So, I was just glossing over the product page, and looking at the specs… Is it me, or is this thing really lacking in power? Or could this possibly be a case of under specking a product, you know the “under promise, over provide”?
So mine arrived yesterday and I mounted it on the back of a dedicated iPhone source that I use with iems (blu tack 
).
First impressions after a couple of hours using it with Aune Jaspers, Dunu SA6, and UM MEST MKIIs…
Full range and impressive sound. Not a black background, clicks pops and static before the music starts and in between tracks. Not really noticeable while the music is playing. Volume can only be controlled on the RU6 itself not your source device. Slight pause/click when I turn the phone’s screen on and off.
Power? Plenty. Just tried my Sendy Aiva planars and it handled those with no problem. It will get loud enough to damage your hearing no matter what headphones you have.
Now compared to the L&P W2? The W2 is just better (subjective, non-golden ears listener). Slightly better fullness to the sound without any of the negatives. More filter and tuning options to select from and just more features in general for just a little more $.
If you’re stepping up to a “premium” dongle from a lesser one you’ll be pleased and impressed with the sound. BUT, the W2 also exists. IMHO, the W2 is still the top dog. Sure the R-2R tech in the RU6 is really cool, but the implementation of the dual CS43198 chips in the W2 is just a little bit better in my view.
My advice/initial impression? Spend a little more and get the W2.
Thanks for the info
Out of the dongles I’ve tried the W2 has been the clear winner as well, the RU6 interested me, but if it’s not really doing anything different to justify itself vs a W2 not sure if I want to pick one up or not now
Yeah, the clicks and pops bother me. I haven’t experienced that before with my gear. I’m not any good at describing sound, but I do try to do more critical listening than the average Joe.
For me, the W2 is the clear choice and I would pass on the RU6. A little disappointing as I had high expectations after jumping on the R-2R bandwagon with the HiBy RS6 DAP. I highly recommend that one! 
Hmmm that can happen with some music players or sources and not others, so perhaps try it on a few different devices and see if it still happens. It’s somewhat normal for some dacs to click and pop when they change bit depth or sample rate, but it shouldn’t happen every single track change if it’s the same format. Regardless it shouldn’t be happening in between tracks, that sounds like a player or transport problem
The rs6 looks quite interesting, although I haven’t jumped on it since I’m set with my P6 pro lol
Just a note. Cayin says to give it about 100 hours of burn-in, so there’s a chance it’ll get better… 🤷🙂
That’s true, my LP r2r daps had gotten better with more time on them, it would make sense I’d happen here (there’s also a warm up time). Also I’d imagine the device it’s connected to and the power it supplies would also make a reasonable difference in this case as well
They also mention that in the Head-Fi thread I linked…
The limit on (most) phones is 100mA I believe and 500mA on USB 2.0 and 900mA on USB 3.0.
That’s not a lot of juice and I would imagine it would lack punch perhaps?
I’m sure there’s more to it than that as well, could be loss of stage, loss of dynamics, lack of body, aforementioned punch, etc. Noticed some of those happening on other dongles I’ve tried when the device wasn’t giving it good power
Also the lack of body aspect is something I experienced when I initially got my p6 and p6 pro, which later went away after leaving it on for some days, and also making sure it warms up for 30min-hr before use
Good call, I will do that 
.
Well I will be returning the RU6 as I just can’t listen to it with its “issues.” Andrew at Musicteck will test it upon receipt to see if I just may have received a defective unit.
I hope that’s the case, as I think Cayin generally makes excellent stuff. I’ll be interested in what he says after trying it himself.
For what it’s worth he indicated that no one else has reported the problem I had. Will post his findings when I find out.
I agree with this comment:
RU6 = more realistic sound, horn speaker dynamics, less detail & refinement, far more excitement & startling factor. Faster with more air & less processed, potentially fatiguing.
W2 = less realistic, conventional speaker dynamics, more detail & refinement, far more delicacy & smooth polish. Slower with less air & more processed, easy to listen to.
Especially the very last comparison highlighted the above-mentioned findings. Ru6 is much more my style.
Hi guys, can someone share a comparison of RU6 vs Qudelix 5K or Go Blu (USB input for both)?
I’m looking for a DAC to use on the go. I’ve been using LG G8x for a while now and feel like upgrading. When it comes to function and usability, I like the idea of a wireless setup for portable use but if the RU6 sounds a lot better then I’d like to get that instead.
I’ll mostly be using IEMs so no need for a lot of power, still comparision with some other budget DAC’s like Hip-DAC, NX4… or even desktop one’s like Zen DAC, E30… are also welcome.
Finally has anyone noticed any EMI issues? I had to return my Sparrow because of that.
Disclaimer - have not heard the RU6.
AFAIK, Ru6 does not have any noticable EMI issues if any at all. At least there is no mention of it in the Head Fi thread.
RU6 should outperform the Qudelix and Go Blu quite handidly if you dig its signature which seems to be more raw.
Hopefully, that might be the case here but still, I’d like to make sure and any comments from those that have heard the device and compared it with other DACs would be nice.
It’s good to know that there are no reported EMI issues on head-fi.
I’m currently waiting on my RU6.
I’m going to be comparing it to the Ovidius B1 and also the Audioquest Dragonfly Red.
Probably not receiving it before New Years however…
Awesome, please take your time and share some impressions, I’m not in a hurry. I’m happy with my iDSD Signature’s sound for now, just need someting a bit more portable.
RU6 Review
I’ve had my RU6 for more than 2 weeks now and burn in is a must for this dongle DAC. Before the RU6 was burnt in, it sounded quite horrible in terms of technicality. The layering was mushed up together and the imaging was smeared all over the place. The tonality before burn in was quite warm. The lows was accentuated (really apparent in the low bass when compared to W2 and S1) and the mids is more forward. The upper mids and highs on the other hand was quite bad. It was incohesive and not smooth. I think this made some people to have the impression of dry sounding and in a way give the perception of detail, which I think is not the case. It was just an unrefined DAC. So let me break it down one by one after it’s been burnt in and warmed up.
Tonality
The tonality of the RU6 is quite warm. The lows is accentuated and the mids is forward, but in contrary to the brand new RU6, the burnt in RU6 has a mellow upper mids and highs. For this reason I’ll call the RU6 as a warm sounding DAC.
Soundstage, layering and imaging
The soundstage for the RU6 is always wider and larger. This might not be the most accurate representation of the music, but it’s a nice thing to have. There are times when you want a more intimate presentation, but the RU6 simply made things more distant.
In terms of layering, the RU6 gives you more layering, but it kinda suffers in terms of imaging. After the burn in, the RU6 improved a lot for this matter, but never to the point where you get a pin point imaging. For me the imaging of the RU6 is always a little bit blurred. No longer smeared, just a little bit blurred now.
If I’m going to compare it with the W2, the RU6 has a larger soundstage, but a blurred imaging, while the W2 has a smaller soundstage with a pin point imaging.
Timbre
The RU6 has a natural timbre. It plays strongly with acoustic instrument and vocals.
Transient and decay
This is where I have a problem with the RU6. The transient is soft and the decay is long, even a little bit too long. The soft transient made kick drums, snares and other sharp hitting sound to be softened. I didn’t get the same sharp definition and excitement from the RU6. The decay is also a problem. When there’s a busy and fast beat track, the long decay made everything overlaps each other. Snares sounded like it was going forever when it should’ve stopped. But at the same time, this soft transient and long decay play a large role in creating a natural timbre and large soundstage. So, I guess the RU6 is not a good DAC for electronics, rock and a like genres.
Detail retrieval
The details in the RU6 is not the greatest, especially in the highs. Most of the times I feel like there’s a veil covering the highs, which made me wanting more of the details at times. For the lows and mids, the detail retrieval is alright.
Practicality
The resistor array that’s used for the volume attenuation is both a nice thing and an annoyance. The RU6 has better dynamic and clarity at low volume level (below 15 vol), but at the same time the small clicks and delay when you are changing music or adjusting the volume is kinda annoying.
Conclusion
I think the RU6 is a really natural sounding DAC when compared to its competitors, but that’s where it ends. It plays really nicely in an orchestral, chamber, vocal and jazz music, but lags behind in electronic, rock, pop and a like music. If I didn’t know the fact that the RU6 is an R-2R DAC, I would say the RU6 is above average, but not spectacularly great DAC. I would recommend this DAC if you mainly listen to classical and acoustic music, but for electronics, pop and the others, you might want to choose other DAC.
If this will be your first dongle DAC, I wouldn’t choose this either as the RU6 is kinda specific. But if you want something different than the usual, then the RU6 is a pretty good buy.