[Andykong]

Spoiler

That’s good to hear… but I have to wonder if Apple puts the same power limitations on the iPad’s USB-C as it does on an iPhone’s lightning connector. Whether or not this is a real problem with driving the RU6 with a iPhone remains conjecture as I consider it a rumor regarding reported dropouts in this forum thread, and because I cannot find any confirmation elsewhere on the web.

I figure I’d be able to judge the quality of “balanced” output by purchasing a ‘4.4mm to L&R RCA’ adapter cable, and hook the RU6 up to an auxiliary input on my Denon AVR, and then to A-B the RU6 outputs with my headphones of choice. But it still would be difficult to A-B critically, and wouldn’t make me any more comfortable with the possible power dependency problem with using with an iPhone.

You wouldn’t have an extra balanced 4.4mm cable for Shure SRH1540 headphones, would you?

4.4mm to L&R RCA? This won't prove anything because the advanage is extra headroom, but you have (1) convert 4.4mm balanced output back to single-ended (RCA), and (2) your Denon AVR has hided all the headroom and driving power advantage behinds its audio circuit.

 

[TYATYA]

I have been using the RU6 for one week now and it is by far the less "digital" sounding DAC I have ever heard.
Timbre is decidedly different from any chip based DAC and I believe it is more natural on the RU6. Dynamics and details are very good and imaging is excellent.
The only thing leaving to be desired is soundstage, though it might be more realistic than the expansive soundstage of my Audirect Atom 2.

I just have one question.
Since the OS mode upsamples everything to 384khz, when I stream Qobuz and Tidal in DSD 256 (11.2Mhz) from Audirvana, there is no difference between OS or NOS mode on the RU6. Is that right?

Tidal, qobuz and dsd?
Because RU6 is not true dsd dac (it use cpu to convert to pcm) and also two streaming is not dsd, I think no merit when you do that way.
NOS is much difference to OS: Warmer, thicker and more direct (sharp and no retouching).
OS is closer to a dac chip sound, less density for mid but more clear feeling of low and highs with darker background...
NOS and OS on ru6 does that way for whatever you input.
Pcm to dsd trick brings some benefit is when I use Onkyo HF and set 2.8Mhz High precision for saved offline tracks, with true dsd dac.
Higher SNR, separation but pay for thickness of mid (especially with 5.6Mhz conversion)

 

[Frombauge]

Thanks for the review!

Can you please comment on the hardware that is providing the RU6’s input signal and power?

Can you comment on why the balanced output is “always better than 3.5mm single ended”, especially because the RU6 balances the output via a separate amplifier on the output instead of 2 DACs up front?

The source is mainly a Samsung S21 Ultra using UAPP (with MQA add-on for those who are believers in MQA) and Tidal Masters. Have also tried a PC with Tidal Masters as the source. For music streaming using mobile phones android devices are generally speaking preferred to iOS devices. Since my initial post I have also tried the RU6 with my Focal Clears with 55 Ohm impedance. This worked perfectly fine also on my iPad Air Gen 4 with the Ru6 on high gain and volume contol at 80. Not a problem for the device, more so for my ears due to the high volume.

The comment on balanced vs. single ended comes from noise suppression, resolution and last but not least the sheer difference in output voltage and drive capability across the terminals. My use of the term balanced is related to the amplifier implementation rather than the DAC implementation (in this case R2R ladder DAC implementation) as I use a digital domain source with two channels.

Most integrated circuit audio DACs have two channels which is sufficient for stereophonic audio and can be used for balanced output in the analog domain (using my use of the term balanced). Some integrated circuit DACs have multiple channels (usually in pairs and more than one pair) which can be used for multi-channel digital sources or for two channel digital sources where the implementations using multiple DAC channels for the same digital input signal (at least theoretically) increase the SNR and channel separation in the analog domain.

Another thing worth mentioning is the superiority of resistor ladder volume controls. In my experience one should aim for this implementation also in desktop solutions.

Either way, I can really recommend the RU6 as a natural and pleasant sounding dac/amp dongle with sufficient detail and musicality satisfying most audiophiles using their ears rather than audio analyzers for making up their minds on sound quality.

 

[rarewolf]

4.4mm to L&R RCA? This won't prove anything because the advanage is extra headroom, but you have (1) convert 4.4mm balanced output back to single-ended (RCA), and (2) your Denon AVR has hided all the headroom and driving power advantage behinds its audio circuit.

Damn! Without knowing for sure, I did wonder if the AVR would handle the output to headphones differently. Thank goodness for the experts!!

You wouldn’t have an extra balanced 4.4mm cable for Shure SRH1540 headphones that I could borrow, would you?

Edit: Regarding spending $$ for the 5-10% improvement in sound with balanced being subjective… goes without saying, but if it worked it would be a long term investment. However, if it didn’t I’d be stuck with a mighty expensive 4’ dog leash. What I really need to understand is the question regarding the RU6 drawing what Apple believes is too much power. That is, I’d expect an error message before I expected dropouts…

 

[dakchi]

After almost one week and +50 hours of listening to the Cayin RU6 I’m ready to share my more detailed opinion.

Cutting to the chase, I’m now actively searching for a Cayin n6ii with R01 (or other R2R dap) and a good R2R dac for my home audio system. Guess that says something of my opinion of the Cayin RU6…

Disclaimer

As always my ears are my ears, and my impressions are my subjective impressions. I honestly find it hard to put words in ”how something sounds” and the music library and timbre preference also plays a major role in perception of a device. I’m not a true believer in “audiosciencereview”, resolution >130 dB and SNR >120 dB etc., as music ultimately is all about the feeling and enjoyment created by the music.​

General observations

• Pairing with different IEMs is of course affecting the overall perception of upstream equipment
• My assessment here has been done using the UM MEST MkII with 3.5 mm cable
• My ESS dac/amp dongles are in general a bit more detailed and analytical than the RU6
• My ESS dac/amp dongles are in general more prone to sibilance and fatigue after longer listening sessions
• For my ESS dac/amp dongles the amp implementation is coloring the sound into warmer or colder timbre (i.e. more or less shrill sounding)
• For normal listening the “brain burn-in” makes it hard to judge diminutive differences in timbre and sound quality
• I see no real life need for MQA (apologies to any still existing audiophile fan of MQA)
• I see no real life need for higher bit resolution than 24 bits (I’m more than 50 years old and my hearing is what it is in the upper trebles)
• I prefer device volume controls over UAPP (or other player) volume controls
• On an R2R dac NOS is the only filter mode I would consider as these devices are bought for their “analog sounding” characteristics
• 4.4 mm balanced is always better than 3.5 mm single ended, but again for this assessment 3.5 mm single ended was used for a like for like comparison
• On the RU6 and for this comparison I prefer the high gain setting when using the 3.5 single ended output as I perceive this to render in better dynamics (no need for the raw power on IEMs or <60 Ohm headphones)
• The RU6 is a wonderful device with a warm and cosy timbre while maintaining sufficient detail perfect for longer non-fatiguing listening sessions in a home or office environment
• I need to buy a good R2R dap as a complement to my phone and dongle setups (my eyes are currently on the Cayin n6ii Ti)
• I need to buy a good R2R dac for my larger and very stationary home audio system (my eyes are currently on the Musician Pegasus)

Comparisons

iBasso DC05 - RU6 has a warmer timbre, not as analytical but without lacking anything in terms of details and perceived resolution. I find the DC05 to have a tad better and a tad more airy treble representation bordering to sibilance, and the RU6 has far better bass/mid bass representation with full weight and warmth. For mids and vocals I find the RU6 very natural whereas the DC05 is more forward. Overall I prefer the RU6 for longer sessions due to the warm, cosy feeling that it provides.​

I would recommend the RU6 for a larger spectrum of IEMs with different timbres, whereas I would not recommend the DC05 for bright IEMs unless you are a true treble-head. Furthermore the RU6 is less sensitive to imperfect recordings. For music on the go with “darker“ IEMs the DC05 is good and inexpensive option.​

​

THX Onyx - More similar in initial timbre. I find the RU6 a bit more warm and natural sounding, and a tad less analytical. On timbre the Onyx is a bit more mid/treble forward and shines over the RU6 when doing analytical listening sessions with e.g. electrical guitar plucking, good female vocalists and electric pop with good mixing. I find the Onyx to have a bit faster bass response and slightly better punch, but for longer listening sessions I get fatigued by the more emphasized mids/treble on the Onyx.​

I would recommend both the RU6 and Onyx for a larger spectrum of IEMs with different timbres, whereas I would not recommend the the RU6 for music on the go where the Onyx is a better choice given more power (single ended) and better portability. Furthermore the RU6 is less sensitive to imperfect recordings than the Onyx.​

​

Audioquest Cobalt - RU6 every day of the year. I don’t even like the Cobalt for some reason.​

​

NextDrive Spectra X - RU6 every day of the year. The Spectra X was good when it was released, but time flies and today i find it a bit harsh sounding.​

Thank you for sharing your review. I have an Audioquest Cobalt and wondering whether RU6 would be a good upgrade for me. I do like warm holographic sound. Cobalt has very good details, but it can be sibilant sometimes. How would you describe RU6 compared to it?

 

[Frombauge]

Thank you for sharing your review. I have an Audioquest Cobalt and wondering whether RU6 would be a good upgrade for me. I do like warm holographic sound. Cobalt has very good details, but it can be sibilant sometimes. How would you describe RU6 compared to it?

The RU6 is softer, smother and less fatiguing. Without lacking detail in any shape or form, the RU6 is not as shrill as the Cobalt.

RU6 more for enjoying the music and Cobalt and other ESS-based dongles for analyzing the music. From my dongles THX Onyx is a more balanced and musical ESS-based dongle, but still not as smooth as the RU6.

RU6 is in my humble opinion a good complement to a brighter ESS-based dongle.

 

[oldkid]

Tidal, qobuz and dsd?
Because RU6 is not true dsd dac (it use cpu to convert to pcm) and also two streaming is not dsd, I think no merit when you do that way.
NOS is much difference to OS: Warmer, thicker and more direct (sharp and no retouching).
OS is closer to a dac chip sound, less density for mid but more clear feeling of low and highs with darker background...
NOS and OS on ru6 does that way for whatever you input.
Pcm to dsd trick brings some benefit is when I use Onkyo HF and set 2.8Mhz High precision for saved offline tracks, with true dsd dac.
Higher SNR, separation but pay for thickness of mid (especially with 5.6Mhz conversion)

I use Audirvana Studio on my laptop to output Qobuz and Tidal in DSD256 format, so the RU6 receive this quality as an input. I don't think the OS mode does anything in that case because DSD256 is the equivalent of 384khz PCM

 

[musicday]

Is in stock since this morning at AMP3.

 

[tonedeafmelomaniac]

Is RU6 comparable with N3Pro in terms of sound signature?

 

[Hyde00]

The RU6 is softer, smother and less fatiguing. Without lacking detail in any shape or form, the RU6 is not as shrill as the Cobalt.

RU6 more for enjoying the music and Cobalt and other ESS-based dongles for analyzing the music. From my dongles THX Onyx is a more balanced and musical ESS-based dongle, but still not as smooth as the RU6.

RU6 is in my humble opinion a good complement to a brighter ESS-based dongle.

I'm a bit torn...... I like more organic presentation for acoustic songs but I also like the aggressiveness of ESS chip for rock. I've had smooth dac/amp before and it's just not satisfying for rock.

Does RU6 still have enough "bite" for rock?

Currently using Dragonfly Red LOL.

 

[Frombauge]

I'm a bit torn...... I like more organic presentation for acoustic songs but I also like the aggressiveness of ESS chip for rock. I've had smooth dac/amp before and it's just not satisfying for rock.

Does RU6 still have enough "bite" for rock?

Currently using Dragonfly Red LOL.

When you say rock, is that classic musical rock genres or more aggressive genres like speed metal, heavy metal or similar?

For classic guitar, bass guitar, vocals centric and harmonic rock including early 70s hard rock - e.g. Tony Joe White, Nils Lofgrem, Gary Moore, Allan Taylor, Joe Bonamassa, Dire Straits, Snowy White, Gary Moore, Jeff Beck, Joe Satriani, Steve Vai, Violent Femmes, Pink Floyd, America, Deep Purple - the RU6 is really good sounding, both dynamic and technical with enough bite. Here I would say that the pairing with IEMs or low impedance headphones and their respective technicalities are more limiting than the dac/amp dongle. Nothing that I have listed to is shrill/sibilant and too much in your face with the RU6.

Have not tried speed metal, heavy metal and similar since I’m not a huge fan of those genres.

Anyway, buy and try. If not happy sell or trade. Although being on the pricey side when dac/amp dongles are concerned, It’s not like the RU6 is a multi-thousand dollar DAP, and the second hand market for an RU6 is good since an R2R is more unique than the average ”ESS or CS ” dac/amp dongle.

 

[blotmouse]

r-2r has enough "bite" for anything but the fastest of fast blast beats. Only then does it get congested. Because the music is congested.
Having a digital sharpness and filter to take away some of the note decay and reverbs on some of those recordings can help them breath, but it's not exactly true to life. It's just a more standard cheap digital presentation, kind of like throwing away detail in an mp3.

I'd choose OS mode instead of NOS for filtering to make it sound a little more like ESS. Still doesn't get the shrill right though, lol.

 

[Frombauge]

Thanks Andy for your input regarding clarifying Cayin’s implementation of “balanced output”…

I think I just wanted to hear what @Frombauge would base his “always better” statement on, and what he heard from the RU6 that justified it.

At the risk of pushing the RU6 too hard; that is, to ask it to draw too much power from the iPhone’s lighting port, I’m presently weighing the cost of a 4.4mm balanced cable against the possible benefits to what I hear from 46ohm closed-back headphones. I find myself wishing I could borrow a nearly CA$300 cable, but finding one that would work with my headphones would be rare anywhere, impossible in Newfoundland. The RU6’s 3.5mm SE output is already much better than what I had been used to. It’s torturing me to want the best out of it…

Unfortunately the problem of this hobby is that there is always something better out there. Complacency is more uncommon than OCD. We continue the chase despite full awareness of the law of diminishing returns.

Why change something at a cost if you’re happy as is? Just enjoy the music on the wonderful device that the RU6 is (irrespective of utilizing the balanced or single-ended output)!

 

[musicday]

Do I need to USB driver for Windows 10? I cannot access the official website.

 

[ssriram2791]

Do I need to USB driver for Windows 10? I cannot access the official website.

https://en.cayin.cn/down1/show?id=13630

Answer to question is "YES". The link above connects you directly to download from Cayin's website.

If that does not work, here is a google drive link below for downloading zip file

https://drive.google.com/file/d/1rLunG-9bDYljocJciucew70YqOTaXfBk/edit