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Sennheiser

Sennheiser HD 660S2 Open-Back Headphones

Sennheiser HD 660S2 Open-Back Headphones

  • Authorized Retailer
  • Free US Shipping $49+
  • 1-Year Warranty
  • 45-Day Returns
$458.99 USD
$458.99 USD
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The Sennheiser HD 660S2 is an open-back audiophile headphone with 42mm transducers and a 300-ohm impedance, tuned for a natural, relaxed presentation rather than a hyped one.

Three hundred ohms is a real requirement, not a footnote — plan on a desktop amp with some voltage swing to hear the HD 660S2 properly. Open-back means it leaks both directions, so this is a quiet-room headphone: home listening, late evenings with a record, long sessions where fatigue matters more than isolation. The relaxed tuning is what makes those long sessions possible.

  • Open-back audiophile design
  • 42mm transducers, 300-ohm impedance
  • Natural, relaxed tuning for long listening sessions

Authorized Sennheiser retailer, 45-day returns, 1-year warranty.

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Frequently asked questions

Is this unit genuine?

Yes. TonePier is an authorized retailer — every unit comes from the brand or its official distributor, carries a valid serial number and is covered by the full manufacturer warranty.

How long does shipping take?

SKUs stocked in our US warehouse ship within 1–2 business days. Items shipped direct from our China hub typically arrive in 8–15 days with full tracking. The product page tells you which applies before you order.

What if it isn't for me?

You get 45 days to decide. Keep the packaging, keep it in like-new condition, and send it back for a refund. Ear tips unsealed for hygiene reasons are fine — we expect you to actually listen.