Cayin, a titan in high-fidelity audio, has unveiled the RU9, a groundbreaking portable USB-DAC and headphone amplifier that brings tube-driven sound to the palm of your hand. Set to launch in mid-July 2025 at €598, the RU9 combines vintage tube warmth with cutting-edge digital precision, making it a game-changer for audiophiles on the go.
Korg Nutube 6P1 vacuum tube
Weighing just 150 grams and measuring a compact 100 x 70 x 15 mm, the RU9 is Cayin’s smallest device to incorporate the innovative Korg Nutube 6P1 vacuum tube, delivering the rich, saturated sound that hi-fi enthusiasts crave. Its CNC-milled aluminum chassis, complete with a magnetized back for easy attachment to smartphones, exudes both practicality and elegance. A knurled volume wheel and a clear display showing volume, sample rate, connection type, and battery level enhance usability, while a 2000 mAh battery offers up to 4.7 hours of playback.
Dual AK4493SEQ DAC
The RU9’s audio prowess stems from its dual AK4493SEQ DACs in a dual-mono configuration, paired with a 16-core XMOS XU316 processor, supporting high-resolution audio up to 32-bit/768kHz and DSD512. Users can toggle between three distinct sound profiles—Classic Tube for full tube warmth, Modern Tube for a cleaner, brighter tone, and Solid-State for neutral, transistor-based clarity—offering unmatched versatility for tailoring sound to personal taste or headphone pairing.
Excellent connectivity
Connectivity is a strong suit, with USB-C (UAC 1.0/2.0) for compatibility with smartphones, tablets, computers, and digital audio players, alongside Bluetooth 5.1 supporting high-definition codecs like LDAC and aptX HD. Dual headphone outputs (3.5mm single-ended and 4.4mm balanced) deliver up to 1W into 32 ohms in DC mode, ensuring ample power for demanding headphones.
Gen5 3-stage amplification architecture
Cayin’s innovative design extends to its Gen5 3-stage amplification architecture, blending tube and solid-state circuitry for dynamic, nuanced sound. Reviewers have lauded its ability to rival desktop DACs, with one calling it a “new age of dongle” for its fusion of portability and high-end performance. The magnetic housing and included L-shaped USB-C cable further enhance its practicality for mobile use.
Available from mid-July 2025 through authorized retailers like Hifonix and Cayin’s official channels, the RU9 sets a new standard for portable audio, proving that true hi-fi sound can travel anywhere. For audiophiles seeking uncompromising quality in a compact package, the Cayin RU9 is a must-have.
