[Andykong]

My phone is a LG G6 running Android 9 and the tablet is a Galaxy Tab A with Android 8. I used the bundled cable but also tried other ones I had lying around but without better results.

Before the RU6 I used a Dragonfly Black and not once did I run into it not being recognized. I wonder whether it might be a power issue since I noticed the RU6 draws more power than the Dragonfly and there are no issues when using a PC.

What music applications are you using with RU6? Do they support bit perfect audio output? If not, did you turn the volume of your mobile device to 100 and use the volume control of RU6 instead?

 

[Andykong]

Just received mine today after reading through most of this threads pages. I got very curious about R2R, so I decided to just try it.
I haven't had the chance to listen too much yet, but I'm enjoying the combination with the MEST MKII a lot so far. A very comfy sound, very smooth and detailed.
Between NOS and OS I prefer NOS on initial impression, but it's cool to have both options either way!

It will be interesting to see how much power it draws in my daily life since that's one of my only concerns long-term. The "plug" part of the cable connected to my iPhone/iPad definitely gets very warm. I haven't had any disconnects because of power draw so far, but I didn't try to push anything yet.
There has been some small "skips" when changing volume sometimes, but it's not too big of a deal and I'm not really changing it too much anyways after I started listening.

Hope you'll enjoy the RU6 even after the honeymoon period. I do, but my opinion didn't count.

The "skips" are caused by the switching delay of the resistor array volume control. We have explained the implementation constraint previously:

Our main hesitation with resistor array volume control is not about technical difficulties or budget consideration. The Resistor Array volume control involves switching relays when you hop from one segment to another. The relay will produce very mild pop sound with speakers and is inaudible when you are 2 or 3 meters away from the speaker. Unfortunately the pop noise will become very annoying to sensitive IEM users. For this reason, we need to mute the output for a short moment when a relay kicks in. This will introduce a small delay (around 40ms) in volume adjustment, definitely a set back from user experience point of view. For dedicated audiophiles who put audio performance, this is a small price to pay in order to implement R-2R resistor ladder network in a dongle DAC. but we can understand some users might consider this as a deal breaker, that's why we explained this in detail up front.

For more detail, please refer to the High Precision Resistor Array Volume Control section of the opening post.

 

[Andykong]

R01 is does not have NOS feature at all. Oversampled to 768 kHz or 384 kHz, if I am not wrong.

For RU6, you may want to look at the block diagram that @Andykong posted in the first page of this thread. The input signal (assuming bit-perfect) that comes into RU6 through digital audio bridge would either go unaltered (bypass oversampling filter) through to 24 bit R2R DAC (which is non-oversampling) or go through oversampling process. You have the option to chose in the setting.

I can really hear the difference between NOS and OS, and I love the former. For the price of $250, I would say implementation of NOS mode is pretty good.

If you like someone to test NOS is true or false, I think you need to find a very experienced reviewer or some one with test capabilities (which is $$$$) to evaluate all this. Good luck with that !

You are correct, R01 didn't have NOS mode. Our initial R01 design was a pure NOS approach. We didn’t have the Audio Bridge and Oversampling filter in place, the digital audio signal was feed into the Serial to Parallel Shift Register directly. The prototype performs satisfactory with standardized 24bit hi-res music files. Unfortunately we run into serious problems when we conduct further test with multi-format music library and highly sensitive IEMs. To solve the problem, we added an Audio Bridge and a high-end hardware 8x interpolation oversampling filter before the R-2R circuit, so R01 only offers OS mode by design.

The NOS mode in RU6 ovly work for PCM source. DSD bitstream will go through All-to-PCM in Audio Bridge and converted to PCM before entering NOS/OS mode selection. This is unfortunately inevitable because R-2R DAC design cannot handle PCM and DSD natively in one DSC circuit.

 

[oldkid]

You are correct, R01 didn't have NOS mode. Our initial R01 design was a pure NOS approach. We didn’t have the Audio Bridge and Oversampling filter in place, the digital audio signal was feed into the Serial to Parallel Shift Register directly. The prototype performs satisfactory with standardized 24bit hi-res music files. Unfortunately we run into serious problems when we conduct further test with multi-format music library and highly sensitive IEMs. To solve the problem, we added an Audio Bridge and a high-end hardware 8x interpolation oversampling filter before the R-2R circuit, so R01 only offers OS mode by design.

The NOS mode in RU6 ovly work for PCM source. DSD bitstream will go through All-to-PCM in Audio Bridge and converted to PCM before entering NOS/OS mode selection. This is unfortunately inevitable because R-2R DAC design cannot handle PCM and DSD natively in one DSC circuit.

Thank you @Andykong , I had already figured out that oversampling didn't do anything with DSD sources but it's nice to have confirmation it is indeed the case.

I have said in a previous post that RU6 made PCM sound like DSD. It's not quite the case when compared to a dongle DAC with a dedicated path for DSD like the Hidizs S9 AKM version.

But the RU6 certainly is the best dongle DAC I have heard for PCM. It blurs the lines between CD quality and Hi RES recordings in a spectacular manner even without using the OS mode.

This device really taught me what PRaT really is.
Only native DSD recordings on specialized DACs can exceed the sound quality and emotional impact than the RU6 offers for everything single recording you throw at it.

 

[leeperry]

I've read on another forum that transients/dynamics aren't all that on RU6 together with this link that was also posted there: https://www.l7audiolab.com/f/cayin-ru6/

Will this be changed in future fw updates?

 

[blotmouse]

I've read on another forum that transients/dynamics aren't all that on RU6 together with this link that was also posted there: https://www.l7audiolab.com/f/cayin-ru6/

Will this be changed in future fw updates?

Measurements have never played well with r-2r and don’t really matter. Your ears are the only things that matter.
Music is pleasurable due to favorable impurities and happy accidents. Tubes, distortion, etc. without those “errors” its just flat and boring.
If it was all mathematically perfect, it would suck.

 

[Andykong]

Your perspective as the engineer behind the RU6 at least has me looking around. I have to admit there are many highly rated IEMs on the market that are also very affordable (eg, 7Hz Timeless, Moondrop Kato, …). It’s difficult to tell if some of these reviews are relative to other offerings in the same price range, or if the accolades, scores, and qualifiers, are representative of all. For example, one reviewer listed all their IEM reviews, along with scores, and the scores apparently had nothing to do with cost.

Still, for a guy on a fixed income in the midst of increasing costs, it’s difficult to throw even $200 at gear I’d read about but wasn’t able to listen to. That is, I cannot help but believe I luck’d out with the RU6. On top of that, it’s difficult to believe $200 is going to up my current listening experience with the RU6, even while it’s currently matched with “inappropriately power demanding” headphones that definitely up’d my experience from a Soundblaster E5.

If RU6 users here might be aware of, or have experience with IEMs in the price range $200-$300, I’d appreciate their experience.

Regarding internet radio and services, I will turn to the CD quality streams from Radio Paradise daily, which is listener supported (also by me), but I have say the RU6 has now demonstrated to my ears the differences between lossless 16bit and lossy MP3/AAC from the likes of iTunes or Spotify. RP is highly recommended for those who want a CD quality casual background, and an up-to-date selection of today’s artists and tunesmiths.

Plenty of good IEMs in the $200-300 price range. You've named some. My favorites are UM 3DT, 7hz Timeless. You can get an Oriolus Isabellae used for around $400. Blessing 2 Dusk is $329 new. Cheaper if you buy resale.

You can pair these with an Apple Dongle or something better for $100 like a Lotoo PAW S1 used.

I own a lot of TOTL IEMs and I would total endorse these products as being very good

Right on. You don't need to buy megadollar IEM to enjoy y our music. Give me Five.

@rarewolf if you check out Cayin's product line, you probably will be surprised by number of products we are making, and they span across a very wide price range. We have integrated tube amplifiers from $400 to $8,000 (the lower-end items are exclusively for domestic market, the shipping cost and maintenace cost is too high to market time internationally), and from $250 RU6 to $3,699 N8 Brass Black, and there is a story behind this crazy practise.

Cayin was founded in 1993, and a lot of our customers probably aren’t aware that Cayin is a state-owned company. We are a subsidiary of Aviation Industry Corporation (AVIC) of China, a state-owned aerospace and defense enterprise. Back in the early 90’s, the President of AVIC was a dedicated audiophile, he wanted to contributed to the society by promoting music appreciation, so he gathered several engineers and started the Zhuhai Spark Electronic Equipment Co., Ltd. The company started off as an OEM shop and develop tube amplifiers under the name of Spark. Our product carried distinctive cultural connotation and span over a very wide price range because we are determined to make music accessible to all sectors, not just the high net worth group.

So Cayin honestly believes that everyone should be able to appreciate and enjoy music , and we build audio products to realise this conviction.

 

[Andykong]

Well now… add Meze Rai Solo to the short list for further study. I do note these aren’t as easy to drive as are the Kato or the Timeless. It would be interest to hear from @Andykong regarding whether these are outside the RU6’s sweet spot with respect to power demand and getting power from an iPhone(?)

Meze Rai Solo, silver 4.4mm cable:

on Low gain, volume is 30db (to match my Focal Elegias which were at 40db). Sound is much warmer than the Elegias. More bass quantity, but less accurate attack/decay.

You probably won't believe this. RU6 + Rai Solo is my standard "accessories" when I use my mobile phone for music. I am more on casual side when I use this setup: from Youtube to Tiktok, from Spotify to KKBox. While I have other setup for critical listening, the RU6 + Rai Solo probably pick up more hours than my N6ii + Rai Penta (and Mest II).

The Rai Solo is a fairly easy loading among sihngle DD IEMs. I have no problem to enjoy it with RU6.

 

[Andykong]

I've read on another forum that transients/dynamics aren't all that on RU6 together with this link that was also posted there: https://www.l7audiolab.com/f/cayin-ru6/

Will this be changed in future fw updates?

There is no plan to modify RU6 sound signature or audio performance via firmware update. In fact, Cayin has never modify or "rescue" the audio performance of our products through firmware update. This is not our practise.

No comment on the l7audiolab review you have quoted, my only advise is to check out the RU6 with your own IEM and music. If you can't do that, than read more reviews, don't just make up your mind with one review. Check out impresson from actual users in this thread will also helped.

By the way, do you read Chinese? or you read that article through online translatoin tool?

 

[ssriram2791]

There is no plan to modify RU6 sound signature or audio performance via firmware update. In fact, Cayin has never modify or "rescue" the audio performance of our products through firmware update. This is not our practise.

If people are looking for analytical sound (which could sound cold/sterile and boring) , they should follow the measurements... If you are looking for some exciting and lively sound and not think about technical jargons like distortion and SINAD, then Cayin has covered you pretty well with RU6 and other products in their lineup.

 

[rarewolf]

You probably won't believe this. RU6 + Rai Solo is my standard "accessories" when I use my mobile phone for music. I am more on casual side when I use this setup: from Youtube to Tiktok, from Spotify to KKBox. While I have other setup for critical listening, the RU6 + Rai Solo probably pick up more hours than my N6ii + Rai Penta (and Mest II).

The Rai Solo is a fairly easy loading among sihngle DD IEMs. I have no problem to enjoy it with RU6.

Thanks Andy! Believe me, I am giving the Rai Solo a very hard look. However, I believe I’ll end up with the Moondrop Kato. It seems many users are very happy with the Kato line of IEMs, and it seems safe for entry level and it should suit my listening habits without equalization. The Crinicle collaboration with See Audio (the “Midnight”) also looks very interesting, but too new… but then, my birthday is only 2 months away…

 

[Andykong]

I do hear the difference between NOS and OS too and I do prefer NOS as well. I think it makes FLAC sound like DSD, which is an incredible achievement.
I am just curious and surprised that more people aren't talking about the world first NOS R2R portable DAC/amp.

We have 117 pages in this thread where people have discussed, provided impressions and criticisms of the product as well.

I think this has been quite well received and has been a massive success for Cayin (@Andykong can chime in) and those who have liked this have kept this and sold other popular dongles in this forum. I think it is all down to synergy and music that you enjoy ! Keep listening !

Well, to certain extend, RU6 is aimed at a very small niche market inside a niche market, we are not feature packed, we can't go wireless, we can't MQA, we can't EQ, we didn't mearsure well, .... and we are fairly expensive among Dongle DACs, so I am not surprised that we are not as popular as other Dongle DACs in the market. Besides, we don't have a social media team so not suprsied that you'll only find relevant discussion when you know where to look for.

 

[ssriram2791]

Well, to certain extend, RU6 is aimed at a very small niche market inside a niche market, we are not feature packed, we can't go wireless, we can't MQA, we can't EQ, we didn't mearsure well, .... and we are fairly expensive among Dongle DACs, so I am not surprised that we are not as popular as other Dongle DACs in the market. Besides, we don't have a social media team so not suprsied that you'll only find relevant discussion when you know where to look for.

Leave all those aside, I have never seen a manufacturer that has been constantly engaging with their customers in Headfi as much you do Andy.

I think when someone buys a product and after sales support is not there, they lose touch with the brand and typically don't come back.

You have been at the forefront of connecting with everyone's queries and answering them with best intention and knowledge/expertise you have. You are also very open and transparent about what the product can or cannot do, not just for RU6, but for other products in your lineup as well.

I believe you will retain the user base as long this connect (conversations in Headfi) exists. Keep continuing the good work !

 

[schnesim]

What music applications are you using with RU6? Do they support bit perfect audio output? If not, did you turn the volume of your mobile device to 100 and use the volume control of RU6 instead?

Yes, volume is set to max. And WHEN the RU6 is detected, it works with all apps I tested. USB audio player pro, Tidal, even Spotify.

Rebooting phone/tablet and resetting options didn't help either.

 

[ssriram2791]

Yes, volume is set to max. And WHEN the RU6 is detected, it works with all apps I tested. USB audio player pro, Tidal, even Spotify.

Rebooting phone/tablet and resetting options didn't help either.

USB debugging is enabled in developer options, and still it doesnt work, correct ?

Not sure what other usb settings might be hidden in android.