• Eleven Audio at Audio46

    3 year warranty

    Eleven Audio XIAUDIO 'Formula S' High Purity Headphone Amplifier (Open Box)

    • Guaranteed to work like new or we'll exchange within 30 days. We test our Open Boxes to ensure they are in perfect operating condition. Learn more about our Open Box policy>

    Important Notice:
    • All returns on this item have a 10% restocking fee

    $3,314.00 Regular price $3,899.00 Save $585.00 (15% OFF)

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    Product SKU: XLR (OB)

    Only 1 left in stock
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    Order today for shipping on Monday.
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    between Wed, Jun 14 and Thu, Jun 15
    Order today for shipping on Monday.
    Receive FREE U.S. shipping with estimated delivery
    between Wed, Jun 14 and Thu, Jun 15

    Ⓧ Not available for shipping outside the U.S.

    General 30 Day Return/Exchange Policy with a Fee
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  • Product Details from the Brand

    Any mention of "us," "we," "our," etc is by Eleven Audio, not Audio46

    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 put the dedicated headphone amp every conneseur seeks. And it's stout size takes up less real estate on your desktop.

    Note from Joe@ABYSS:The Formula S amplifier was specifically designed for the ABYSS AB-1266 Phi CC and comes as a highly recommended mate to appreciate the headphones resolution and musical abilities. Given it's power and gain the Formula S will work it's magic on any full size high-performance headphone.

    The sonic signature of this amp can be best described as having a highly refined, detailed yet full sound with plenty of harmonic richness approaching that of a high performance tube amp without the heat. As amplifiers go, in my 30+ years in audio it's sonic signature is what everyone seeks as they spend too many years on the merry-go-round.

    Upgrade the already excellent sound of your XIAUDIO Formula S headphone amplifier by adding the Powerman external high current power supply to your order.


      • 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 inputs wired direct to the volume control with JPS Labs Alumiloy® wire, no switches or extra circuit paths. Choose XLR or RCA inputs.
      • 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 future options (battery supply, etc)


    • Input Connectors: XLR, RCA
    • Input Z: 10 Kohms
    • Output: 6W @ 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

    HIGHLY RECOMMENDED for our ABYSS AB-1266 headphone

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