Sennheiser HD 660S2 – 300 Ohm Open-Back Audiophile Headphones
Sennheiser HD 660S2 – 300 Ohm Open-Back Audiophile Headphones
- Extended Sub-Bass
- Revised 300-Ohm Transducer
- Open-Back Presentation
- Velour Contact Surfaces
- 260g Headphone Weight
- Included 6.35mm and 4.4mm Cables
- 3.5mm Adapter Included
- Made in Ireland with Replaceable Parts
In stock
AX STORE KUWAIT / AUDIO
Sennheiser HD 660S2 – 300 Ohm Open-Back Audiophile Headphones
The Sennheiser HD 660S2 is an open-back headphone for settling into a recording, with a warm presentation and extended low-frequency response. Its revised 300-ohm transducer design builds on the HD 600 family while giving the S2 its own identity.
Choose it for a quiet listening space and pair it with a suitable headphone output. Two supplied cable types make it straightforward to plan either single-ended or balanced listening without relying on an unsuitable plug adapter.
Explore the Features
FEATURE 01
Extended Sub-Bass
The S2 revision develops the lower end of the HD 660S design while retaining detail through the rest of the range. Listen to familiar acoustic bass, piano and electronic tracks to judge how the extra low-frequency extension fits your preferences.

FEATURE 02
Revised 300-Ohm Transducer
A revised voice coil, more compliant surround and optimised airflow are part of the S2 design. The 300-ohm load makes source matching worthwhile; choose an amplifier for suitable output capability, not because higher volume is the goal.
FEATURE 03
Open-Back Presentation
The open earcups suit focused home listening without sealing you off from the room. They allow sound leakage, so they are best used where nearby people or microphones will not be disturbed.

FEATURE 04
Velour Contact Surfaces
Soft velour pads and an ergonomic padded headband support comfortable listening. Position the cups evenly and take breaks during long sessions rather than using comfort as a reason to raise playback levels.
FEATURE 05
260g Headphone Weight
The listed 260g weight keeps the headphone itself manageable for a desk or listening chair. Cable routing still matters: leave slack so the lead does not pull against the fit.
FEATURE 06
Included 6.35mm and 4.4mm Cables
Two 1.8m cables let you select a single-ended 6.35mm output or a compatible balanced 4.4mm output. Use the correct complete cable for the output you choose.
FEATURE 07
3.5mm Adapter Included
The supplied 6.35mm-to-3.5mm adapter supports a conventional stereo headphone socket. Connector fit does not guarantee sufficient amplifier headroom into 300Ω.
FEATURE 08
Made in Ireland with Replaceable Parts
The HD 660S2 is made in Ireland. Detachable cables and available replacement ear cushions support ongoing maintenance of a headphone intended for repeated listening.
Plan the Headphone and Amplifier Together
The FiiO K7 and FiiO K11 provide desktop listening options with both 4.4mm balanced and 6.35mm single-ended sockets. Compare their output specifications for a 300Ω load. For a different studio workflow, the DT 900 PRO X offers a lower-impedance open-back alternative.
Frequently Asked Questions
Is this HD 660S or HD 660S2?
This is HD 660S2, manufacturer article 700240, with a 300Ω impedance and revised low-frequency response.
Does it isolate outside noise?
No. The open-back design allows sound in and out and is best suited to a quiet listening environment.
Which cables are included?
The package includes 1.8m cables with 6.35mm single-ended and 4.4mm balanced plugs, a 6.35mm-to-3.5mm adapter and a carry pouch.
Can I connect to a balanced amplifier?
Yes, using the supplied 4.4mm balanced cable and a compatible balanced headphone output. Do not adapt the single-ended cable into a balanced output.
Does HD 660S2 have Bluetooth or a microphone?
No. It is a wired headphone without a built-in microphone.
Should I use a headphone amplifier?
A suitable amplifier or DAC/amp is useful when your existing output cannot provide the listening headroom you need into 300Ω.
Why Buy from AX Store Kuwait?
Choose the exact model and connection that suit your setup at AX Store Kuwait. The specifications, setup guidance and related accessories on this page help you build a practical system around the product.
Technical Specifications
| General | |
|---|---|
| Brand | Sennheiser |
| Model | HD 660S2 |
| Type | Wired over-ear audiophile headphones |
| Acoustic Design | Open-back |
| Color | Black |
| Audio | |
| Transducer | Dynamic, 38mm |
| Impedance | 300 ohms |
| Frequency Response | 8–41,500 Hz |
| Sensitivity | 104 dB SPL at 1kHz / 1Vrms |
| THD | Less than 0.04% at 1kHz / 100 dB |
| Connection and Construction | |
| Single-Ended Cable | 6.3mm jack plug, 1.8m |
| Balanced Cable | 4.4mm balanced plug, 1.8m |
| Adapter | 6.3mm to 3.5mm |
| Cable Attachment | Detachable |
| Earpads | Velour |
| Weight | 260g |
| Country of Manufacture | Ireland |
| Built-in Microphone | No |
| In the Box | |
| Included Items | HD 660S2 headphones; 1.8m cable with 6.3mm plug; 1.8m cable with 4.4mm balanced plug; 6.3mm-to-3.5mm adapter; Carry pouch |
Recommended products
Shure SM7B
Empower Your Sound with the Legendary Shure SM7B Microphone
Shure SM7B Cardioid Dynamic Microphone
DT 990 Pro
Where Audio Fidelity Meets Unparalleled Comfort
beyerdynamic DT 990 PRO 250 Ohm open Studio Headphone
Join the best gaming community!
Join our Discord server for a community of like-minded individuals, where you can stay up to date with all the offers, new arrivals and much more.
Join the discord serverOur benefits
Secure Payments
K-NET & Credit cards
Fast shipping
Delivery in next day
Live support
Get in touch with us
Easy returns
14 days after purchase (Check Return Policy)
Subscribe to our newsletter
Subscribe to be the first to hear about our exclusive deals, special offers and upcoming products and collections.
By submitting you agree to the Terms and Conditions of our store.