Cayin RU7

The Cayin RU7 is the new USB DAC dongle from the Asian firm and a brand new update of the best-selling RU6. It features 4.4mm balanced output and All to DSD decoding capability up to 256.

In addition and although its size is compact, this small dongle is capable of reaching 400mW of output power per balanced output and 160mW per standard 3.5mm output.

If you want to rediscover the essence of portable audio, the RU7 is the best alternative.

The Cayin RU7 mounts a microminiaturized 1-bit DAC circuit intentionally designed from discrete components. It converts the digital signal to analog signal through a fully discrete 4-channel DAC architecture. The 1-bit DAC circuit is a resistor network that will pass through a 3-level active LPF and then convert to a single-ended signal for volume adjustment.

In its amplifier section, this RU7 features dual parallel amplifiers, which provide a 4-channel high power balanced driven output. The second amplifier is a unity-gain parallel phase inverting amplifier, resulting in unparalleled output power:

• 3.5 mm SE, 160 mW @ 32 Ohms
• 4,4 mm balanced, 400 mW at 32 Ohms

The line output voltage is carefully selected to retain the most detail and dynamics of the 1-bit DAC with the least amount of noise and distortion; this allows you to connect the RU7 to a portable/desktop amplifier or home audio system and use it as a miniature DAC.

The discrete resistance network DAC circuit is very demanding on the integrity of the incoming data, we recommend users to keep the digital volume of the cell phone at its maximum power to safeguard the quality of the digital audio signal.

When off-the-shelf analog volume options cannot meet RU7's high accuracy, low noise and low power requirements, a proprietary discrete resistor network volume control is developed.

The Cayin RU7 features 100-step volume control via 3-segment resistors and switching relays, offering precise control over a range of volume, satisfying the needs of even the most sensitive EMI users.

The RU7 supports PCM up to 384 kHz and native DSD from DSD64 to DSD256. All digital audio signal will be converted to the designated DSD format before being fed to the 1-bit discrete DAC circuitry.

To minimize interference, the internal circuitry is divided into TWO 6-layer PCBs, with digital and analog circuits installed on separate boards. This allows signal integrity to be protected, to ensure that noise from the reference clock and DSP does not enter the amplifier circuitry.

The discrete resistor network is a low power DAC circuit compared to other highly integrated DAC chipset, minimizes the power consumption of the mobile source. The redesigned amplifier circuit dramatically increases the output power while keeping the overall power consumption at 110-110 mA.

Low power consumption allows RU7 to be compatible with the following digital audio sources:

• Android based mobile devices.
  
• iOS and iPAD OS mobile devices.
  
• MacOS computers.
• Windows 7/8/8.1/10 computers.
• Digital audio players with USB audio output.

The 128x64 pixel OLED display shows playback information with good visibility. The RU7 is smaller and lighter, beveled for better handling. All surfaces are gently curved for improved look and feel.

• RU7
• Type-C Cable
• USB A-C Adapter
  
• User Manual
  
• RU7 Case