Cayin RU3 USB DAC Headphone Amplifier

The Cayin RU3 is a compact USB DAC and headphone amplifier, at 60 × 25.4mm the most compact mobile DAC/amp Cayin has made, that gives your phone, tablet or laptop a far stronger headphone output. Inside are an ESS ES9069Q DAC, a fully balanced quad-drive amplifier with up to 560mW per channel into 32Ω, and an SPV5068 RISC-V dual-core USB audio processor. It plays PCM up to 768kHz/32-bit and native DSD512 through 3.5mm and 4.4mm outputs that double as line outs, has a 0.96-inch colour screen and buttons for every setting, and weighs just 24g.

An audiophile-grade ES9069Q DAC

A single ESS ES9069Q runs in a dual-channel configuration, built on ESS’s HyperStream IV Dual DAC architecture and SABRE HiFi technology. Each channel has its own op-amp stage for precise signal processing and excellent channel separation, and a dedicated LDO power supply and an ultra-low phase-noise crystal oscillator reduce distortion and crosstalk further, for a wider, deeper soundstage and clear, layered detail.

A fully balanced quad-drive amplifier

Two Texas Instruments OPA1602 op-amps handle high-precision I/V conversion and line driving, and two SGM8262 low-noise headphone amplifiers complete a fully balanced quad-drive design. The 4.4mm balanced output gives up to 560mW + 560mW into 32Ω and the 3.5mm output 180mW + 180mW, with high and low gain to match the sensitivity and impedance of your headphones.

Hyper or Standard power

A high-efficiency power management system lets you choose how hard the RU3 works. Hyper mode gives the full output, driving a wide range of headphones with full dynamics and clarity. Standard mode reduces the power load on your phone, lowering consumption and heat for cooler, more efficient running. Cayin’s regulation circuitry keeps the sound stable in both modes.

Phone out or line out

Both the 3.5mm single-ended and 4.4mm balanced sockets can be switched between headphone output (PO) and line output (LO), so the RU3 can also feed an external amplifier.

Screen, buttons and app

The 0.96-inch IPS colour screen shows the volume, gain, EQ, output mode, UAC mode, power mode and the format and sample rate of what is playing, with a choice of UI themes. Three buttons do everything: + and − change the volume in 100 fine steps and, with a double press, skip back or forward a track, and M plays and pauses, turns the screen on and off and opens the settings menu. From there you can set the gain, one of eight PCM filters (minimum or linear phase, slow or fast roll-off), an EQ preset (Hip-hop, Classical, R&B, Dance, Rock, Pop or Jazz), PO or LO, UAC mode, power mode, brightness, screen timeout and channel balance. On Android, the Cayin Control app adds a 10-band high-precision lossless EQ for in-depth tuning and puts every setting on your phone’s screen.

UAC 2.0 and 1.0

RU3 works with Android, iOS, Windows and macOS. UAC 2.0 mode gives the full 768kHz/32-bit PCM and native DSD512 and suits most phones, tablets and computers, while UAC 1.0 mode needs no driver and connects to games consoles such as the PS5 and Nintendo Switch, and older systems. On a Mac it is plug and play; on Windows 10 and later, Cayin recommends installing its USB audio driver, which adds ASIO for better sound and lower latency.

Small, solid and colourful

The unibody chassis is CNC-milled from aerospace-grade aluminium, with an anodised finish whose dense oxide layer adds durability and a metallic texture. Choose black, purple or light cyan.

Good to know

• The RU3 is powered by the phone or computer it is connected to, and it is normal for it to get slightly warm.
• Some Android phones need OTG switched on; iPhones with a Lightning port need a USB-C to Lightning cable.
• The Cayin Control app is available for Android.
• In the box: RU3, USB-C cable and user manual.
• For more power and Bluetooth, see the Cayin RU7.