Join the Waitlist to be notified of launch!

Note: Pre-orders open November 6 at 8 a.m. PT. The limited first batch ships by the end of January 2027; orders allocated to the second batch are expected to ship in March 2027. All pre-orders before Jan 31, 2027 will include an extra set of earpads for alternate tuning. Allow 2–3 weeks for delivery after shipment.

A tribute to a classic electrostatic design

The ES Lab ES-HE90 is an open-back electrostatic headphone developed as a tribute to the legendary Sennheiser HE90. It combines precision-machined glass electrodes, an ultra-thin elliptical diaphragm, and bubinga wood housings with a modular construction that makes the cable, headband, and earpads replaceable by hand. 

Glass electrodes with micron-level accuracy

The ES-HE90 uses high-strength glass as the foundation for its electrostatic driver electrodes. Glass resists warping during processing, helping preserve the electrode geometry. High-precision laser cutting and chemical etching form approximately 5,000 hexagonal holes with micron-level accuracy while maintaining the substrate’s structural integrity.

Gold-coated conductive surfaces

Each glass electrode receives a sputtered chromium layer followed by a pure gold coating. These layers provide electrical conductivity and resistance to oxidation, helping maintain electrode stability over time.

Ultra-thin elliptical diaphragm

The engineering-plastic diaphragm measures approximately 0.000039 inches (1 micron) thick. ES Lab designed it to reproduce fine detail and spatial information, with an elliptical shape intended to reduce standing waves compared with a traditional circular diaphragm.

Clean-room driver assembly

ES Lab assembles the drivers entirely in a clean-room environment. After multiple cleaning procedures, a technician inspects every opening across all four electrodes for particle contamination. This attention to cleanliness helps preserve the precision of the finished driver assembly.

Bubinga wood housings

The housings use bubinga wood sourced from Africa and selected after testing different woods for their resonant characteristics. Each housing passes through multiple stages of sanding, finishing, coating, and polishing to bring out the wood’s natural grain.

Earpads that shape the tuning

Hand-assembled polyurethane foam earpads balance density, firmness, and breathability. Different earpad combinations let listeners choose a tuning intended to closely recreate the original HE90 sound signature or an alternative developed for modern recordings.

Replaceable parts for long-term ownership

The ES-HE90 weighs approximately 13.1 ounces (370 grams) without its cable. Its modular construction lets you remove and replace the earpads, headband, and cable by hand, making routine maintenance and customization straightforward.

A wooden case for storage

An included wooden case protects the headphones during storage and transport. The detachable cable measures approximately 7.5 feet (2.3 meters), providing reach between your listening chair and electrostatic amplifier.

Product highlights

• Open-back electrostatic headphones inspired by the classic HE90
  
• High-strength glass electrodes with precision-cut hexagonal openings
  
• Chromium conductive layer with a pure gold coating
  
• Ultra-thin elliptical diaphragm
  
• Bubinga wood housings
  
• Hand-assembled polyurethane foam earpads
  
• Replaceable earpads, headband, and cable
  
• 5-pin Stax-type Pro Bias termination
  
• Wooden storage case included
  
• Made in Hong Kong

Specs

• Brand: ES Lab
  
• Model: ES-HE90
  
• Transducer type: Electrostatic
  
• Acoustic design: Open-back
  
• Frequency response: 20–41,000Hz
  
• Sensitivity: 100dB at 100V RMS
  
• Bias voltage: 500–580V DC
  
• Termination: 5-pin Stax-type Pro Bias
  
• Diaphragm material: Engineering plastic
  
• Diaphragm thickness: Approximately 0.000039 inches (1 micron)
  
• Electrode substrate: High-strength glass
  
• Electrode coatings: Chromium and pure gold
  
• Housing material: Bubinga wood
  
• Earpad foam: Polyurethane
  
• Cable length: Approximately 7.5 feet (2.3 meters)
  
• Weight without cable: Approximately 13.1 ounces (370 grams)
  
• Operating temperature: 32–95°F (0–35°C)
  
• Operating humidity: 0–90%
  
• Warranty: 1 year
  
• Country of manufacture: Hong Kong

What’s included

• ES Lab ES-HE90 electrostatic headphones
  
• Detachable cable with 5-pin Stax-type Pro Bias termination
  
• Wooden storage case