ElevenXIAudio Formula S


Designed for high resolution playback and ultimate bass control with the most demanding headphones.

Always on demo in the shop!


Eleven Audio TM shows the headphone 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 put the dedicated headphone amp every conneseur seeks. And it’s stout size takes up less real estate on your desktop.

Add optional PowerMan external discrete power supply for improved noise floor, low level detail retrieval, and soundstage space.


    • 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 can be ordered instead of RCA)
    • Designed with the ABYSS AB-1266 planar headphone for high resolution playback and ultimate bass control with the most demanding headphones
    • 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 external Powerman power supply upgrade


  • Input Z: 10 Kohms
  • Output: 6 watts @ 16 ohms
  • 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 (9.5″W x 11.5″D x 5.1″H)
  • Weight: 4.8 kg (10.5 lbs) (amp only)
  • 100-115VAC/230 VAC, 50/60 Hz, CE certified

Upgrade the already excellent sound of your Eleven XI Audio TM Formula S headphone amplifier with the 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 replace 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.

  • Comes with 36 cm / 14″ cable to connect to the Formula S amp
  • Dimension: 24 cm W x 26 cm D x 8.5 cm H
  • 100-115/230 VAC, 50/60 Hz (switch selectable), CE certified. (AC power cable not included. Requires an AC cable with standard 3 pin IEC connector)
  • Weight: 5 kg (11 lbs)
  • NOTE: When connecting the Powerman to the Formula S, AC power should be disconnected from both units. First, connect the supplied umbilical cable between the Formula S and Powerman and hand snug the connectors. Then connect the AC cable ONLY to the Powerman. The amp should NEVER be connected to AC power while connected to the Powerman supply else damage will occur. Only one600 AC power cord is required.