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US$350 is a strong deal here, sitting well below the US$350 25th percentile and far under the US$925 median for recent comparable listings. For a portable DAC/amp from a respected boutique brand, that puts it in bargain territory rather than merely “fair.”
What makes this appealing is the RU9’s niche: a compact, serious-sounding dongle-style unit with tube flavor options and enough pedigree to attract enthusiasts who want a more musical portable chain. At this price, it’s especially attractive if the unit is clean, fully working, and includes the original cable and accessories. The only things worth checking are practical ones: tube mode behavior, battery health, USB connectivity, and whether the included extras are complete.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Cayin Audio traces its roots to 1993, when Zhuhai Spark Electronic Equipment Co., Ltd. was established in Zhuhai, China. From the outset, the company focused on crafting audiophile-grade components under the Cayin brand, blending Eastern precision with a passion for musical fidelity. Over three decades, it has evolved from traditional hi-fi roots into a multifaceted player, emphasizing equipment that delivers exceptional sound across diverse price points to democratize high-quality audio.
The brand excels in a broad spectrum of categories, with its vacuum tube amplifiers standing out as flagship offerings renowned for warmth and detail. Its portfolio extends to CD players, speakers, digital audio players (DAPs), desktop systems like the i-series, portable amplifiers, in-ear monitors, and even innovative DACs such as the compact RU2 dongle. Since venturing into personal audio in 2013, Cayin has prioritized portable and lifestyle solutions, including the N-series DAPs, all while maintaining rigorous build quality with premium materials like milled aluminum and walnut wood.
Cayin holds a solid mid-to-high-end position in the global hi-fi market, prized by discerning buyers for its value-driven performance and cultural depth. It bridges accessible excellence with boutique appeal, earning acclaim for tube amps that rival pricier rivals, without veering into ultra-esoteric territory. This Chinese powerhouse continues to carve a lasting niche among knowledgeable enthusiasts seeking reliable, soulful sound.
See all Cayin Audio listings on RADAR.
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