Battle of the Superdongles - Cayin RU7 vs. L&P W4

Battle of the Superdongles - Cayin RU7 vs L&P W4

There are now a myriad of audio dongles, all of which promise to turn our smartphones or laptops into audiophile machines for a reasonable price. The price range extends from well under CHF 100 to over CHF 400 and the quality is of course very different.

Today we're looking at two of the latest audio dongles coming from Cayin and Luxury & Precision: the Den Cayin RU7 and the L&P W4.

Already the two predecessors RU6 or W2-131 were two of the absolute best dongles on the market at the time - the RU6 was described by many music lovers as THE best audio dongle.

So the expectations are correspondingly high when Cayin and L&P release new dongles.

But let's have a look at the two "dongle titans" first.


What is immediately noticeable are the different designs of the dongles and the packaging. While the Cayin largely adopts the conservative design of its predecessor RU6, L&P have opted for much more eye-catching packaging and the W4 itself looks downright futuristic.


What's inside?

The scope of delivery is also different: While Cayin is giving the RU7 a free case this year in addition to the obligatory USB-C cable and USB-A adapter, L&P prefers to use an additional Lightning cable so that iPhone owners don't have to need to buy separate cable.

Cayin naturally offer an optional iPhone cable, while L&P costs extra for the protective cover. Everyone can decide for themselves what makes more sense here. In any case, the W4 case is more expensive than the iPhone cable from Cayin.
Nevertheless, I would basically be in favor of having both cable variants in the scope of delivery.

Maybe Cayin's consideration is that Apple will soon have to switch to USB-C anyway, so the tiresome topic of Lightning cables would have been settled anyway. Who knows.



Of course it's a matter of taste - but I personally like the new industrial design of the W4 much better than the conservative black box that Cayin delivers and although there is absolutely nothing wrong with the workmanship of both dongles, the W4 looks good just make me look better.

By the way, both dongles are made entirely of aluminum - Cayin's plastic/glass covers the entire top, while L&P only uses plastic/glass on the narrow display slot.

If you look at the USB-C and 3.5 & ​​44mm connections, Cayin has the edge in terms of quality: The gold-plated connections of the RU7, which are precisely integrated into the housing, are of higher quality than the W4, especially since the 3rd5mm connection, black plastic was used here for incomprehensible reasons and the USB-C connector was simply sunk into the device instead of being locked with the frame.

In view of the otherwise extremely high-quality case and significantly higher price, I find that an almost unforgivable faux pas and it just looks inconsistent! Sorry, as a designer I can't overlook something like that. 🧐


At CHF 289, the RU7 is even slightly cheaper than its predecessor and significantly cheaper than the W4, which costs CHF 459. If you want a protective cover for the W4, it costs CHF 499.00, which is CHF 210 more and is almost twice as expensive as the RU7!



While the RU7 is operated using the volume rocker and mode button, for the W4 L&P rely on a multifunction rotary control, as is already known from some cars - turning and pressing controls the volume and sound modes, whereby the Knob confirms the input with full clicks - it's really fun to use! 🤩

Of course, that doesn't mean that the RU7 is worse to use. It's just as easy, just not as cool.

In terms of dimensions and weight, both dongles are pretty much identical and are definitely not an obstacle on the go.

Design and accessories aside, I think what really counts in the end (for most audiophiles) is the sound and, as expected, both "superdongles" are excellent!

Sound & Performance

Yes both dongles deliver the best sound possible with tiny devices like this and I personally think they are the best dongles in the world right now. But where are the differences and which dongle is better suited for whom?

In terms of pure output performance, both dongles are almost identical:

4.4mm balanced: RU7 400mW | W4 420mW
3.5mm single ended: RU7 160mW | W4 110mW

This means almost doubling the output power of both dongles compared to the respective predecessor and definitely enough power for all existing IEMs and even many headphones.

Sound comparison

test devices

  • Cayin RU7
  • L&P W4
  • Unique Melody Multiverse Mentor

Both dongles basically offer a high-resolution sound with excellent details, good stage, natural voice reproduction and rich bass, to sum it up briefly.


While the W4 has a somewhat more "neutral" reference tuning and sounds a bit "brighter" and more airy than the RU7, the Cayin is as expected "warmer" and more musically tuned.

Details and resolution

You might think you can see more details due to the brighter tuning of the W4 - but if you switch to the RU7 you will find that this is not the case is. Both dongles deliver details and resolution at the same level, but simply differ in their tonality.


The voice reproduction of both dongles is very natural overall. While the RU7 tends to classify voices into the overall events, the W4 tends to put the singers in the foreground. What you prefer here is a matter of taste. I personally prefer it when the voices stand out a bit from the ensemble.


Both dongles are able to produce wonderfully airy highs without any sibilance or sibilance. Sibilance, but with decent "Sparkle". Guitar strings sound like guitar strings - that's the way it should be! While the RU7 works a bit more relaxed here, the W4 looks a bit "brighter" overall.


Due to its more neutral tuning, the W4 delivers fast, tight, well-defined bass with a focus on mid-bass rather than sub-bass.
The RU7 "rumbles" a little more in the basement: its bass reproduction is slower, more organic with a little more sub-bass than mid-bass.

Channel separation & stage

The channel separation and stage is good with both dongles, although not outstandingly good, although the RU7 sounds a bit more spacious and so that it is ahead of the curve.


It's amazing what wonderful sound is possible in this mini format! I used the Unique Melody Multiverse Mentor (MM) to evaluate both devices as the MM is a) my current favorite IEM and b ) the MM easily exposes any weakness on the part of the source.

Of course, even the best dongles in the world cannot be compared to a fully-fledged DAP (digital music player), because there are physical and monetary limits. Nevertheless, both dongles offer the best sound you can expect in connection with smartphones or PCs/laptops and even drive absolute flagships like the Multiverse Mentor without any problems.

I never had the feeling that the wonderful sound characteristics of the Mentor were being lost and that I was missing something fundamental, and that's saying something!

Which one for whom?

The question is not that easy to answer and depends on various factors, for example:

  • What sound preference someone has: Neutral/Reference = W4, Musical/Emotional/Relaxed = RU7
  • What you want to spend (The W4 is significantly more expensive with the same performance)
  • Which dongle do you like better visually?
  • . and others more

One thing is clear: You can't go wrong with either dongle, because both are absolutely excellent companions.

Both dongles are now available from Audio Essence!

Cayin RU7 - 1-bit DSD Dongle

Luxury & Precision W4 Flagship Dongle

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