Cayin RU6: R-2R USB Dongle DAC with Head-Amp

[Andykong]

I don't think people are buying the RU6 to use with amplifiers... but for owners of the RU6, because we like it so much, we are finding ways to use it in our other chains. And despite not having a proper LO, it's surprisingly good. I've successfully used it at 100 volume with no discernible distortion using my headphones and IEMs. But of course YMMV.

If I'm going out with my laptop in tow, I find myself reaching for the RU6 and my WA8 to bring along (often just the RU6), rather than a DAP. I almost never use it with my phone. The RU6 is one of the most versatile piece of audio equipment in my tiny arsenal. Strangely I did not feel the same with the W2 hmmm

You'll be surprised, I received numerous inquiries about whether they should purchase the RU6 as an entry-level R-2R DAC for their home audio system.

The noise and distortion issue is related to the gain ratio of the amplifier and the sensitivity of the IEM downstream. As an end=user, you only need to be concerned about whether it might or might not appear in your system. To me, I need to worry if it will affect 1 out of 100 combinations.

 

[peterinvan]

Having said that, I still hold the point that RU6 is not an ideal line-out source. If you have an amplifier lying around, no harm to give it a try. However, I don't recommend something to buy a new amplifier and using the RU6 as the DAC of a larger system.

I am using my RU6 (3.5mm out) to drive my living room stereo amp (Onkyo A-9110).
I find it provides a high quality source with no distortion etc. Volume is controlled on both the RU6 and the Onkyo.

Tidal is running on my iPad Pro, with USB-C out. It is set at minimal volume. The volume setting on the iPad makes no difference to the RU6 so long as it is not set to mute.

 

[Johnfg465vd]

Out of curiosity, what benefits would there be in using Balanced Out on RU6 into an external Amp vs using 3.5 Out on RU6?

The only thing I could think of was improved headroom. Ex. with Gryphon, I'm at ~80/106 to get adequate volume with Sundara. If I pair RU6 (85 Volume) & Gryphon with 3.5 to 3.5 Interconnect, I have to push the volume to 100+ to get a good enough volume level. I'm guessing using a 4.4 to 4.4 Interconnect would mean I get more voltage and so less need to push the Amp harder? any other benefits?

Also, has anyone tried using USB purifiers (AudioQuest Jitterbug, iFi iSilender+...) with RU6?

 

[peterinvan]

Out of curiosity, what benefits would there be in using Balanced Out on RU6 into an external Amp vs using 3.5 Out on RU6?

The only thing I could think of was improved headroom. Ex. with Gryphon, I'm at ~80/106 to get adequate volume with Sundara. If I pair RU6 (85 Volume) & Gryphon with 3.5 to 3.5 Interconnect, I have to push the volume to 100+ to get a good enough volume level. I'm guessing using a 4.4 to 4.4 Interconnect would mean I get more voltage and so less need to push the Amp harder? any other benefits?

Also, has anyone tried using USB purifiers (AudioQuest Jitterbug, iFi iSilender+...) with RU6?

I would be careful with balanced-out unless you have balanced-in on the amp. Shorting the left and right common to ground may damage the RU6 (or any balanced source).
I run the RU6 at 50% high gain, and the Onkyo at 50% volume. Plenty loud.

I have the Ifi silencer and a Jitterbug, but I see no reason to put something else in the data path, since my iPad Pro is a clean noise free source.

As far as headphones, I can drive my LCD-XC directly from the RU6 with plenty of headroom. Sounds great.

 

[emilsoft]

my hope was that the RU6 could keep up with the other DAPs and deliver a similarly good sound due to the hardware savings such as processor, screen, battery etc. then I will get the HiBy RS6 and compare. could you tell me what sound I get compared to the RU6

The RS6 is a desktop R2R dac replacement IMO. It has a bold muscular sound with focus on mids, lower mids and bass. It sounds unrestrained and very open and direct. It opens up my speakers so much so that they disappear from the room leaving only holographic musicians in front. It can make some IEMs sound like full open back headphones.. you get where I'm going with this - i.e. the RS6 is worth its flagship asking price. The RU6 punches above it's weight in the price range (simply because there are no other R2R dongles), but it is not as massive, unrestrained and bold sounding as the RS6. When a wall of sound hits you from the RS6 you'll know what I mean.

but - the Hiby absolutely needs its 200 hours of burn in. Before that it can change it's signature (sometimes in a weird way) until it settles.

 

[TYATYA]

Out of curiosity, what benefits would there be in using Balanced Out on RU6 into an external Amp vs using 3.5 Out on RU6?

The only thing I could think of was improved headroom. Ex. with Gryphon, I'm at ~80/106 to get adequate volume with Sundara. If I pair RU6 (85 Volume) & Gryphon with 3.5 to 3.5 Interconnect, I have to push the volume to 100+ to get a good enough volume level. I'm guessing using a 4.4 to 4.4 Interconnect would mean I get more voltage and so less need to push the Amp harder? any other benefits?

Also, has anyone tried using USB purifiers (AudioQuest Jitterbug, iFi iSilender+...) with RU6?

Except higher output SPL, I mostly do not find improvement when I feed RU6 to 2 headamp (one electrodynamic, one e.stat).
There a very littleeeee as placebo effect or real I am not so sure: 4.4 is more dynamic and 3.5 is fuller.

When ru6 drives hd800s I found volume lvl 90 and 91 has difference: lvl91 sound not smooth as 90 and 91 feel dry sound (or some one may feel distortion). But if feed to a amp, I run ru6 at vol 100%

 

[emilsoft]

Out of curiosity, what benefits would there be in using Balanced Out on RU6 into an external Amp vs using 3.5 Out on RU6?

The only thing I could think of was improved headroom. Ex. with Gryphon, I'm at ~80/106 to get adequate volume with Sundara. If I pair RU6 (85 Volume) & Gryphon with 3.5 to 3.5 Interconnect, I have to push the volume to 100+ to get a good enough volume level. I'm guessing using a 4.4 to 4.4 Interconnect would mean I get more voltage and so less need to push the Amp harder? any other benefits?

Also, has anyone tried using USB purifiers (AudioQuest Jitterbug, iFi iSilender+...) with RU6?

Aside from the significantly increase power output, I find balanced out a little broader, more weighty and somewhat smoother sounding vs the 3.5mm - this is even with very sensitive IEMs. Maybe it's due to output impedance interaction with balanced armatures or what have you I'm not sure, but I prefer it.

I also use the ifi micro iusb 3.0 usb decrapifier and clean power supply and it makes the RU6 whisper sweet nothings in my ears. In general the imicro makes everything sound better so this is expected. What is interesting though is that the RU6 still sounds very good out of a computer directly and doesn't cry out for a decrapifier like many other delta sigma dacs where it's almost a necessity

 

[Andykong]

Out of curiosity, what benefits would there be in using Balanced Out on RU6 into an external Amp vs using 3.5 Out on RU6?

The only thing I could think of was improved headroom. Ex. with Gryphon, I'm at ~80/106 to get adequate volume with Sundara. If I pair RU6 (85 Volume) & Gryphon with 3.5 to 3.5 Interconnect, I have to push the volume to 100+ to get a good enough volume level. I'm guessing using a 4.4 to 4.4 Interconnect would mean I get more voltage and so less need to push the Amp harder? any other benefits?

Also, has anyone tried using USB purifiers (AudioQuest Jitterbug, iFi iSilender+...) with RU6?

If you are connecting the RU6 to an external Amp, I'll suggest you stay with the Single-ended connection. I have shared my observation previously.

The 4.4mm phone output of RU6 is balanced driven, but the signal path is primarily a single-ended design. We added an extra op-amp (identical to the primary headphone amplification Op-Amp) in the final output stage as a unity gain amplifier, all it does is convert the original stereo signal to a negative phase. This makes the 4.4mm phone out a balanced output technically, it will offer extra power and current to drive your IEM, but it won't exhibit the normal benefit of the fully balanced circuit (such as low noise, and better separation). When you connect RU6 to an external amplifier, the extra power and current is almost meaningless, it will only introduce extra noise into your signal path. So I'll suggest you start with single-ended connection.

 

[emilsoft]

Would love to see a simplistic spectrum analyser (as an option instead of displaying the sample rate) in future fw update so I can admire my sexy dongle even more whilst listening to music.

And maybe when RU7 comes along, an onboard parametric eq will be possible.

 

[musicday]

Any firmware update been released for RU6, can't access the website.

 

[eswng679]

I just purchased the RU-6 and love how it sounds with my IEMs so far. It might be a dumb question but does the RU-6 stay on if its plugged in to my computer?
Is unplugging the only way to "turn off" the unit?

 

[captblaze]

I just purchased the RU-6 and love how it sounds with my IEMs so far. It might be a dumb question but does the RU-6 stay on if its plugged in to my computer?
Is unplugging the only way to "turn off" the unit?

No on board battery, so it takes power from the transport it is connected to.

Simple answer Yes unplug is only way to "power off" the RU6

 

[eswng679]

I've been listening to the Cayin RU-6 --> 4.4 mm output --> Moondrop Variations since last Thursday. NOS with Low Gain. Source is Amazon HD via PC.
Very very good synergy. The Variations has a pretty big dip in the mid-bass. With the RU-6, the added warmth and smooth treble brings the Variations to life. I literally cannot put this combo down.

I feel like I don't need to use APO for this set up anymore. To think that I was about to sell the Variations...

Thank you @Andykong and Cayin team!

 

[rafaelroxalot]

I have bought an Unique melody Mest mk2 came with a 4.4 cable.
Anyone tried mest 2 with Ru6 and iphone 13 pro max? No problem?
Im between cayin ru6 and ua5 shangling, don't know what fits best

 

[chemosapien]

I have bought an Unique melody Mest mk2 came with a 4.4 cable.
Anyone tried mest 2 with Ru6 and iphone 13 pro max? No problem?
Im between cayin ru6 and ua5 shangling, don't know what fits best

Ua5 has better battery life(less drain on your phone) but IMHO the ru6 it's smoother more natural sound