Sennheiser HD 660S2 Open-Back Over-Ear Headphones｜38mm Drivers・300Ω・Audiophile-Grade Upgrade｜Parallel Import 1-Year Warranty
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International Shipping
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Macau
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Australia (6-12 business days depending on area or zone)
Free over AU$100 · Flat AU$9.99 below
United Kingdom 0-3kg (3 - 5 business days); 3kg+ (5 - 8 business days)
Free over £40 · Flat £6.99 below
Singapore (5 - 8 business days)
Free over S$40 · Flat S$9.99 below
European Union (6 - 10 business days)
Free over €49 · Flat €9.99 below
Malaysia (6 - 10 business days)
Free over RM40 · Flat RM9.99 below
🇦🇺Australia — Power Bank
| Weight | Fee |
|---|---|
| 0 – 0.51 kg | AU$ 24.39 |
| 0.51 – 1.01 kg | AU$ 36.99 |
| 1.01 – 1.51 kg | AU$ 55.99 |
🇬🇧United Kingdom — Power Bank
| Weight | Fee |
|---|---|
| 0 – 0.51 kg | £ 9.99 |
| 0.51 – 1.1 kg | £ 15.99 |
| 1.1 – 1.51 kg | £ 22.99 |
🇸🇬🇲🇾SG / Malaysia — Power Bank
| Weight | Fee |
|---|---|
| 0 – 0.51 kg | SGD 18.99 |
| 0.51 – 1.01 kg | SGD 23.99 |
| 1.01 – 1.51 kg | SGD 27.99 |
🇮🇪Ireland — Power Bank
| Weight | Fee |
|---|---|
| 0 – 0.51 kg | € 26 |
| 0.51 – 1 kg | € 39 |
| 1 – 1.51 kg | € 51.99 |
🇨🇦Canada — Power Bank
| Weight | Fee |
|---|---|
| 0 – 0.51 kg | CA$ 37.05 |
| 0.51 – 1.01 kg | CA$ 58.33 |
| 1.01 – 1.51 kg | CA$ 82.41 |
⚡ Express Shipping — free option available, refer to checkout.
📦 Heavy / Oversized items (e.g. water dispenser) — contact customer service for a custom freight quote.
Warranty
Maintenance Terms and Conditions / Warranty Information
DIGIBAL Official Warranty Coverage
This product is Authentic Hong Kong goods, enjoy Original factory one-year warranty (Unless otherwise specified on the product page). Customers must keep this information safe. Purchase receipts and products Hong Kong distributor of skin care stickers (It is recommended to take photos for record-keeping). If the product malfunctions during the warranty period, the customer must...Contact the Hong Kong general agent directly. Arrange for testing and repair.
🌏 Overseas (US / CA / UK / SG / AU)
All products are Hong Kong official versions supplied with a UK-style 3-pin plug. Travel adapters are not included. Warranty coverage ranges from 1 to 2 years, with all servicing performed in Hong Kong. Local return warehouses available in Australia, UK and USA.
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Local ReturnShipping costs are paid by the customer first.
Customer pays upfront
Ship to HK Maintenance arranged by the company
Warranty processed
Reimbursement Full refund upon presentation of receipt
Full refund of postage
Overseas customers may choose between the following two options:
For other countries, please contact customer service for a return address.
Sennheiser HD 660S2 Open-Back Over-Ear Headphones｜38mm Driver・300Ω・Audiophile Upgrade
Product Overview
This product is a parallel import (grey import) version and does not come in packaging intended for Hong Kong authorized distribution; one-year warranty is provided by our store.
Six Factual Selling Points
Three Practical Use Scenarios
Scenario 1Audiophile listening Headphone amp pairing Long listening sessions Recording reference
In the Box
Original standard retail box; actual packaging and accessories are subject to the physical product (the instruction manual language in parallel-import packaging may be English, which does not affect product functionality). If you have any questions, please contact our store before placing your order.
Why Choose This Model?
- Upgraded 38mm Driver: — New driver design enhances bass and dynamic performance.
- 8Hz–41.5kHz: — Frequency response extends to ultra-low and ultra-high frequencies.
- Open-Back Soundstage: — Open-back construction delivers a spacious, natural sense of space.
Comparison of Models in the Same Series
| Model | Type | Connection | Positioning |
|---|---|---|---|
| HD 600 | Open-back | Wired | Audiophile-grade |
| HD 650 | Open-back | Wired | Audiophile-grade |
| HD 660S | Open-back | Wired | Audiophile-grade |
| HD 660S2 | Open-back | Wired | Audiophile-grade |
| HD 620S | Closed-back | Wired | Audiophile-grade |
Learn more about models in the same series:
Comparison is limited to models available in-store; prices are subject to the price displayed on the page at the time of order.
Official Full Specifications
| Headphone Type | Open-back, over-ear |
| Driver Type | Dynamic, open-back (38 mm) |
| Frequency Response | 8 Hz – 41,500 Hz |
| Impedance | 300 Ω |
| Sensitivity (SPL) | 104 dB（1 kHz / 1 Vrms） |
| Total Harmonic Distortion (THD) | < 0.04 %（1 kHz / 100 dB） |
| Connectors | 6.3 mm plug + 4.4 mm balanced plug |
| Cable Length | 1.8 m + 1.8 m |
| Country of Origin | Ireland |
| Product Number (SKU) | 700240 |
| Package Contents | HD 660S2 headphones, 6.3mm cable (1.8m), 4.4mm balanced cable (1.8m), 6.3mm to 3.5mm adapter, portable storage pouch |
Frequently Asked Questions
Q: What is the difference between the HD 660S2 and the HD 660S?
A: The HD 660S2 is an upgraded version featuring new drivers, an extended frequency response of 8 Hz–41,500 Hz, and improved bass and dynamics.
Q: Is the 300Ω impedance difficult to drive?
A: The impedance is relatively high, so pairing it with a headphone amplifier or player is recommended for optimal performance.
Q: Is it open-back?
A: Yes. The open-back design provides a spacious soundstage, but there will be some sound leakage.
Q: Which cables are included?
A: One 6.3mm cable and one 4.4mm balanced cable.
Q: Where is it manufactured?
A: It is produced at the Sennheiser factory in Ireland.
Q: Is it suitable for direct use with a smartphone?
A: It can be driven directly, but the volume will be limited. A headphone amplifier is recommended.
Warranty
One-year warranty
1-year warranty. Warranty period is subject to the statutory requirements of the local country.（The warranty period is based on the legal requirements of the local country.）
