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Formula S Headphone Amplifier

by Eleven XI Audio

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When any amplifier is not good enough, powerful sound is always on tap with Eleven Audio.

A newcomer shows the world the true sound of music. Solid state dual mono amplifiers deliver stunning speed and clarity, with hard hitting bass and drums and beautifully smooth tube-like decay to cymbals and string instruments, on up beyond perception, the Formula S amp is tuned for the highest resolution music and headphones. Impeccable balance, smooth and clear to the source, excellent bass definition, simply an excellent amp. And, it's stout size takes up less real estate on your desktop.


  • Full Class A output for smooth powerful sound
  • High quality design and components throughout
  • All aluminum construction with durable beaded finish and permanent laser markings
  • Provides three of the most popular output connections for high performance headphones, 1/4" (6.3 mm), 4 pin XLR, and dual 3 pin XLR
  • High quality ALPS volume control goes from 'zero to Eleven'
  • Fully regulated power supplies
  • Output protection and turn-on/turn-off delay keeps your high end headphone investment safe.


  • Single set of RCA inputs wired direct to the volume control with JPS Labs Alumiloy® wire (no switches or extra circuit paths) (XLR inputs optional)
  • 115/230 VAC AC input selector with standard grounded IEC AC cord socket (AC cable not included, JPS Labs PAC Lite recommended)
  • Circular connector for future options (battery supply, etc)


  • Output: 6W @ 16 ohms
  • Input Z: 10 Kohms
  • Input Sensitivity: 1000 mV
  • Gain: Selectable 10 dB (Low) / 16 dB (High)
  • THD: 0.0006% @ 300 mW, distortion character compensated for high-end music playback
  • Noise floor: -110 dBV
  • Dimensions: 24 cm x 29.3 cm x 13 cm
  • Weight: 4.8 kg (10.5 lbs) (amp only)
  • 100-115VAC/230 VAC, 50/60 Hz, CE certified

OPTIONAL Eleven XI Audio Powerman Power Supply

Upgrade the already excellent sound of your Formula S headphone amplifier with this external high current power supply. Designed to sit below and mate with the Formula S, the Powerman easily connects with the supplied umbilical cable  to replaces the internal power source.

Very low noise discrete regulation and large toroidal transformer provides maximum headroom and subtle details from your Formula S amp. 

Greater soundstage depth, increased subtle details and sense of space, and very black backgrounds combine to bring the music that much closer to reality.

  • Dimension: 24 cm W x 26 cm D x 8.5 cm H
  • 100-115/230 VAC, 50/60 Hz (switch selectable), CE certified
  • Weight: 5 kg (11 lbs)

The above information is from the manufacturer.
Have a question? Connect with our Audio Gurus at 800-328-9973 or 215-862-4870 or Send email or use Contact form. You can also take advantage of our system matching expertise with a Free System Consultation.

Eleven XI Audio Formula S High Purity Headphone Amplifier - Front

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  • Eleven XI Audio Formula S High Purity Headphone Amplifier - Rear
  • Optional Powerman Power Supply


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