HD 660S – The perfect blend of power and control, the HD 660S is a powerhouse open-back headphone with the versatility to connect you to the deepest corners of your music collection.

FEATURES

• 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.

• 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.

• 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.

• At 150 ohms, the HD 660S is the perfect partner for dedicated amplifiers, A/V receivers, and audio interfaces alike—the magnet is more powerful than its predecessors, and thus easier to drive regardless of how your setup changes over time.

• 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.

• 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, computer-based workstations, 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, studio, or desktop, and a flexible adapter is included to reduce the 6.3mm to 3.5mm. An optional balanced cable (CH 650 S) is sold separately for simplified connection to 4-pin XLR jacks.

SPECIFICATIONS

• Wearing style : Headband
• Color : matte black
• Frequency response (Headphones) : 9 – 41,500 Hz
• Sound pressure level (SPL) : 104 dB
• THD, total harmonic distortion : < 0,04%
• Contact pressure : 6.0 N ± 1 N
• Ear coupling : circumaural
• Connector : 6.35 mm / 4.4 mm Pentaconn
• Cable length : 3 m
• Transducer principle : Dynamic, open
• Nominal impedance : 150 Ω
• Weight w/o cable : 260 g