Multiple things, LG v35 with UAPP, Ibasso DX160, PC, Tablet.. It does not matter, the result is always the same, because as I said, it is not a static I believe it is just imperfection of the DAC.
Unfortunately I still am unable to understand what you are describing and it would seem as if you've already made up your mind rather than figure out if it's an isolated problem with your gear or your particular RU6.
Well, did you try what I suggested? lower the source volume almost to 0 and increase it on the DAC, and pay attention to what happens to noise during volume steps. I feel like you are the one disregarding my claims without checking it. If I hear any counter arguments or counter evidence to what I say I will change my mind easily.
Cayin tested numerous off-the-shelf volume options, unfortunately they cannot meet the high precision, low noise, and low power consumption requirements in dongle DAC application. For instance, we have used PGA2311A in several DAPs and R01 Audio Motherboards, we tried to repeat the trick but the RU6 developed unacceptable background noise. There are better volume chipset in the market, but they are either too big physically, or drain a lot of power, making it inappropriate for Dongle DAC application. Eventually Cayin bite the bullet and developed a high precision resistor array volume control circuit that provides 99 steps volume control through 9 segments of resistors and switching relays.
Resistor Array volume control is not a new technologies, it have been around for a very long time. They are very high quality volume control design, extremely transparent when implemented correctly and you can find them in a lot of high-end preamp and integrated amplifies. Each segment of resistor array can only provide ~10 steps of volume control, this is obviously not enough in real life application, so you need to "hop" to another set of resistor array for another 10 steps, and so on, and so on.
We don't recall anyone used resistor array volume control in a Dongle DAC, probably not even in portable DAP. There is no way we expected this final outcome when we started the RU6 project back in early February 2021 (when we completed R01 R&D). We basically completed the RU6 circuit design in very fast track but we stuck at the volume control issue for 3 months trying different solutions and going nowhere. Using Resistor Array Volume Control is our final trump card. It is basically an out of proportion implementation for Dongle DAC and that us another month to finalise the furrent 9 segment resistor array design.
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.
I am not doing this, of course. It was just to demonstrate issue that is difficult to notice without reducing volume (but is still there at max volume during very very quiet parts of music).
I am not experience noise during switching, what I said is that noise that is already there increases at these volume steps (and is constant during other volume steps).
I stand corrected, I trust that it is not digitally controlled, but could you please explain why the noise behaves the way I showed on diagram? Or would you say I am wrong about this and noise always increases proportionally at every step?
First of all, thank you for responding.
I am not doing this, of course. It was just to demonstrate issue that is difficult to notice without reducing volume (but is still there at max volume during very very quiet parts of music).
I am not experience noise during switching, what I said is that noise that is already there increases at these volume steps (and is constant during other volume steps).
Here is the quick image to demonstrate what I meant all this time, and I could not communicate well enough, since everyone misunderstood.
I stand corrected, I trust that it is not digitally controlled, but could you please explain why the noise behaves the way I showed on diagram? Or would you say I am wrong about this and noise always increases proportionally at every step?
Thanks a lot for this very informative answer.
If you tried the test I described, lowering volume of the source and increasing it on the RU6 and then checking the noise levels you would know right away what I am talking about, because it is very apparent.
That’s why I said the USBC version was coming soonI talked to ddHiFi and I believe they will be working on usb-c adapter version, similar to the one above with a separate data and charging ports. Otherwise, just go with a usb-c splitter, I have one, talked about it before in this thread, it works, but adds bulk. Plus, many companies that make these splitters use cheaper usb-c connectors. ddHiFi quality is usually better.
For now, your alternative is something like this:
tried multiple cables as well as connecting to my macbookj.
Sounds like ur RU6 connector plug is indeed faulty. Call your dealer~
