Sennheiser HD 660 S Audiophile Headphones User Manual

Introduction

This manual provides instructions for the safe and efficient use of your Sennheiser HD 660 S Audiophile Open Back Headphones. Please read this manual thoroughly before using the product to ensure proper operation and to understand all features.

Sennheiser HD 660 S headphones, angled view

Image: The Sennheiser HD 660 S headphones, showcasing their open-back design and black finish.

1. Setup

1.1 Unpacking and Included Components

Carefully remove all components from the packaging. Ensure all items listed below are present.

Sennheiser HD 660 S Headphones
Connection cable with 6.35 mm stereo plug (approx. 3 meters)
Connection cable with 4.4 mm Pentaconn balanced stereo plug (approx. 3 meters)
6.35 mm to 3.5 mm adapter
User Manual (this document)

6.35mm stereo plug cable for Sennheiser HD 660 S

Image: The 6.35 mm stereo plug cable, featuring two headphone connectors and a single 6.35 mm jack.

4.4mm Pentaconn balanced stereo plug cable for Sennheiser HD 660 S

Image: The 4.4 mm Pentaconn balanced stereo plug cable, showing its two headphone connectors and the balanced Pentaconn jack.

6.35mm to 3.5mm adapter for Sennheiser HD 660 S

Image: The 6.35 mm to 3.5 mm adapter, allowing connection to smaller audio jacks.

1.2 Connecting the Headphones

Select the appropriate cable: Choose either the 6.35 mm stereo cable or the 4.4 mm Pentaconn balanced cable based on your audio source's output. If your source has a 3.5 mm jack, use the 6.35 mm cable with the provided 6.35 mm to 3.5 mm adapter.
Connect to headphones: Insert the two smaller connectors of the chosen cable firmly into the corresponding jacks on the bottom of each earcup. Ensure the 'L' (left) and 'R' (right) markings on the cable connectors match the markings on the headphone earcups.
Connect to audio source: Plug the larger end of the cable (or the adapter) into the headphone output jack of your audio device (e.g., amplifier, DAC, mobile device). The HD 660 S has a nominal impedance of 150 ohms, making it suitable for a wide range of home and mobile high-resolution audio devices.

Sennheiser HD 660 S headphones with cables connected

Image: A close-up view of the Sennheiser HD 660 S headphones with the detachable cables properly connected to the earcups.

1.3 Wearing the Headphones

Adjust the headband so that it rests comfortably on your head.
Ensure the earcups fully enclose your ears for optimal sound and comfort. The earcups are marked 'L' for left and 'R' for right.

2. Operation

2.1 Basic Audio Playback

Once connected to your audio source, begin playback from your device. Adjust the volume directly on your audio source to a comfortable listening level. The HD 660 S headphones are designed for high-fidelity audio reproduction.

Sennheiser HD 660 S headphones resting on an audio setup

Image: The HD 660 S headphones positioned next to an audio amplifier and turntable, illustrating a typical high-fidelity setup.

2.2 Important Listening Information

Volume Level: To prevent hearing damage, avoid listening at high volume levels for extended periods.
Open-Back Design: The HD 660 S features an open-back design, which provides a natural, spacious soundstage but offers minimal noise isolation. Sound will be audible to others in your vicinity.
Cable Management: The para-aramid reinforced cables are designed for durability and low handling noise. Avoid sharp bends or excessive pulling on the cables.

3. Maintenance

3.1 Cleaning the Headphones

Ear Pads and Headband: Use a soft, dry, lint-free cloth to gently wipe the ear pads and headband. Do not use cleaning agents, sprays, or solvents.
Grilles: The outer grilles can be gently brushed with a soft, dry brush to remove dust. Avoid applying pressure that could damage the internal components.
Cables: Wipe cables with a dry cloth. Ensure connectors are free of dust and debris.

3.2 Storage

When not in use, store your headphones in a clean, dry place, away from direct sunlight and extreme temperatures. Avoid placing heavy objects on the headphones.

4. Troubleshooting

Problem	Possible Cause	Solution
No sound or sound only from one side	Cable not properly connected. Audio source volume too low or muted. Incorrect cable selection for balanced/unbalanced output.	Ensure both headphone connectors and the source connector are fully inserted. Increase volume on your audio source and check if it's muted. Verify your audio source's output type (balanced/unbalanced) and use the corresponding cable.
Distorted or poor sound quality	Audio source output quality is low. Cable damage. Incorrect impedance matching (less likely with 150 Ohm).	Test with a different high-quality audio source. Inspect cables for visible damage. Try a different cable if available. Ensure your audio source can adequately drive 150 Ohm headphones.
Headphones are uncomfortable	Improper headband adjustment. New headphones, requiring break-in.	Adjust the headband for a secure yet comfortable fit. Comfort typically improves with use as ear pads conform to your head shape.

5. Technical Specifications

Feature	Detail
Model Name	HD 660 S
Brand	Sennheiser
Connectivity Technology	Wired
Ear Placement	Over Ear (Circumaural)
Impedance	150 Ohm
Frequency Response	9 Hz - 41,500 Hz
Sound Pressure Level (SPL)	104 dB (1 V)
Total Harmonic Distortion (THD)	< 0.04% (1 kHz, 100dB)
Transducer Principle	Dynamic, Open
Cable Length	3 Meters
Headphones Jack	6.35 mm Jack, 4.4 mm Pentaconn
Item Weight	9.3 ounces (approx. 264 grams)
Material	Aluminum, Metal, Plastic

6. Warranty and Support

6.1 Manufacturer's Warranty

Sennheiser products are manufactured to the highest quality standards. For detailed information regarding the warranty period and terms applicable to your HD 660 S headphones, please refer to the warranty card included in your product packaging or visit the official Sennheiser website.

6.2 Customer Support

Should you encounter any issues not covered in the troubleshooting section, or require further assistance, please contact Sennheiser customer support. You can find contact information and additional resources on the official Sennheiser website.