Upgrading Sennheiser HD 660S2 Headphones with an iFi DAC: A Performance Review

A recent review explores the impact of adding a dedicated Digital-to-Analog Converter (DAC) to the Sennheiser HD 660S2 wired headphones. While the headphones offer exceptional sound quality and an open-backed design, the author notes that standard laptop or phone outputs often lack the power to fully drive high-impedance equipment. By integrating the iFi Zen DAC 3, which features a 390mW amplifier and support for high-resolution audio, the author sought to determine if external hardware could unlock superior sonic performance. Initial testing indicates that while the Sennheiser headphones perform impressively on their own, the addition of the iFi DAC provides noticeable improvements in vocal dynamism and overall frequency detail. The article highlights the importance of matching high-end wired audio gear with appropriate amplification to achieve the intended fidelity, confirming that a dedicated DAC is a worthwhile investment for audiophiles seeking to maximize their listening experience.