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Delivery time approx. 1 week
The new RU9 offers exceptional features at an extremely fair price: it uses the same tubes as the "big" C9II. It also features 2 AKM DACs in mono configuration and a strong output power of up to 1000mW per channel.
The best: it is compact and lightweight, can be connected directly to a smartphone, tablet, or computer, and offers absolutely stunning sound quality!
Reviews
"The Cayin RU9 takes a legacy form factor, mixes it with modern audiophile needs to create a DAC/Amp with impressive, yet very "tweakable" sound, excellent power output, and all inside a low-profile yet extremely sturdy design.
For $499, the Cayin RU9 isn’t the cheapest option available, but in this price-range it might be one of the best solutions on the market – at the moment. Powerful, versatile, nicely built and packing real tube under the hood, it’s quintessentially Cayin, with just enough quirkiness diluted into a sea of awesomeness.
I found RU9 to be not just another dongle or a portable DAC/amp. As I mentioned earlier in the introduction of the review, this latest release from Cayin takes the concept of a “dongle” to a whole new level, making it a hybrid dongle. It is not only compact and MagSafe-ready to carry attached to your smartphone via a wired or wireless connection, but also adds NuTube into the equation with three different timbre settings to fine-tune the sound of RU9.
The Cayin RU9 represents a bold experiment in portable audio design, successfully combining vacuum tube processing, magnetic smartphone integration, wireless connectivity, and substantial amplification in a device that challenges conventional category boundaries.
Sound quality, while not reaching the heights of premium portable or desktop equipment, provides a satisfying listening experience that justifies the device’s existence. The tube processing adds genuine musical value, particularly in modern mode where technical performance remains strong while gaining harmonic richness. The amplification capability impresses across a wide range of headphones and IEMs, with the external power mode unlocking additional performance for demanding loads.
Review: Cayin RU9 Portable Tube DAC/Amp | The Headphone List
Highlights
Nutube 6P1 application
Supports both single-ended 3.5mm and balanced 4.4mm PO/LO outputs.
Each output can be switched between tube and solid-state mode.
3 sound styles: Classic丨Modern丨SS
Classic:
- No global negative feedback; each stage uses local feedback.
- The tube amplification leads to higher harmonic distortion (THD).
- The rich harmonic texture provides a warm, nostalgic sound—the classic "tube sound".
Modern:
- Introduces global negative feedback to define overall gain.
- THD is significantly reduced.
- Harmonically cleaner, quieter background while maintaining the warmth of tubes.
- Produces a sweet, clear, and delicate modern tube sound.
Semiconductor:
- Based on precisely tuned operational amplifier ICs and peripheral circuits.
- Provides neutral tonal color, fast transients, and highly accurate audio reproduction.
- Ideal for listening to music with its original, unaltered character.
Dual AKM AK4493SEQ DAC
Equipped with two AK4493SEQ DACs, each operating in mono mode. The left and right channels are decoded separately to reduce crosstalk and achieve better channel separation.
16-core XMOS XU316 processor
Uses the latest generation XMOS XU316 USB audio solution for powerful digital processing.
Triple power supply modes
The built-in 2000 mAh lithium battery allows battery use of up to 4.7 hours. Also supports power supply via USB from an external device (without charging the battery) as well as an external DC power supply for higher output power. Compatible with QC/PD fast charging.
Hyper Mode
A special function for using headphones with DC power supply. Increases the static operating current and voltage for improved audio performance.
Balanced: 1000 mW + 1000 mW at 32 Ω; 1170 mW + 1170 mW at 16 Ω
Single-ended: 420 mW + 420 mW at 32 Ω; 610 mW + 610 mW at 16 Ω
Magnetic back
- The magnetic back allows seamless attachment to smartphones.
- Included is a custom Cayin leather case – hand-stitched, made of supple leather, with precise cutouts and a magnetic back for secure hold.
- With L-shaped USB cable, ergonomically angled to avoid hindering the hand.
Vibration isolation
- Custom anti-vibration system for the Nutube vacuum tube.
- With a specially made silicone case on a flexible FPC circuit board and a vertical suspension system with pins to prevent microphonics.
Elegant and compact
- CNC-machined one-piece metal housing.
- Weighs only 150 g and is 15 mm thick.
Thoughtful details
- 0.96-inch color display with adjustable brightness.
- Knurled volume control with finely tuned resistance.
- Side-mounted multicolor indicator light for charge status and display of sample rate and format.
Diverse applications
USB audio DAC
- Supports UAC1.0 (driverless) and UAC2.0 modes.
- Compatible with smartphones, computers, digital audio players, tablets, and game consoles.
S/PDIF input/output
- Uses Qualcomm QCC5125 for high-resolution Bluetooth transmission.
- Supports LDAC and other HD Bluetooth codecs.
