Massdrop x Koss ESP/95X Electrostatic System

ESP/95X Electrostatic Headphones

• Acoustic principal: Circumaural open-air design with minimal acoustic damping
• Diaphragm: Ultra-low-mass 1.5-micron C-grade polyester film coated with semiconductive material
• Diaphragm radiating surface area: 7 sq in (45.6 sq cm)
• Frequency response: 8 Hz–35 kHz
• Headband: Stainless steel, extendable
• Headband cover: Wide leatherette-style vinyl with 12mm-thick polyethylene foam padding
• Yokes: Horizontal and vertical pivoting with integral headband lock-and-detach mechanism
• Cushions: Velour-wrapped foam
• Cup size, including cushions (H x W x D): 5.9 x 3.9 x 1.6 in (15 x 10 x 4 cm)
• Cable: Straight, dual entry, 4 ft (1.2 m) with 6 ft (1.8 m) extension 
• Weight: 12.45 oz (353 g)

E/90X Electrostatic Energizer

• Frequency response: 1.6 Hz–50 kHz (-3 dB), 100 Vrms differential output
• THD + N: 0.001% at 1 kHz, 100 Vrms differential output
• Input impedance: 100 kohms
• Input level: 1 Vpk (for full power output)
• Voltage amplification: 60 dB
• Audio output voltage: 790 Vrms differential; 2,200 Vpk-pk differential with soft limiting
• Channel separation: -80 dB at 1 kHz, 100 Vrms differential output
• Signal-to-noise ratio: -100 dB at 100 Vrms output
• Bias voltage supply: 600 VDC
• Signal polarity: Absolute phase (non-inverting)
• Volume control: Dual concentric continuous audio taper high-quality potentiometer with split shaft for balance
• Switch: Power on/off rocker
• Input jacks: RCA type (left and right), 3.5mm stereo, AC/DC adapter
• Power: AC adapter power supply for E/90X (included, select 120V or 220V)
• Power consumption: 320 mA DC current at normal listening levels
• Dimensions (H x W x D): 2.6 x 4.3 x 6.1 in (6.5 x 11 x 15.5 cm)
• Weight: 17 oz (482 g)

• ESP/95X electrostatic headphones
• E/90X electrostatic energizer
• 120V or 220V AC adapter (add plug adapter for your country’s outlet)
• 3 ft (0.9 m) RCA-to-RCA cable
• 2 ft (0.6 m) 3.5mm–to-3.5mm cable
• 6 ft (1.8 m) extension cable 
• Koss's limited lifetime warranty (see warranty card)