The Superdongles: Cayin RU7 and L&P W4

L&P W4

The W4 is the first L&P device I’ve had the pleasure of using, and as first impressions go, it’s nothing short of impressive. 

Aside from a few highly-regarded R2R DAPs, I know very little about this seemingly reclusive Chinese company, and it seems that only with more widespread release of its dongles (starting with the W1 In 2020) has the company started to gain mainstream acceptance in western markets. 

W4 builds on the success of the previous W-series iterations, but ups the ante not only in spec but also in build quality and industrial design. The angular gunmetal-grey, milled aluminium frame is striking, easily one of the most distinctive and visually-appealing dongles I’ve seen. 

At first sight W4 is a lot smaller than I imagined, and despite the metal build, very light too. Build quality is excellent, with seemingly super-tight tolerances, especially in the construction of the ALPS control wheel/volume dial. I really like the angled screen and neatly notched wheel, and the clever attention to detail – like being able to flip the display orientation to always align upright in use. 

W4 ships in a small, well-made blue-tinted cardboard box, with a very interesting rainbow-effect finish on its semi-gloss surface. Inside, a hard foam tray holds the W4 inside a custom cut-out, below which another tray holds the two included cables – USB-C to C and C to Lightning, with a USB-C to A adapter for plugging into legacy USB ports. 

One conspicuous absence is a protective case, which L&P sell separately to the dongle. I received the elegant, light blue leather case as part of the review, and while it’s really well-made and very good looking, I would have preferred to see it included with the dongle, especially for the $400-plus asking price. 

Some users have complained that the case doesn’t fully cover and protect the dongle, so I wouldn’t be surprised to see more robust third-party cases being made available soon. One plus of the stock case is its magnetic back, and L&P include a magnetic plate in the case box for your smart device, making it easy to piggyback the dongle to your phone. 

The ALPS wheel is the only input, acting as both as a push-button controller for menu options and display on/off, and as a wheel for settings changes and volume control. Interestingly the W4 volume steps aren’t linear, with very fine adjustments up to 50/60 on the dial, and exponentially louder adjustments towards the top end. This gives more leeway for adjusting volume with very sensitive IEMs.

There are two available outputs: 3.5mm single ended and 4.4mm balanced headphone outs. The 3.5mm output doubles as a SPIDF out too, though you’ll need a separate 3.5mm to SPDIF cable if you want to connect W4 to an external DAC. As far as I can tell there’s no dedicated line out available, so connecting W4 to an external amp will result in double-amping and at least some quality loss.  

Overall I find the design and usability of the W4 among the best I’ve experienced with any dongle. Features are plentiful, if a little basic, but more precise tweaking should be possible from the host device, depending on the music playback software you use. Look, feel and build quality are also flagship-level, as far as dongles go.  


  • DAC: custom LP5108 quad DAC
  • Volume control: ALPS potentiometer with digital relay and 100-step exponential volume curve
  • FPGA: Yes, parallel DSP processing and hardware EQ
  • SNR: 131dB (3.5mm) 134dB (4.4mm)
  • Power output (0.1% THD): 110mW (3.5mm) 420mW (4.4mm)
  • THD+N (32-ohm): 0.0003% (3.5mm) 0.00013% (4.4mm)
  • Dynamic range 134dB
  • Screen: 0.96-inch OLED
  • Audio formats (PCM): 16/24/32-bit 44.1-384KHz
  • Audio formats (DSD):  DSD64-256
  • Upgradeable firmware: Windows-only, unfortunately.
  • Dimensions: 63mm x 24mm x 12.5mm
  • Weight: 24g


  • Gain: choose between low and high gain, for sensitive to less sensitive loads.
  • EQ: choose from eight genre-based settings, including classical, jazz, rock, pop, bass, movie, game, and normal (off)
  • SDF tuning: changes tone to suit specific IEM models, including Xelento, IE800s, IE600, SE846, IER-Z1R, and normal (off)
  • Tune: choose between two tonal options, 01 (relaxed, diffuse), and 02 (lively, sharper).
  • HID Key: lets you control volume with the W4 or host device. 
  • Display flip: lets you flip the display to match your current screen orientation. 
  • UAC: supports UAC-1 and UAC-2, depending on the requirements of the host device. 
  • Filters: choose from Fast, Slow, LL Fast, LL Slow and NOS (off)

Notable features

Custom DAC. The newly-developed LP5108 chipset features a quad delta sigma DAC design for native PCM decoding. L&P claims the chipset is the reason for W4’s stellar measurements, including effectively zero distortion and zero noise floor even at high power with sensitive IEMs. It’s also claimed the new chipset is twice as power efficient as its predecessor in the W2. 

Since the DAC is based on delta sigma topology, L&P includes a dedicated DSD processor for playing native DSD files up to DSD256. This is the key difference between the DACs in the W4 and RU7.

Programmable FPGA for hardware-assisted DSP and EQ. Another interesting feature is the ‘high gate count’ FPGA chip, said to offload hardware-based DSP and EQ from the main chipset and deliver almost lossless DSP and EQ tweakability. 

Dual power supplies. W4 separates the power supplies for its analogue and digital circuits, purportedly resulting in cleaner output with negligible electrical interference from the host device.    

ALPS-based input wheel. Using hifi-grade Japanese-made ALPS Alpine components, the volume/input dial should deliver maximum precision and long-life reliability.    

Continue to W4 sound impressions…



Picture of Guy Lerner

Guy Lerner

An avid photographer and writer 'in real life', Guy's passion for music and technology created the perfect storm for his love of portable audio. When he's not playing with the latest and greatest head-fi gear, he prefers to spend time away from the hobby with his two (almost) grown kids and wife in the breathtaking city of Cape Town, and traveling around his native South Africa.


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