Cayin RU9 USB DAC
Cayin RU9 USB DAC
The ultimate portable tube USB DAC (amplifier): Cayin RU9
Cayin RU9
Tube magic and modern precision — pocket-sized
The Cayin RU9 features the Nutube 6P1 tube and supports both single-ended 3.5 mm and balanced 4.4 mm PO/LO outputs. This flexibility makes it easy to pair with your preferred headphones or powered speakers. A standout feature is the ability to switch between tube and solid-state operation — letting you tailor the sound to your listening preferences.
Three voicings: Classic, Modern and Solid State
- Classic: no global negative feedback, only local feedback. Higher overall THD, delivering the warm, nostalgic “tube sound”.
- Modern: global negative feedback defines overall gain. Much lower THD, cleaner background; tube warmth remains for a sweet, clear, delicate modern tube signature.
- Solid State: carefully tuned op-amp ICs and associated circuits. Neutral tonality, fast transients, and high-precision reproduction — ideal for faithful, uncolored playback.
Versatile use cases. At home, in the office, or on the go — RU9 works with smartphones, computers, digital audio players, tablets, and even gaming consoles. A strong choice for anyone looking to take their audio experience up a level.
Dual AKM DAC & 16-core XMOS processor. RU9 uses two AKM AK4493SEQ DACs in mono mode for excellent channel separation and reduced crosstalk — a clear advantage for immersive listening. A 16-core XMOS XU316 handles modern USB audio processing for high-end performance.
Modern Bluetooth & broad USB compatibility. Advanced Qualcomm QCC5125 enables high-resolution Bluetooth streaming, including LDAC and other HD codecs — great sound without cables. Thanks to UAC 1.0 (driver-free) and UAC 2.0, RU9 also offers wide device compatibility.
S/PDIF input/output. The integrated S/PDIF I/O makes it easy to connect other digital audio devices and extract the full potential of your source — for music streaming and gaming alike. RU9 delivers a clear, detailed presentation.
Compact and light. Dimensions: 100 × 70 × 15 mm • Weight: 150 g.
Your perfect companion for audiophile moments
Cayin RU9 blends classic tube tech with state-of-the-art digital processing to elevate your listening — at home or on the move. Discover RU9’s versatility and hear your music at its purest.
Technical specifications
3.5 mm PO output
| Output power (32 Ω) | 310 mW+310 mW (BAT), 420 mW+420 mW (DC) |
| Output power (16 Ω) | 440 mW+440 mW (BAT), 610 mW+610 mW (DC) |
| Frequency response | 20 Hz–32 kHz (Classic tube: 20 Hz–22 kHz) |
| THD+N (per timbre) | Solid-State ≤0.008% • Classic ≤3.0% • Modern ≤0.6% |
| Dynamic range | Up to 119 dB |
| SNR | Up to 118 dB |
| Channel separation | Up to 76 dB |
| Gain (all modes) | High 0 dB · Mid −6 dB · Low −12 dB |
| Output impedance | 0.5 Ω |
4.4 mm PO output
| Output power (32 Ω) | 620 mW+620 mW (BAT), 1000 mW+1000 mW (DC) |
| Output power (16 Ω) | 730 mW+730 mW (BAT), 1170 mW+1170 mW (DC) |
| Frequency response | 20 Hz–32 kHz (Classic tube: 20 Hz–22 kHz) |
| THD+N (per timbre) | Solid-State ≤0.008% • Classic ≤3.0% • Modern ≤0.6% |
| Dynamic range | Up to 119 dB |
| SNR | Up to 118 dB |
| Channel separation | Up to 105 dB |
| Gain (all modes) | High 0 dB · Mid −6 dB · Low −12 dB |
| Output impedance | 1.0 Ω |
Digital interfaces
| USB audio | UAC 2.0 / UAC 1.0 (switchable) |
| USB formats | PCM 16–32-bit, 44.1–768 kHz · DSD Native 64–512 · DoP 64–256 |
| Bluetooth | BT 5.1 – LDAC, aptX HD, aptX LL, aptX, AAC, SBC |
| S/PDIF in/out | 3.5 mm (shared), PCM 44.1–192 kHz |
| Compatibility | Windows (driver may be required), macOS, Android, iOS (driver-free) |
| Power / charging | Tube mode runtime approx. 3.1 hours • Charging: QC 3.0 / PD 2.0 |
