRRRS (5-pole Pentaconn), gold-plated
- Headphone connector: 3.5 mm TRRS (4-pole), gold-plated
- Conductor: OFC (oxygen-free copper)
- Jacket: Flexible PVC
- Length: 2.0 m (6.6 ft)
- Color: Black
- Compatible models: T50RPmk4, T60RP
