Cayin RU3 USB Dongle

Big-stage sound, pocket-size freedom

Turn any phone or laptop into a serious hi‑fi source. Cayin RU3 brings clean, confident drive and a naturally musical tuning to your everyday listening—without the battery drain and bulk of a portable rig. If your pain points are flat dynamics, anemic bass, or hiss with sensitive IEMs, RU3 answers with 560 mW of balanced power, ultra‑low noise, and fine‑grain control over gain, filters, and EQ to match your exact gear and taste.

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Why Audiophiles Choose This Product

• Strong, engaging sound: Neutral‑to‑slightly‑warm body with tight, punchy bass, clean mids, and relaxed, non‑fatiguing treble. Reviewers praised its “clean, powerful sound from a small package.”
• Engineered for fidelity: Built around ESS’s latest HyperStream IV ES9069Q DAC with dedicated I/V (TI OPA1602 ×2) and low‑noise headphone stages (SGM8262 ×2) in a true balanced architecture for excellent channel separation and low distortion.
• Practical everywhere: Hyper/Standard power modes optimize output and heat, while 100‑step hardware volume and two gain levels make it equally comfortable with sensitive IEMs and tougher over‑ears.
• Broad, reliable compatibility: USB‑C input with UAC 2.0 for up to 32‑bit/768 kHz PCM and native DSD512; switchable to UAC 1.0 for legacy devices and gaming consoles that prefer low‑latency class‑compliant mode. Works with modern Android, macOS, and Windows systems.
• App control that matters: The Cayin Control (Android) app adds a 10‑band parametric EQ, balance, filter selection, power/gain modes, and 100‑step volume—settings are stored in the RU3 itself for use across sources.

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What’s Included

• RU3 Portable USB DAC/Headphone Amplifier: ES9069Q DAC, 3.5 mm SE and 4.4 mm balanced outputs (PO/LO shared) with color IPS display.
• USB‑C to USB‑C interconnect cable (short) for phones/tablets/laptops.
• User manual and documentation.

Note: Lightning/USB‑C adapters for older iOS devices are not included.

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Technical Specifications

Specification	Value	Notes
Product Type	Wired USB DAC/headphone amplifier (“dongle”)	USB‑C input; powered by host
DAC	ESS ES9069Q	HyperStream IV architecture for low distortion and high dynamic range
USB Audio Bridge	SPV5068 (RISC‑V dual‑core)	Stable high‑speed USB, UAC 1.0/2.0 selectable
Supported Formats	PCM up to 32‑bit/768 kHz; native DSD512	Hi‑res decoding without resampling in UAC 2.0
Outputs	3.5 mm SE; 4.4 mm balanced	PO/LO shared; line‑out selectable in menu
Output Power (32 Ω)	180 mW + 180 mW (3.5 mm); 560 mW + 560 mW (4.4 mm)	Hyper mode for maximum headroom
Gain/Power Modes	High/Low gain; Hyper/Standard power	Tailor for IEMs or full‑size headphones
THD+N	0.0018% (3.5 mm); 0.0015% (4.4 mm)	At 1 kHz with specified Vrms
SNR / Dynamic Range	115 dB (SE) / 117 dB (BAL)	20 Hz–20 kHz, A‑weighted
Frequency Response	20 Hz–50 kHz (±0.2 dB)	Extended bandwidth, flat in audible band
Output Impedance	0.7 Ω (SE); 1.2 Ω (BAL)	Preserves IEM tonal balance
Display	0.96‑inch IPS color	Real‑time sample rate, mode, volume
Filters	Multiple PCM filters (Linear/Minimum, fast/slow variants)	Adjust transient/roll‑off behavior
Dimensions	60 × 25.4 × 11 mm	Ultra‑compact footprint
Weight	24 g	Pocket‑friendly, cable‑powered

All figures per the RU3 official manual and Cayin product listing.

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Professional Recognition

• Reviews: Headfonics concludes, “The Cayin RU3… delivers competitive output power… with clean, high‑quality sound,” and highlights its app integration and drive authority at this size.
• Heritage: Cayin is the hi‑fi brand of Zhuhai Spark Electronic Equipment Co., Ltd., designing acclaimed tube amplifiers and personal audio since 1993—bringing that musical house sound to compact devices like RU3.
• Thoughtful innovation: UAC 1.0/2.0 switching for broader device support, PO/LO mode from both 3.5 mm and 4.4 mm, and Android app‑based parametric EQ are rare at this size and class.

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The Bottom Line

Cayin RU3 is the dongle to reach for when you want genuine hi‑fi dynamics and refinement from a phone or laptop, not just “good for a dongle” sound. The combination of ESS’s latest DAC, balanced architecture, robust power on the 4.4 mm output, and smart app control makes RU3 a confident daily driver for both sensitive IEMs and many full‑size headphones. If you’ve been underwhelmed by thin, bright, or underpowered dongles, RU3’s warm‑leaning neutrality, control, and headroom deliver the musical ease and authority you’ve been missing.

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Notes for setup and compatibility:

• For Windows 10/11, plug‑and‑play works; Cayin’s optional USB audio driver enables ASIO for advanced apps. macOS and modern Android are driverless. Use UAC 1.0 if a legacy device or console requires it.
• Line‑out (LO) is selectable from either jack and shares the same amplifier path—ideal for feeding powered speakers or external amps on the go.