Cayin RU7 Review

In this article we look at the $289.99 Cayin RU7 Pure 1-Bit resistor network DAC/AMP dongle.

Disclaimer: The Cayin RU7 was sent to us free of charge by Cayin directly in exchange for this review. Cayin is in no way related to Headfonia.

Cayin

Cayin was founded in 1993 (2023 is 30th anniversary of Cayin) and it is a premium Chinese high end audio brand. Their focus has mostly been on dedicated HiFi equipment, covering every chain in the music reproduction path, from CD players to speakers, but the essence is no doubt their tube amplifiers. Their equipment ranges from around $100 to just below $10,000 per item, covering the needs of different requirements and budgets. Cayin has developed over 500 products to date, and they have received over 70 awards.

“We deliver music diligently, and we are prepared to go a long way for that.”

Lately Cayin has strongly been focusing on the portable market as well with successful units such as the N5ii, the N3Pro, the N6ii, the C9, the RU6, RU7, the reference N8/N8ii and recently the N7. If you’re still interested in finding out more about the Chinese company, then you can do so here.

The last Cayin unit we reviewed was the N7 DAP. Today we’re looking at this the newest addition to Cayin’s portable line-up, RU7 DAC/AMP dongle. The RU7 features Cayin’s 1-bit resistor network DAC technology, which we have seen before in the N7 DAP. 

Let’s find out more about the Cayin RU7!

RU7

The Cayin RU7 is the successor of the RU6 DAC/AMP, which featured the R2R technology. You can find the dedicated web page for the RU7 over here. The Cayin RU7 is selling for $289,99 USD and it’s available from Cayin’s usual distributers and dealers.

The RU7 is the second portable DAC/Amp dongle from Cayin. The reason why they got into the dongle market – according to Cayin – is because they were not satisfied with the highly integrated off-the-shelf solutions available out there. By the time Cayin completed the R01 Audio Motherboard for the N6ii DAP, they noticed that the R-2R resistor ladder network could be implemented as a low power consumption DAC circuit that offers outstanding audio performance.

Cayin has equipped the RU7 with a fully-balanced resistors network discrete 1-bit DAC for pure DSD decoding support on the go. It’s the first dongle to feature a 1-bit resistor network resistor network. The RU7 also has an All-to-DSD function upscaling your music to the DSD level. The RU7 supports PCM up to 384kHz and native DSD from DSD64 to DSD256.

The RU7 has dual-headphone outputs: a 3.5mm single-ended and a 4.4mm balanced one. With a properly designed balanced headphone amplification section, the RU7 (@32Ohm) produces a powerful output of up to 400mW on the go. In SE mode you get 160mW. The Cayin RU7 also has line-out support with fixed voltage output, allowing you to set the outputs as LO, feeding a portable or desktop amp of your choice.

The RU7 features a discrete resistor network volume control with a 100 steps volume control through 3 segments of resistors and switching relays. It offers a precise control over a wide volume range, making it ideal for sensitive IEM users. (Segment 1: 1-49, Segment 2: 50-79, Segment 3: 80-100)

RU7 Features list

• Pure 1-Bit resistor network Ladder DAC.
• Parallel Driven Balanced Amplifier Chipset.
• 3.5mm+4.4mm Dual Headphone Output.
• Supports Balanced Line-Out.
• 100-Level Resistor Array Volume Control.
• Hi-Res PCM(32-Bit/384kHz), Native DSD256 Decoding.
• All-to-DSD Function(64/128/256).
• Detachable Type-C Connector Cable.
• CNC-Machined Metallic Chassis.
• Lightweight & Ergonomic Design.
• High-Power Output(Up to 400mW, 4.4mm Bal).
• Premium Leather Case.
• 0.96” OLED Display Screen.
• Impressive Performance With Clear Dynamic Range & High SNR Performance.
• Compact & Handy.
• Works with Apple iOS, Android, Windows, and Mac devices.
• Minimum Interferences with Dual PCB. 

The full Specification overview can be found here.

1-Bit Ladder DAC

The 1-Bit ladder DAC is a purposively designed micro-miniaturized 1-bit DAC circuit from discrete components. It converts the digital signal to an analogue signal through a fully differentiate 4-ch DAC architecture. The 1-Bit DAC circuit is a resistor network composed of 128 pcs (4 x32) high precision Thin Film Resistors, and it closely resembles to the discrete DAC of Cayin’s N7 DAP.

The output of the resistor network will go through a 3-level active LPF and then converted to a single-ended signal for volume adjustment.

You can find the RU7’s full functional diagram here.

Packaging & Accessories

The Cayin RU7 comes in Cayin’s typical box as you can see in the pictures. It’s a nice box but once you take out the RY7 and its accessories, I doubt you will ever use it again.

On the inside of the box we find:

• 1 x RU7 dongle
• 1 x Type-C cable
• 1 x USB A to C adapter
• 1 x User Manual
• Protective case – handmade magnetic leather, custom made for the RU7
• 2 circular metal plates with adhesive tape pad

It’s a very nice and complete package. There’s really nothing to complain about here, it’s a nice job from Cayin, as usual.

Design, Build Quality, Lay-Out

The RU7 is a DAC/AMP dongle so there’s only so much you can do in terms of design.

The Cayin RU7 measures 66 x 24 x 12 mm and it weigh a mere 25g, making the RU7 one of the smallest dongles on the market. Small in size, but big in performance. The RU7 is simple in design but it looks stylish with the smooth curved edges, the 128 x 64 pixel OLED screen, the gold plated connectors and the sturdy, nicely clicking buttons.

On the front you find the small screen on the left with the Discrete 1-Bit DAC RU7 mention right next to it. On the left you have the USB-C input, on the right the 3.5mm and 4.4mm Line-out and outputs. On the top you find the +, – and menu button, these buttons double as screen on/off and Menu (navigation) buttons. The back of the unit has the Cayin logo and info.

The build quality is excellent and everything looks and feels sturdy. These dongle will last you a very long time, especially when you use the nice green protective case.

The review continues on the second page. Click here or use the easy jumps below.

Page 1: Cayin, RU7, Features, 1-Bit, Packaging & Accessories, Design, Build Quality, Lay-Out

Page 2: Versatility, Usability, Sound General, Sound Classics, Driveability

Page 3: Cayin RU6, Conclusion, Award, Summary