Cayin RU6 USB DAC/Amp – The audiophile USB dongle

The new Cayin RU6 USB DAC/Amp, which, as the name suggests, combines a D/A converter and headphone amplifier in the form of a USB dongle, is intended as a powerful alternative for the weak headphone output of mobile devices.

It is an almost classic combination that Cayin Audio offers with the new Cayin RU6 USB DAC/Amp, namely the function of a D/A converter in combination with a headphone amplifier, designed in the form of a USB dongle.

It is designed to drastically improve the sound quality of music playback, especially on mobile devices, while being compact enough to be taken along on the road at any time.

Cayin RU6 USB DAC/Amp – For Smartphones and Tablets

First and foremost, the new Cayin RU6 USB DAC/Amp is of course designed for smartphones and tablets, whereby it has a USB-C interface. A cable with USB-C to USB-C is included with the converter, and the manufacturer plans to offer an optional cable with USB-C to Lightning connector for devices with Apple Lightning connector such as Apple iPhone or Apple iPad.

Of course, the Cayin RU6 USB DAC/Amp can also be connected to a notebook; here, too, this solution represents a marked improvement over the audio hardware integrated in such solutions.

Signal processing up to 24 bit and 384 kHz as well as DSD256

The new Cayin RU6 USB DAC/Amp is able to process signals in Linear PCM with up to 24 bit and 384 kHz. It is also designed to play back signals in DSD, whereby audio data with up to DSD256 are supported.

Oversampling mode or NOS-DA mode

If desired, the Cayin RU6 USB DAC/Amp can perform an upsampling, whereby digital filters are used and signals are raised to 384 kHz. According to the manufacturer, this is supposed to reduce noise and improve the anti-aliasing of the signal, thus leading to a higher level of detail reproduction.

In addition to the oversampling mode, the so-called NOS-DA mode is the second option of the new Cayin RU6 USB DAC/Amp, in which the digital filters are deactivated and the signal retains its original resolution. According to the manufacturer, this mode offers the advantage that the phase distortion and the jitter remain at a very low level without artefacts in the output signal. This makes the reproduction very musical with a natural, organic and coherent sound flow.

High-precision resistor network for volume control

A special feature of the new Cayin RU6 USB DAC/Amp is that it uses a high-precision resistor array developed by Cayin Audio for volume control.

According to Cayin Audio, the best solution for the R-2R circuitry is to obtain the highest possible incoming bit-stream level and then apply high-quality analogue volume control after the signal has been converted by the R-2R DAC circuitry.

For this reason, the manufacturer recommends using a music player app that supports Bit-perfect USB, bypassing the level control of the source device, and relying instead on said high-precision resistor array volume control based on TCR25 thin-film resistors.

99 levels are available here, so that a very sensitive control can be made. It is important to know that a switching relay is used that mutes the output for a short moment to avoid clicks during level adjustment. However, this means that a small delay in the volume adjustment must be accepted.

Simple operating concept

Of course, the Cayin RU6 USB DAC/Amp has hardware buttons for volume control and a 1-inch OLED display that shows the most important information.

Unbalanced and balanced headphone connection

Headphones can be connected to the new Cayin RU6 USB DAC/Amp in two ways. Firstly, there is the unbalanced 3.5 mm stereo mini-jack, but also a balanced 4.4 mm jack, whereby 213 mW are available for headphones with an impedance of 32 ohms. The unbalanced output also provides a respectable 138 mW at an impedance of 32 ohms.

Solid, compact design

The new Cayin RU6 USB DAC/Amp is of course very compact, measuring no more than 65 mm in length, 25.4 mm in width and 13.7 mm in height. It weighs in at 28 g.

The housing is made of aluminium using CNC processing and is anodised in black. Inside, it houses a quite complex structure with two PCBs, each with six layers, whereby digital and analogue circuits are housed on separate boards.

As already mentioned, the new Cayin RU6 USB DAC/Amp is delivered with a USB-C to USB-C cable, the USB-C to Apple Lightning cable is also available as an option, as is a matching leather case, which is available in orange or blue.

The new Cayin RU6 USB DAC/Amp is available immediately from specialist retailers, with a recommended retail price of €329. The optional leather case costs € 19,90 and the USB-Lightning adapter is offered at a price of € 24,-.

Getting to the point

One could say that the new Cayin RU6 USB DAC/Amp is simply another D/A converter for mobile use with an integrated headphone amplifier, but this solution from Cayin Audio is characterised by a special feature. The manufacturer relies on a particularly precise resistor array volume control, which promises a particularly high sound quality.