The Timeless Allure of the Koss ESP-950 Electrostatic Stereophone

Published on Dec. 19, 2023, 8:04 a.m.

The Koss ESP-950 holds a special place in headphone history as one of the early pioneers in consumer electrostatic headphone technology. First released in 1991, the ESP-950 brought the breathtaking soundstage and accuracy of an electrostatic transducer to the masses in an affordable package. Over 20 years later, it is still coveted by audiophiles as a reference headphone for classical, jazz, and acoustic recordings.


The Koss ESP-950 Electrostatic Stereophone stands out with its featherweight comfort, open-back circumaural design, and electrostatic drivers that reproduce music with unbelievable realism. Handcrafted in Milwaukee, USA, each pair reflects Koss’s commitment to quality and lifetime customer service. While the plastic build quality leaves something to be desired, the sound quality is unparalleled in its price range.

 Koss ESP-950 Electrostatic Stereophone

Design - Retro Styling

The Koss ESP-950 Electrostatic Stereophone sports a retro aesthetic with large, oval earcups hung from a lightweight plastic headband. Pivoting earcups and adjustable height ensure a custom fit. Packaged in a leather zipper case with battery pack and cables, the whole setup oozes 1970s hi-fi charm.

Sound Quality - Unrivalled Clarity

At the heart of the Koss ESP-950 Electrostatic Stereophone’s brilliance lies its electrostatic drivers. The diaphragm is an ultra-thin 1.5 micron polyester film coated with a conductive material. When powered by the dedicated E90 energizer, it achieves an incredible frequency response from 8 Hz to 35 kHz. The result is a soundstage of startling depth and width, with no listening fatigue. From the deepest bass tones to soaring treble, audio is rendered with lifelike accuracy.

Features - Engineered for Purists

Aside from the electrostatic drivers, the Koss ESP-950 Electrostatic Stereophone comes with a custom E90 energizer to power the headphones. The energizer provides 790Vrms directly to the elements for lightning transient response. Packaged with an array of cables, battery pack, and leather carrying case, the Koss ESP-950 Electrostatic Stereophone is engineered for portability and performance.

Uses - Hi-Fi Bliss

The open-back design and pinpoint accuracy of the Koss ESP-950 Electrostatic Stereophone excel at portraying the space and dimensionality of a live performance. They are especially magical with small ensemble jazz, chamber music, and vocalists. The lightweight comfort also makes them ideal for prolonged listening sessions. For discerning audiophiles seeking hi-fi bliss, the Koss ESP-950 Electrostatic Stereophone delivers an unforgettable listening experience.

Origin & History - Handcrafted in the USA

Proudly hand-assembled in Milwaukee, Wisconsin, the Koss ESP-950 Electrostatic Stereophone exemplifies American ingenuity and craftsmanship. Koss has been producing electrostatic headphones at their headquarters since the early 1960s. Each pair is individually tuned for optimal performance. With a lifetime warranty and service, they truly stand by their products.

Reception - Audiophile Favorite

The Koss ESP-950 Electrostatic Stereophone enjoys cult status among audiophiles for its reference-quality audio reproduction. Owners praise the natural tonality, silky smooth midrange, and holographic soundstage. It has become a benchmark for classical and acoustic music. While the quirks of the energizer may require troubleshooting, the lifetime warranty provides peace of mind. At its discounted price, the Koss ESP-950 Electrostatic Stereophone delivers stellar performance and enduring value.

 Koss ESP-950 Electrostatic Stereophone

Use Cases:

The Koss ESP-950 electrostatic headphones are ideal for:
- Critical listening to high-resolution music in optimal conditions
- Experiencing the intimacy of vocal performances and acoustic instruments
- Prolonged listening sessions thanks to their lightweight comfort
- Obtaining a breathtakingly realistic concert hall perspective
 Koss ESP-950 Electrostatic Stereophone

User Feedback Analysis:

Revered by audiophiles as one of the pinnacles of electrostatic headphone design, the Koss ESP-950 Electrostatic Stereophone evokes fervent admiration for its beguiling accuracy. Many deem its transient response nothing short of revelatory, catapulting listeners into a transcendent sphere.

Myriad owners extol the Koss ESP-950 Electrostatic Stereophone’s preternatural realism, as though vanishing the boundaries between recording and live performance. The expansive headstage paints sonic landscapes with holographic dimensionality, casting instruments and vocals around the listener. Treble earns consistent praise for its smooth, airy extension devoid of strident edginess. Midrange clarity likewise elicits awe, revealing microscopic nuances in timbre and texture.

Bass authority garners mixed impressions, with some wishing for visceral impact while others applaud its taut precision. Yet for certain genres like classical, jazz, and vocals, owners proclaim tonal balance that simply sounds “right.” The featherweight comfort also wins universal acclaim for all-day, fatigue-free listening.

Beyond sonics, build quality and component longevity remain points of contention. The plasticky aesthetic offends some, though functionality outweighs form for most devotees. The energizer may require troubleshooting, sending perfectionists into paroxysms yet scarcely deterring satisfaction for average listeners.

Nonetheless, flaws fade amidst overwhelming praise of the Koss ESP-950 Electrostatic Stereophone’s auditory splendor. Many deem it a priceless portal into musical truth, and some proclaim it the singular greatest headphone they’ve ever heard regardless of cost. This transcendent listening experience elevates the Koss ESP-950 Electrostatic Stereophone into rarified air, cementing its iconic status among electrostatic transducers.


  • Breathtaking realism and accuracy
  • Electrostatic speed and precision
  • Smooth, fatigue-free treble
  • Intimate midrange
  • Holographic soundstage
  • Lightweight and comfortable
  • Handcrafted in the USA


  • Bass lacks visceral impact
  • Plastic build quality
  • Energizer may require troubleshooting


For its discounted price, the Koss ESP-950 Electrostatic Stereophone delivers reference-level sound that rivals headphones costing many times more. The electrostatic drivers achieve lifelike clarity and realism unmatched in its price tier. Combined with handcrafted quality and a lifetime warranty, the Koss ESP-950 Electrostatic Stereophone is an incredible value for serious audiophiles.


The Koss ESP-950 Electrostatic Stereophone stands out as an electrostatic classic, delivering breathtaking sonic accuracy and a magical listening experience. For audiophiles searching for the holy grail of headphones, the Koss ESP-950 Electrostatic Stereophone warrants an audition to appreciate its brilliant craftsmanship and timeless allure.


  • Frequency Response: 8-35,000 Hz
  • Impedance: 100k Ohms
  • Sensitivity: 104 dB
  • Diaphragm: 1.5 micron polyester film
  • Energizer Frequency Response: 1.6 Hz – 50 kHz
  • Voltage Amplification: 60 dB
  • Audio Output Voltage: 790 Vrms
  • Signal to Noise Ratio: -100 dB

Box Contains:

  • ESP-950 Electrostatic Stereophone
  • E-90 Energizer
  • Power adapter
  • Leather carrying case
  • 3 ft RCA cable
  • 2 ft 3.5mm cable
  • 6 ft extension cable

How to Use:

  1. Connect the E90 energizer to a power source using the included power adapter.
  2. Connect your audio source to the energizer using either the RCA or 3.5mm inputs.
  3. Connect the 5-pin cable from the ESP-950 headphones to the energizer output.
  4. Adjust the left and right volume knobs on the energizer unit to balance the stereo channels.
  5. Put on the ESP-950 headphones and enjoy brilliantly realistic audio reproduction!