Cayin RU6 Portable DAC Headphone Amplifier

Cayin RU6 Portable DAC Headphone Amplifier

Key info

• 24-Bit Discrete R-2R Resistor Ladder DAC.
• User Selectable NOS/OS Digital to Analogue Modes.
• High Precision Resistor Array Volume Control.
• Dual Main Boards Layout.
• DSD256 and PCM 384kHz.
• 3.5 mm unbalanced and 4.4 mm balanced jack output.

All specifications

Physical characteristics
Weight ~28g
Dimensions (HxWxD) 65mm X 25.4mm X 13.7mm
Frequency Response 20Hz-20kHz (±0.5dB)
Output Impedance 0.5Ω
THD+N 0.032% (1kHz, Output|0.5V)
SNR 113dB (20 Hz-20kHz, A-Weighted)
Included accessories
What's in the box USB C To C Cable (Shielded), USB A To C Adapter

Discrete 24-Bit R-2R Ladder Resistor Network Explained

The basic idea of R-2R ladder is a matched pair of two resistors, the first is R and the other is 2R which has twice the value of R.

To achieve 24bit R-2R decoding, Cayin need 48 pieces of resistors (23xR and 25x2R) for one channel, or 96 pieces of high precision resistors for stereo.

R-2R is famous for its natural and realistic sound signature, it’ll offer a very different experience to music lovers.

To achieve 24-bit R-2R decoding, Cayin searches for the resistors that can deliver extreme precision and remain stable during temperature changes.

Ultra Precision Low TCR Thin Film Resistor

  • 0.1%.
  • 1/1000.
  • Ultra High Precision.


25ppm/C Low Temperature Coefficient of Resistance

NOS or OS Dual DA Mode


  • Maintain the original sampling rate of the source bitstream.
  • Digital filter-less, no post-processing, optimised in time domain, low phase distortion and jitter, no ringing artefact.
  • Musical with vivid emotions, sounds natural, organic and coherent.


  • Increases sampling rate (upsampling) through interpolation before DA.
  • Enhances resolution, reduces noise and improves anti-aliasing, optimised in frequency domain.
  • Impressive details and frequency extension, clean and sharp presentation with darker background.

Discrete Volume Control

R-2R DAC circuit is very demanding on incoming data integrity, the digital volume of mobile phones will damage sound quality badly.

When off-the-shelf volume options cannot meet the high precision, low noise, low power consumption requirements of RU6, Cayin developed their own discrete resistor array volume control.

0-99 steps volume control through 9 segments of resistors and switching relays, meet all the RU6 requirements and transparent to maintain the natural sound signature of R-2R DAC.

Intuitive and Versatile

Hardware volume buttons for convenient control, doubled as menu selection when entering Mode settings.
1″ OLED screen displays playback information with good visibility.
3.5mm and 4.4mm phono out to fit your earphone collection.

Ultimate Dual Main Boards Layout

To minimise interference, RU6 circuitry is split into TWO 6-layers PCB, with digital and analogue circuit installed in separate boards.

Safeguard signal integrity, make sure the noise from reference clock and DSP will not bleed into the amplification circuit.

Low Power Consumption Highly Compatible

Discrete R-2R is a low-power DAC circuit when compared to other highly integrated DAC chipset on the market, minimising power drain from mobile sources.

USB Audio with shielded USB-C connector, compatible with a wide range of mobile, consumer electronics and computers.

RU6 is compatible with the following digital audio sources:

  • iOS and iPadOS.
  • macOS computers.
  • Windows 7/8/8.1/10 computers.
  • Android mobiles and tablets.
  • Digital Audio Players (Requires USB Audio Output support from the DAP).

High Resolution and High Fidelity

High-end digital audio compatibility.

  • PCM: supports up to 384kHZ.
  • DSD: supports DSD64/128/256.

Choice of High/Low gain to enhance performance with different IEM or portable friendly headphones.

Not the Smallest

Net weight around 28g only, it is small enough to slip into your smallest pocket.

Supreme and Multifunctional

Music, video, gaming… you name it, Cayin do it.


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