Cayin RU9 Tube/Solid-state DAC Amplifier (Like New)

Key Features

l  Nutube 6P1 Application

Supports both single-ended 3.5mm and balanced 4.4mm PO/LO outputs.

Each output can toggle between tube and solid-state modes.

l  Classic丨Modern丨SS 

Classic：

·No global negative feedback; each stage uses local feedback.

·Tube amplification introduces higher total harmonic distortion (THD).

·Rich harmonic texture delivers a warm, nostalgic sonic flavor — classic “tube sound.”

Modern：

·Introduces global negative feedback to define total gain.

·THD is significantly reduced.

·Harmonically cleaner, quieter background while preserving the warmth of tubes.

·Yields a sweet, clear, and delicate modern tube audio signature.

Solid-state：

·Based on precision-tuned op-amp ICs and peripheral circuits.

·Offers neutral tonality, fast transients, and highly accurate audio reproduction.

·Ideal for listening to music with its original, uncolored character.

l     Dual AKM AK4493SEQ DAC

Equipped with dual AK4493SEQ DACs, each operating in mono mode.

 

Left and right channels are decoded separately for lower crosstalk and better channel separation.

l  16-Core XMOS XU316 Processor

Employs the latest generation XMOS XU316 USB Audio solution for high-performance digital processing.

l     Triple Power Supply Modes

Built-in 2000mAh lithium battery provides up to 4.7 hours of battery-powered use. Also supports USB power from the external device (without charging the battery), as well as external DC power supply for increased output power.

Compatible with QC/PD fast charging.

l  Hyper Mode

A specialized feature designed for headphone usage under DC power supply. Increases static operating current and voltage for enhanced audio performance.

Balanced: 1000mW + 1000mW @ 32Ω; 1170mW + 1170mW @ 16Ω

Single-ended: 420mW + 420mW @ 32Ω; 610mW + 610mW @ 16Ω

l  Magnetic Back Design

Magnetic rear panel allows seamless attachment to smartphones.

Includes a custom Cayin leather case — hand-stitched, supple leather, precise cutouts, and magnetic back for secure attachment.

Comes with a L-shaped USB cable, ergonomically angled to avoid hand obstruction.

l  Vibration Isolation

Custom-designed anti-vibration system for the Nutube vacuum tube.

Features a custom-built silicon housing on an FPC flexible PCB and a pin-supported vertical suspension system to eliminate microphonics.

l  Elegant and Compact

CNC-machined unibody metal chassis.

Weighs only 150g, and measures 15mm thick.

l     Thoughtful Details

0.96" color display with adjustable brightness.

Knurled volume knob with refined tactile resistance.

Side-mounted multi-color indicator light for charging and sample rate/format display.

l  Versatile Use Scenarios

USB Audio DAC

Supports UAC1.0 (driverless) and UAC2.0 modes.

Compatible with smartphones, computers, digital audio players, tablets, and gaming consoles.

S/PDIF Input/Output

Uses Qualcomm QCC5125 for high-definition Bluetooth transmission.
Supports LDAC and other HD Bluetooth codecs.

Dimension (mm)：100*70*15
Weight：150g