Hifiman via Amazon: Hifiman HE400S Over-Ear Full-Size Planar Magnetic Headphone for $129 + Free Shipping. By admin | March 9, 2020 11:57 pm EST 0 Comment Hifiman via Amazon is offering the Hifiman HE400S Over-Ear Full-Size Planar Magnetic Headphone for $129.00. Free shipping.