Yamaha YH-1000 (1978)

These headphones feature Yamaha's exclusive Orthodynamic Design, a concept radically different from conventional dynamic or electrostatic types. Instead of an ordinary voice coil and diaphragm, it uses an ultra thin, low mass, polyester film diaphragm, sandwiched by a pair of powerful disc magnets. The voice coils are photo-etched on the surface of the diaphragm. The performance that results is marked by smooth, even response over the entire audible frequency range, low distortion, and clear imaging. The YH-1000 is a delight to wear, also: the earcups use a supra-aural design which eliminates listening fatique, and height and tilt adjustment ensure comfort over long hours of use.
"YH-1000 ia an orthodynamic headphones which has emerged as a fruition of Yamaha's unique technology of acoustic equipment development. YH-1000 is provided with a capacity of distortion-free broad band reproduction from heavy low sound to ultra high band which is characteristic of a horizontal drive system. YH-1000 also incorporates a rare earth element magnet which generates strong flux and an aluminium diecast housing which eliminates unnecessary vibrations. These features contribute to the production of powerful yet clear sound. YH-1000 is the outcome of our quest to provide comfortable feeling of fitness to your ears and ease in use, which we hope you will find satisfactory".

Specifications
Type: Orthodynamic
Diaphragm
diameter: 50 mm
Film diaphragm: 12 µm polyester
Coil diaphragm: 9 µm copper foil
Magnet: Cerium series cobalt
Frequency
response: 20 - 20,000 Hz
Sensitivity: 103 dB/1m/1W
Impedance: 100 Ω
Rated input: 3 W
Max. instant.
Input: 10 W
Total Harmonic
Distortion: 0,3% or less at 90 dB SPL
Weight: 500 g (1 lb 2 oz)