[TYATYA]

This is great news, as this means that most, I for sure, can use the "cleaner" 3.5 instead of 4.4 and stay within 80% where the sound is again "cleaner".

Heard or not heard the difference depending condition and individual but we may all understand:
Relate to noise catching will be amply by a scale so should not use relatively low volume.
Relate to output quality (from dap), more volume level got more distortion.
Manufactures usually show audio specs at certain volume output ( i do believe that is best or near the best value).

H mode sound grainy than L mode, to my ears.

Older versions fw of SP1000 just allowed max 2.0V but years later they releas fw allow 4.0V

 

[TYATYA]

Today I 1st time curious if Ru6 can produce ultrasonic, example 25kHz properly.
Result: not sure it can or cannot (I have no criteria to evaluate).
Noise heard clear as you listen to a average dynamic track by a typical headphones at volume lvl 4/100, L gain, 4.4 jack.
It should be completely silence.

Specs sheet, frequency 20-20k.
Ru6 support 384Khz input.

With 1Hz-96Khz (sampling frequency 192k) signal input, Ru6 sound much clean if force it to work at 44.1, we listen to what human can, other thing we cant heard become dead silence

 

[MrWalkman]

frequency 20-20k

I'm 100% sure that somewhere official I saw it listed with 20-40 or something like that, but I can't find it anymore...

 

[TYATYA]

I'm 100% sure that somewhere official I saw it listed with 20-40 or something like that, but I can't find it anymore...

From Cayin:

I understand it does not mean beyond 20k is impossible

 

[Yanec]

I'm 100% sure that somewhere official I saw it listed with 20-40 or something like that, but I can't find it anymore...

The 40kHz is just typical marketing. It is neither delivered in reality nor needed.

Not needed:
20-40kHz is needed just to scare away bats. In best case our hearing is up to 20kHz, usually lower. Recordings have a 20kHz cutoff too. If there is any whatsoever energy beyond 40kHz it is not signal just noise, which might create harmonics negatively impacting signal below 20kHz.

Not real:
- OS is filtered at 20kHZ to cut out the noise that was shifted beyond 20kHz during oversampling. If it was left to extend beyond 20kHz it would be worse as mentioned above.

- NOS is already -2.5db at 20kHz which is absolutely normal and expected. The theoretical output of a DAC without oversampling follows a sinc function, which inherently rolls off at higher frequencies. This is due to the way the samples are reconstructed into a continuous signal, where the sinc function's side lobes diminish in amplitude as frequency increases, leading to a decrease in high-frequency content.

NOS upper treble actually sounds very good with a small difference from OS because of the gradual slope and just 2.5db maximum delta. Very often for the better in my opinion.

 

[Yanec]

I have been trying the RU6 with many iems to find good synergistic combinations.

I subjectively think I found a very good one, will skip the iem description as off-topic. The key takeaways: detailed high end BA in the mids, and high-end ESTs in the highs synergise well with the RU6. They both compensate for certain nos r2r shortcomings while highlighting strengths. The dual DD chamber sub makes the bass even more fun yet quite well control. The stage illusion is the widest out of the combos I've tried.

 

[TYATYA]

I try to feed ultrasonic (mean sound pressure is more than zero with above 20k) to Ru digitally then connect output of Ru6 to Shure1500 amp.
The indication bar of the amp blinks -> Ru6 can out put more than 20k.
On the other hand, I force R6 to work at 44.1k then I see no blink of indicator bar -> all is cut off or is not reproduced by Ru6 (in 44.1 mode).

So, cut off graphic shown 20k may be you measurement at 44.1 mode.

However I agree more than 44.1 is not need when playback but for producers.
In the worst case, 44.1 mode will eliminates all ultrasonic signal if it comes with the mix

 

[Yanec]

I try to feed ultrasonic (mean sound pressure is more than zero with above 20k) to Ru digitally then connect output of Ru6 to Shure1500 amp.
The indication bar of the amp blinks -> Ru6 can out put more than 20k.
On the other hand, I force R6 to work at 44.1k then I see no blink of indicator bar -> all is cut off or is not reproduced by Ru6 (in 44.1 mode).

So, cut off graphic shown 20k may be you measurement at 44.1 mode.

However I agree more than 44.1 is not need when playback but for producers.
In the worst case, 44.1 mode will eliminates all ultrasonic signal if it comes with the mix

Yes, Redbook 44.1/16, indeed might be going beyond 22kHz with higher resolution material, not that it makes sense.

The RU6 doesn't have the Dynamic Range to play transparently anything higher than 16bit sources anyway.

BTW, the vast majority of higher resolution material is simply upsampled. Most contemporary master recordings and all older master tapes don't go beyond 44.1/16. Upsampling if anything can only degrade quality, not improve it.

If the RU6 is let to create output beyond 20kHz for higher res then I recommend using OS mode for 96 or 192 source material. That's because in NOS mode the noise floor grows very quickly and very high beyond 20kHz and would impact the sub-20kHz negatively too.

NOS is still my clear preference for 44.1 though and that's the resolution where the RU6 makes sense and "shines". And recordings are predominantly 44.1 anyway.

Cayin's manual for the RU6 BTW states 20-20k a bit confusing:

And from the very first post in this thread by Andykong:

 

[Audiofilobrpt]

Hello friends!!
Have any of you faced an issue with graphics on your RU6 screen not working?

I had 2 RU6 units. After selling a unit that was working perfectly recently, I went to get the other RU6 that had been unused for over 6 months for my own use.
When I picked it up to use it now, I was surprised by the screen with problems with letters and numbers.

The sound comes out divinely well, that’s the most important, but the screen now looks like this.

Is there any magic we can do to solve this or is the screen on my 2nd RU6 dying?

I'm glad I sold the unit that was perfect for the buyer.

Could it be that the reason was that it was turned off for a long time?

 

[AlexCBSN]

My beloved ru6 has a new sound effect, after using it for 15 or 20 minutes, it starts making a clicking sound in the left headphone (balanced out). It sounds … funny, in some tracks it can get masked but lately I’ve been listening to a lot of acoustic tracks and it definitely goes noticed and quite annoying. Does anybody else noticed something like it? I’m ok with it for now, probably will get a second unit or try the ru7… or wait for the ru8 which might make an appearance this year or next. Another funny thing is that my Cayin n6ii has stopped working with tidal in certain tracks. I’m thinking an OS update needed but since its been 4 years since its appearance i think support its done for good