[Yanec]

You have started your reply in extremely rude manner though I can see that your thread has been edited now.

The world of metrology my biggest hobby. I may not spend decades on this, but I know what I am talking about.
As you correctly pointed out 0.01% tempco refers to an individual resistor, but…

Referring to matching pair, there are several manufacturers like Vishay, doing voltage dividers i.e. a matching pair of resistors with a very tight tempco. There is a guy called Edwin Pettis in the USA who manufactures precision resistors and others.
It is possible to test tempco of an individual resistor or a pair at home in a small self-built oven connected to a PC or a Raspberry Pi running a Python script.

Actually as we speak I have on my desk several matching pairs of resistors with 1ppm or 0.0001% (this is not individual tempco but a matching resistors ratio tempco). These were custom made for me at a lab.

I agree with you building at home anything 12 bit or even 16 bit is very hard. And anything with more than 20 bit is literally impossible.

The point of this discussion is that 0.01% or better tempco matching resistor pairs are available at home. Of course they are expensive and custom made and have to be ordered with a long lead time. I shall rest my case now as a half-informed forum expert lol )

The point was stated clearly: you cannot assemble a r2r ladder at home that operates transparently - at least 0.01% in actual operations needed for 16bit audio. As I said it is not the same as buying online a resistor. Test measurements of a device you did build at home are the only thing that can prove me wrong.

No intend being rude with you, prefer friendship. You were blunt to call me out wrong, you received a reply in the same manner. Peace brother, live is good!

 

[Andykong]

May I suggest moving the R2R discussion away from RU7 thread? RU7 is not a R2R DAC and we have our share of confusion in the past, certainly not a good ideas to include more R2R discussion or debate in the thread, and attracting more users looking for R2R product to RU7 through searching function.

Maybe continue the discussion in RU6 thread is viable?

 

[Yanec]

May I suggest moving the R2R discussion away from RU7 thread? RU7 is not a R2R DAC and we have our share of confusion in the past, certainly not a good ideas to include more R2R discussion or debate in the thread, and attracting more users looking for R2R product to RU7 through searching function.

Maybe continue the discussion in RU6 thread is viable?

I believe all the exchange above should be deleted if possible - it doesn't add any value here.

In my 1st message I provided technical details why the RU7 isn't R2R. To avoid potential confusion caused by Srboljub's video review. That might be the only message worth leaving.

 

[Lohb]

Hi !
Is going balanced TRRS to TRS portable tube amp going to give any benefit vs just single-end TRS to TRS to a portable tube amp ?

 

[Edward Ng]

Hi !
Is going balanced TRRS to TRS portable tube amp going to give any benefit vs just single-end TRS to TRS to a portable tube amp ?

Probably not. The converter just throws away the negative signal on each side, which then makes it like any other single-ended signal.

-Ed

 

[Daniel4IEM]

I bought my Cayin RU7 around end May last year (I think it should be one of the pioneer batches).

Can't vouch for the later batches, but I review IEMs, and the Cayin RU7 is one of my staple sources used for evaluation (both 3.5 mm and 4.4 mm outputs). During testing, I probably disconnect and connect around 5 - 10x per review on the RU7. I also use the RU7 at least twice a week for general music listening too, and haven't faced any issues thus far (touch wood).

Curious to hear about quality from anyone who has purchased recently in the US. I am hoping the issue is resolved and I can purchase confidently

 

[akukula]

Curious to hear about quality from anyone who has purchased recently in the US. I am hoping the issue is resolved and I can purchase confidently

I purchased my RU7 a couple months ago. Took them on a 3 week trip with me. Been using them from time to time since then. Been very satisfied with it. Better sounding cpmpared to ny Questyle M15 to my ears. Only issue I have is it needs a lot of power. Once my iphone battery level hits 80% then it wont work.

 

[Edward Ng]

I purchased my RU7 a couple months ago. Took them on a 3 week trip with me. Been using them from time to time since then. Been very satisfied with it. Better sounding cpmpared to ny Questyle M15 to my ears. Only issue I have is it needs a lot of power. Once my iphone battery level hits 80% then it wont work.

Are you using All to 256? Try All to 128 or even 64; the lower resolution settings draw less power.

The issue is primarily with iPhones that have Lightning ports—they don’t give enough juice. 15th generation iPhones and DAPs that use USB-C ports are okay with any setting.

-Ed

 

[Yanec]

Curious to hear about quality from anyone who has purchased recently in the US. I am hoping the issue is resolved and I can purchase confidently

I could help, but I am not in the US and your question is for anyone in the US.

Joke aside the quality is the same for any region, China hasn't yet reached the genius idea to troll US customers specifically.

Overall Cayin, unlike HiBy, have implemented a robust QC system. Their facilitates are also not garage enterprise, they invested serious capex in these. I have never heard or read about mass quality issues.

 

[Yanec]

I purchased my RU7 a couple months ago. Took them on a 3 week trip with me. Been using them from time to time since then. Been very satisfied with it. Better sounding cpmpared to ny Questyle M15 to my ears. Only issue I have is it needs a lot of power. Once my iphone battery level hits 80% then it wont work.

Laws of physics. Power out requires power in.

Android phones don't have the ridiculous Apple limitations to power, Apple enjoy limits and restrictions... Anyway, the new models don't have that silly port power limit so with them it's fine.

 

[okan]

Curious to hear about quality from anyone who has purchased recently in the US. I am hoping the issue is resolved and I can purchase confidently

I've bought mine a month ago. It stopped working after 2 days. Musicteck replaced broken one immediatly and the new one is flawless. There were no issues with ports by the way with the old broken one also. I didn't try ru7 with full size headphones but it is great with my iems that is why I also use it with my desktop daily.

 

[Daniel4IEM]

thanks all.
I should have specified more in my question. The quality issue I was referencing was one discussed in this thread about the internal parts of the 4.4 mm port breaking. Seemed like it was a recent production problem