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Sennheiser HD 660s Audiophile Headphones (B-Stock) - Discontinued

Product SKU: 508826 (B)

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Product Details

↓ Details provided by Sennheiser
(Specifications and appearance of this product are subject to change without notice)

HD 660S
The perfect blend of power and control.

The powerhouse open-back headphone

Connects you to the deepest corners of your music collection.

  • Hi-fidelity sound
  • Open-back design
  • 42mm transducers
  • Luxurious comfort
  • Detachable cable

A Direct Connection To Your Music

Known for their engaging signatures and liquid-smooth response, HD 660S predecessors HD 650 and HD 600 shattered performance barriers in the audiophile headphone category.

The HD 660S transcends the best of that storied DNA with supernatural speed and effortless instrument reproduction—even at the bookends of the frequency spectrum. Utilizing an all-new transducer and specially ventilated drive unit, the HD 660S delivers the revealing, tack-sharp detail audiophiles demand without sacrificing the engaging dynamics that make music so enjoyable.

From Our Ears To Yours

In just one listen you will understand why the HD 660S is so special. Thousands of listening sessions later its purpose is even clearer.

What you hear each and every time is the result of an open-back earcup mated to a new transducer tuned for the modern audiophile. Its speedy response is perfectly suited for reproducing those frequency-stretching recordings with confidence. Thanks to an aluminum voice coil, the 38mm diaphragm remains nimble for ultra-quick impulse fidelity across the board. This activation and rest behaviour unlocks the capability to communicate tonal and spatial characteristics precisely.

Meshing Together

The steel mesh found on the HD 660S drive unit is interesting in design but most impressive when it comes to performance.

It completes the ventilated driver, offering consistent control of air displacement to reduce turbulence. As a result, diaphragm travel is pure, letting the music—and only the music—shine in a perfect balance of integrity and expression. The steel composition allows for much tighter production tolerances, ultimately contributing to remarkably consistent characteristics of each HD 660S produced. When combined with the open-back earcups, the sound emanating from each transducer is completely free to expand, just as it would in nature.

Capability, Meet Versatility.

Today’s audiophile has more component choices than ever.

We optimized the HD 660S for efficiency on a wider range of devices to accommodate the varying levels of power present in output amplification circuitry. At 150 ohms, the HD 660S is the perfect partner for dedicated amplifiers, A/V receivers, and digital audio players (DAPs)—the magnet is more powerful than its predecessors, and thus easier to drive regardless of how your setup changes over time.

Handled with care

Every HD 660S has experienced a matching regimen to mate each transducer to its opposite-channel counterpart.

These tolerances are extremely narrow and when bolstered by automated assembly processes, ensure that your HD 660S experience is consistent with those all over the globe. We designed it with thoughtful, lightweight materials invisible to the acoustical system without sacrificing the durability needed for daily, all-day use. With a never-ending supply of music to consume, we wanted every touch point to be soft, luxurious, and durable for those extended listening sessions.

It's all about connection

We packed your HD 660S with a versatile set of essential cables, each one impedance-matched with ultra-low capacitance.

The ¼-inch / 6.3mm stereo connector offers the audiophile-standard plug for connection to devices such as headphone amplifiers and A/V receivers, digital audio players, analog gear, and more. A balanced, 4.4mm connector opens a pathway to a newer generation of balanced output devices (headphone amplifiers, digital audio players, etc.) that embrace this compact plug’s superior stability over time. A balanced headphone setup offers an even lower noise floor with great dynamic range when connected to balanced source/amp circuit outputs. The listener will thus experience a wider soundstage, tightly controlled transients and impossibly-clear instrument separation. Each cable is 9.8 feet / 3m long to accommodate unencumbered listening on gear deep within your shelves, or favorite listening chair, and a flexible adapter is included to reduce the 6.3mm to 3.5mm.


  • Transducer principle dynamic, open
  • Ear coupling circumaural
  • Frequency response (speaker) 9 Hz - 41,500 Hz
  • Sound pressure level (SPL) 104 dB (1 V)
  • Total harmonic distortion (THD) < 0.04% (1 kHz, 100dB)
  • Impedance 150 Ω
  • Cable length 3 m
    • Cables
      • stereo jack plug, gold-plated 1/4" (6.35 mm), unbalanced, 3-pin
      • 4.4 mm, balanced, 5-pin
    • Adapter 6.3mm to 3.5mm
    • Magnetic field 2.5 mT
    • Weight 260 g

    Product Reviews

    Sennheiser HD 660s Audiophile Headphones (B-Stock) - Discontinued

    Customer Reviews
    5.0 Based on 3 Reviews
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    Filter Reviews:
    Jose R.
    United States United States

    B-Stock is good as new!

    Bought this because the description said this is from Sennheiser, a bit wary but when it arrived... oh my! it is good as new! the box might have little damage, but the inside everything is ok. Recommend these to everyone!

    Audio46 Sennheiser HD 660s Audiophile Headphones (B-Stock) Review
    thomas k.
    United States United States

    Sennheiser 660 S

    Another great experience

    Keith B.
    United States United States

    Sennheiser HD 660S...VR for your ears!

    I have to admit upfront, I'm new to audiophile gear. While I've tried the HE400SE, HD 560S, and SHP9600 they were all returned in favor of the HD 660S. What a great sounding set of headphones and for a great price from Audio46. Wonderful highs and lows without the shrill and ear fatique I experienced with some of the others. Although the packaging left something to be desired (blame that one on Sennheiser), the B-Stock set I received plays and looks brand new. Thanks, Audio46! I'm sure I'll be back for more.


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