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Lightly used and recently purchased.This portable DAC/amp from the highly regarded hifi company, Questyle, really sounds fantastic! The amp is great for harder to drive headphones like the ultra popular planars from Audeze, Dan Clark, Hifiman, etc.I don't have as much use for it as I expected, so here's your opportunity to get it at a solid discount.Finding a headphone DAC/amp at this level that includes analog inputs is not easy.The dual ESS9069 DAC is crystal clear and the amp circuit is clean and powerful.The digital inputs include USB C, Spdif coax, and optical.Analog inputs are 3.5mm unbalanced and 4.4mm. The 4.4mm seems to also be unbalanced based on the input level, so I recommend lowering the send to the amp by 6-9dB to allow the necessary headroom.Includes all original boxes and accessories, as well as a case.Shipping to the Continental US only.From Questyle's website:Patented Current Mode Amplifier with a fully discrete, fully balanced design delivers professional-grade performance from a portable form factor. Balances powerful drive with low power consumption, featuring a peak output power >5V and load distortion as low as 0.0002%.Equipped with dual ESS9069 DAC chips and TTA three-tier decoding architecture, breaking the limits of portable devices by offering top-tier decoding performance up to PCM768kHz and DSD512. Mobile devices can now achieve desktop-level resolution.Apple MFi certified, ensuring perfect compatibility with iPhone/iPad and seamless integration within the Apple ecosystem.Dual certified by Qualcomm Snapdragon Sound and Sony LDAC, enabling wireless enjoyment of lossless audio. 3.5mm, 4.4mm, & 6.35mm headphone output jacks, combined with manual gain control, allow easy switching to your personalized listening mode. Built-in 4300mAh high-capacity battery provides up to 12 hours of single-charge battery life. The dual USB-C port design supports charging while listening, eliminating battery anxiety.
At US$750, this sits well above the recent used market on your own data: the US$179 median and even the US$699 75th percentile, so it reads as ambitious unless the package is unusually complete or essentially mint. Compared with a typical used asking pool, that’s not a casual buy; it needs to justify itself on condition, provenance, and included extras.
That said, the SIGMA Pro is a legitimately premium portable DAC/amp, and if you want a high-end all-in-one with strong Bluetooth convenience, it has real appeal for desk and travel use. It’s the kind of piece that makes sense when an enthusiast wants top-tier portability and a cleaner-than-average used example, but at this price I’d want original accessories, battery health confidence, and proof it’s barely used.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Questyle Audio emerged in December 2012 from Shenzhen, China, founded by Jason Wong, an innovator whose university experiments in 2006 sparked the company's signature Current Mode Amplification (CMA) technology. This patented approach, filed globally just 18 months after launch, revolutionized amplifier design by adapting current amplification from high-speed communications to audio, prioritizing lossless, high-fidelity playback. Rooted in China's tech hub and manufactured by Foxconn, Questyle quickly built a global footprint through relentless R&D focused on overcoming environmental and technical barriers to pure sound.
The brand specializes in premium digital-to-analog converters (DACs), headphone amplifiers, and integrated desktop solutions, with standout portable dongles like the M12 and M15 embodying CMA alongside ESS flagship chips for PCM 384kHz/32-bit, DSD256, and MQA decoding. Their lineup emphasizes minimalist elegance, from compact mobile amps to robust desktop DAC/headphone amps like the Q192, delivering effortless, high-resolution performance without gimmicks.
Questyle holds a confident position in the high-end portable and desktop hi-fi market, earning acclaim as a premium challenger to established names through superior build, explosive detail, and V-shaped dynamics. Audiophiles praise its trouble-free excellence and technological edge, cementing its reputation among discerning buyers seeking innovative, no-compromise audio gear.
See all Questyle Audio listings on RADAR.
