ES Lab EX-1a Open-Back Electrostatic Headphone

Immerse yourself in a new tier of headphone performance with the ES Lab EX-1a — an open-back, electrostatic masterpiece designed by Hong Kong’s ES Lab. This headphone brings boutique craftsmanship, premium materials, and finely tuned electrostatic drivers into a more accessible package without compromising on soundstage or detail.

Key Features:

• Electrostatic transducer design for ultra-low distortion and natural tonality.

• Open-back architecture gives spacious, airy sound with impressive imaging and depth. 

• Compatible with 5-pin Stax type pro bias connector — ready for high-performance electrostatic amplifiers. 

• Housing crafted from aluminum-magnesium alloy for durability and premium feel.

• Excellent specification: frequency response down to 10 Hz and up to 41,000 Hz, sensitivity 99 dB/100 V, bias voltage DC 580 V. 

• Lightweight (~380 g without cable) for a high-end electrostatic design. 

Why Choose EX-1a?
ES Lab brings decades of electrostatic headphone repair and design experience to its own lineup. The EX-1a is crafted with the same attention to detail that the brand applies when servicing rare and legacy models, giving you boutique-level sound and build without the ultra-premium price tag. 

Ideal Use Case
Perfect for headphone enthusiasts with a dedicated listening space and a proper electrostatic amplifier or energizer. If you appreciate expansive soundstage, ultra-fast driver response, and high-fidelity reproduction, the EX-1a is a strong contender.

Required Compatibility
Please note: This is a true electrostatic headphone and requires a compatible energizer/amplifier capable of driving Stax-type electrostatic headphones (580 V bias, 5-pin pro bias termination). Not recommended to be used with standard headphone amplifiers or portable gear.

In the Box

• ES Lab EX-1a headphone (cable included)
  

• Warranty & product documentation

Technical Specifications:

• Transducer type: Electrostatic

• Operating principle: Open-back

• Frequency response: 10 Hz – 41,000 Hz 

• Sensitivity: 99 dB / 100 V rms 

• Bias voltage: DC 580 V 

• Weight: approx. 380 g (w/out cable) 

• Cable length: 2.3 m 

• Termination: 5-Pin Stax Type Pro Bias