R U Ready For This?

Pros: Great value
Very good sound
Small and light
Works with mobile and desktop
Great battery consumption
Great build quality

Cons: No Lightning adapter included
Slightly large
Slightly expensive
Doesn’t sound as good as more expensive DAPs

Overview:

Up for review today is the Cayin RU7 1-Bit Resistor DAC/Amp USB-C Dongle – which from now on will simply be referred to as the RU7. This little guy is Cayin’s attempt at bringing the excellent Cayin N7 sound to a smaller form factor at a significantly cheaper price. The Ru7 retails for $289.99 and mine was provided to me by Musicteck (shop.musicteck.com) with a discount in exchange for a review. You can buy one here: Cayin RU7.

Build Quality / Design / Specs (20/20):

The build quality on the RU7 is excellent with CNC a milled aluminum chassis that only weighs 25g. That’s a LOT lighter than a normal DAP would be and the RU7 even comes with a tiny screen that tells you the volume and sample rate. The green leather case that comes with it is a nice touch as well (and not yellow). Of course, the main thing that the RU7 is missing is a power supply since it’s driven directly from your phone or computer. Battery and a built-in power supply/screen/all-in-one design are the obvious benefits of a DAP. So, while the RU7 manages to capture the spirit of the $2k N7 by using a 1-bit resistor ladder DAC, it could never truly capture the insane amount of performance the N7 does with far more space at 9x the cost. While some people were likely hoping for that result, and Cayin themselves directly compares the RU7 to the N7, I want to negate that idea early on in the review – these are two very different products.

What you do get is an excellent dongle that doesn’t have the issues that a lot of dongles have. You also get DSD256 and PCM 384kHz, but no MQA decoding (which may not matter soon anyway based on MQA’s bankruptcy). On top of that, there’s a resistor array volume control that works fantastically and channels the feel of a DAP’s volume control. You also get 160mW of power from the 3./5mm jack @32ohms. There is also a 4.4mm balanced output (there had better be at this price level) that provides 400mW @32 ohms. That’s a lot of power from a little dongle (that’s not really all that small compared to the HiBy FC3 – which is about 1/3rd the size if you’re looking for smol). You can also switch to line out if you want to use it as a mini-DAC, but then you end up with a silly 3-piece chain and I can’t imagine doing that with a phone – computer maybe if you really need extra amp power. There’s a lot of power and sound quality in a small, light, well-designed package – I have no reason to pull any points off here – 20/20.

Accessories (18/20):

What accessories do you expect with a USB dongle? Likely a USB-C to USB-C cable to connect to your phone – and that’s probably about it. The RU7 comes with that, and it’s a little longer than I’d like at 4” – but it’s useable and the RU7 mostly just sticks out of my pocket, making the volume controls easily accessible. However, the RU7 also comes with a USB-A to USB-C adapter included as well – likely for laptops, etc. So that’s a nice touch, although it’s missing a Lightning to USB-C converter so add an extra $10 to your purchase price if you have an iPhone as you’ll have to buy an adapter (I used this one: https://amzn.to/441d10A). The RU7 also includes that leather case though which is just awesome because if you’ve looked at a lot of dongles, you already know that almost no one includes a case with a dongle. Heck, L&P charges $33 extra for their leather case for the W4 (also available on Musicteck) – on a player that already costs $450 and provides the same output power. The W4 does come with a lightning adapter at least, so that’s…cool…

The RU7 earns 18/20 points for accessories and if it had included a Lightning adapter, it would have been the full 20 – a slight, and relatively cheap oversight on Cayin’s part.

Software / Setup / Ease of Use (20/20):

This section is going to very short as there is no setup and only 3 buttons on the player. I do want to mention though that when I plug in most dongles, Tidal pops up a message asking if I can allow the dongle. For some reason, the RU7 doesn’t have that message – it is just ready to go. All I have to do is hit play and adjust the volume. You can also go to the menu and adjust the quality to DSD 256 since it starts at 64 for some reason. There’s really nothing else to add here – it’s easy to use and the volume controls are excellent with tons of stepping and gain to really dial in your volume – an issue a lot of dongles have. 20/20 points here.

Performance / Sound (18/20):

The battery usage is excellent – I get more battery life from my Samsung Galaxy S23 Ultra using the RU7 than from the HiBy R6ProII with its large internal battery ($750 retail). I’d say that the RU7 averages around 6-7% of my phone battery an hour vs the R6PII which used almost 15% of its battery an hour. That was my biggest complaint with the R6PII (other than some weird software bugs) and the RU7 sounds trumps the R6PII in that category. The R6PII does, however, sound better than the RU7. The Cayin N7 sounds better than both, but again, we’re getting into massive levels of price difference with the R6PII costing around 2-3x as much as the RU7 and 2.5x cheaper than the N7. The RU7 sounds better than the Shanling M3U, but just slightly and that one STILL costs more. Dedicated DAPs are excellent and very hard to beat, but I would say that the RU7 gets pretty close to the excellent sound of the R6PII, while sounding slightly flatter and less full-bodied than the R6PII. It’s easily the best-sounding dongle I’ve ever heard, but that is a really low bar since most dongles just sound OK – this one at least sounds very good.

Oh, yeah, and I can power my Sennheiser HD700s and my Sendy Aivas from the 4.4mm jack at about 60/100 volume on high gain from my PC. I don’t even own a dedicated DAC or Amp anymore – it cost me about $18 for a high-definition USB-C cable (https://amzn.to/441r8TC). I ran that cable from my PC to the top of my desk and I plug in a dongle there which provides me with excellent sound quality as long as I’m not using super power-hungry headphones like the $6k Susvara (if you have a Susvara, buy a better source). Even crazier, I can power my speakers using this combo with the HiBy DAP dock. So yes, the RU7 gives me a balanced mobile and a desktop solution all in one – wicked. 18/20 points here for the excellent battery life and great sound quality.

Comparisons / Price (18/20):

I’ve covered a lot of the comparisons in other sections of this review since that’s kind of the most important part of this dongle. It has sound quality close to a $750 DAP, but without the battery issues that has, and without the dedicated platform that improves the sound quality. It’s not as small and cheap as the OK HiBy FC3 but it sounds and works significantly better. I’ve never heard the L&P W4, but the RU7 is 35% cheaper and includes a case, so more like 40% cheaper – I kind of doubt that the L&P W4 sounds 40% better (if someone wants to send me one to compare, I’ll update this section). The elephant in the room here is really the $60 Truthear SHIO (https://amzn.to/3Pd1tDj) – easily the best budget dongle out there. The SHIO doesn’t have the build quality or the OLED screen or fancy modes, etc. of the RU7, but it does have the 3.5mm and 4.4mm outputs and very good sound quality for a lot less $$$ – they’re even similar size.

This leaves the RU7 in sort of an interesting middle ground. If you just want a cheap, good dongle, the SHIO is the best cheap option. If you want better sound, a premium feel, an OLED screen, better volume control, and a 1-bit resistor DAC – the RU7 is the obvious choice. If you’re a massive L&P fan (or just love blue more than green), the 40% increase in price won’t deter you from just getting that dongle, even though the RU7 likely does everything just as well (or close) for less. If you want a separate device that doesn’t need your phone, there are a ton of small, portable options with good battery life. Where the RU7 really excels though is providing great sound quality at a reasonable price with good battery life that doesn’t require you to have a second unit in your pocket. It also gives you a really nice computer solution – you can hook this little guy up to your computer and use it as an output for music with far better quality than any soundcard is likely to give you – and it’s WAY cheaper than a full-size dedicated DAC/AMP (as long as your headphones don’t require a TON of power. 18/20 points here since the SHIO exists at 1/5th the price.

Side Note: I hated the Dragonfly Cobalt due to weird software issues where it tried to blow out my ears multiple times – this is better than that – and cheaper.

Conclusion:

My wife kidnapped my Truthear SHIO for her computer, so I have been looking for the next step up for a while and finally found it with the RU7. No, it’s not an N7 in dongle form, but at 15% the price of an N7 – it shouldn’t be. The leather case is a great touch and the sound quality and size likely can’t be beat in this price range. Also, the RU7 just works with everything I’ve plugged it into, and that in itself is worth the price of entry.

Wolfhawk’s Rating: 96/100