Cayin RU7: 1-Bit Resistor Network Dongle DAC /Amp
Jul 2, 2023 at 12:19 PM Post #1,261 of 2,133
ipad to powered USB hub to RU7? did I miss any trick you have made to this setup?
Charger is connected to Hub, and charges all device
Hub distribute power and data to all port usbc
tablet see hub (OTG) usbc
usbc converter lan gigabit use direct connetion ethernet lan (no wifi latence or interference LTE/4G)
dongle is connected to hub via usbc
tablet in in charging, also, see converter lan and dongle
so, no hiss, no clic, only music with pure black
The charger supplies constant power, and the sound is cleaner that way
No special trick, only pure sound. In simple manner.
 
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Jul 2, 2023 at 12:34 PM Post #1,262 of 2,133
Has anyone been facing intermittent stutters/artifacts in DSD 256 and 128 modes while connected to smartphones?

Yes, but it might or might not be relevant to your case, or helping you to solve your problem. It can be caused by the OS of your mobile phone or your USB cable.
Maybe you can provide more information about your connection. Are you using iPhone or Android? Your IEM/Headphone and settings on your RU7 (gain, volume, All-to-DSD), your USB cable, ....
 
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Jul 2, 2023 at 1:02 PM Post #1,263 of 2,133
I use my Moto G7 Power with no Sim card as a transport via a ddHifi TC07s interconnect to my RU7. I have experienced no stuttering or artifacts on 128 or 256 on any of my IEMs.
I mostly use 128.
 
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Jul 2, 2023 at 1:50 PM Post #1,264 of 2,133
How does it pair with the Cayin C9 (via RU7 Line Out)? Is there a noticable contribution when driving easy to drive headphones/iems (i.e. Focal Stellia / Fir Xe6)?

Thanks
Short answer is yes. The c9 is the perfect amp to pair with the ru-7. One, because of the 4.4 i/o and two, because the c9 prefers a more modest amount of voltage input, ideally never going beyond 4V. It’s up to your ears whether you think an easy to drive headphone gets enough benefit from adding the c9 into the chain. However the c9 doesn’t just amplify the signal, it also provides some additional coloration to the sound, especially via the tubes. I think the c9 makes everything sound better, though with some iems it’s a small difference (Softears Twilight) and some it’s a huge difference (final e5000).
 
Jul 2, 2023 at 4:48 PM Post #1,266 of 2,133
What do you mean by prefers low voltage? What is the effect?
Not sure it is the case here, but amps have different voltage limits on their inputs. If you exceed those inputs (for example 4V into a circuit designed for 2V) you could have clipping which will result in sound degradation. The moral is that more is not always better...
 
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Jul 2, 2023 at 8:08 PM Post #1,268 of 2,133
Not sure it is the case here, but amps have different voltage limits on their inputs. If you exceed those inputs (for example 4V into a circuit designed for 2V) you could have clipping which will result in sound degradation. The moral is that more is not always better...
Not sure which review it was but they did some measuring and found that yes you get some clipping and/or distortion when feeding the c9 with more than 4V. I confirmed this when using the 4.4 LO in the ifi Gryphon at max output which I think is close to 6V, it was clipping. With the gryphon I’ll set the c9 in pre-amp mode and then adjust volume level on the gryphon, which usually sits at around 60-70 depending on the headphone. The gryphon via line out is a very nice dac for the c9 but I now prefer the ease of using the ru-7.
 
Jul 2, 2023 at 8:09 PM Post #1,269 of 2,133
Iirc, C9 is 4V, and my Fiio is 4,4V. But it is pretty close, I guess it is ok 🤷🏻‍♂️
Yeah I don’t think that should cause any issues. It’s the desktop DACs that are putting out 6V or 8V via balanced that can be an issue.
 
Jul 3, 2023 at 2:31 AM Post #1,270 of 2,133
Dear friends, here is my Cayin RU7 review for anyone interested.
With comparisons to the Cayin RU6 and iFi Go bar.

This is a solid choice and one of the best USB DAC dongles available right now.

IMG_20230626_185717.jpg
 
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Jul 3, 2023 at 2:51 AM Post #1,271 of 2,133
Dear friends, here is my Cayin RU7 Review for anyone interested.
With comparisons to the Cayin RU6 and iFi Go bar.

This is a solid choice and one of the best USB DAC dongles available right now.

Great review. Mirrors my interpretation and listening experiences. The LO feature is just brilliant that turns the RU7 into one-fits-all dongle dac. I'm thoroughly enjoying it with all genres of music. 🎶
 
Jul 3, 2023 at 5:33 AM Post #1,272 of 2,133
Dear friends, here is my Cayin RU7 Review for anyone interested.
With comparisons to the Cayin RU6 and iFi Go bar.

This is a solid choice and one of the best USB DAC dongles available right now.


The link brought me to another review on the Fiio Fw3 though. Managed to find your review on the Cayin RU7 after that. Thanks for nice review!
 
Jul 3, 2023 at 5:54 AM Post #1,274 of 2,133
Yeah I don’t think that should cause any issues. It’s the desktop DACs that are putting out 6V or 8V via balanced that can be an issue.

Depends on the loading that you are going to use with the amplifier. 6V is OK unless you drive it with very demanding loading. 8V will be too hot as line-level input.

I can't figure out the reason behind the high voltage level line-out design. What exactly is the advantage of 6V or 8V Balanced line out? To skip the need for a pre-amp so that you can use it to drive a power amp directly with the digital volume in the DAC? Audiogon has users reported that the 3V/6V output of his DAC has overloaded his amplifier. According to Shure, a line-level signal is approximately one volt and it is expressed as 0 dBV. The term "line" comes from "telephone line." When the telephone network was being developed in the early 20th century, the typical level of a telephone signal as it traveled along telephone cables was around one volt. So, one volt was a "line level" signal. The Redbook CD standard (Sony & Philips, 1982) stated that the highest output from CD is 2.0Vrms (RCA connectors). That quickly becomes the common ground for consumer electronics and professional studios.

For this reason, I don't think we should call 2V single-ended and 4V balanced as low voltage. Its the other way around IMHO.
 
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Jul 3, 2023 at 8:23 AM Post #1,275 of 2,133
HeadFi is updating its search index, so I can't quote my previous writing on this subject. I probably will write a more detail post on the All-to-DSD feature later on, but right now, let's go through this briefly.

The 1-Bit resistor network can only accept 1-bit bitstream as input, therefore we need to convert all non-1-bit audio signals into 1-bit before we can feed the source material from USB Audio to our 1-bit Resistor Network. This is where ALL-TO-DSD kicks in. In other words, if you are listening to anything that is NOT 1-bit, regardless of whether the material is stored in your local TF card or you are streaming via your subscribed service, it must be converted to DSD (i.e., 1-bit format), so DSD-64 is the default setting, and you can select DSD128 and DSD256 if your pairing is permitted. Fortunately, the conversion from PCM-to-DSD is a fairly simple and accurate algorithm, when compared to DSD-to-PCM conversion, and please don't judge PCM-to-DSD conversion based on your DSD-to-PCM experience, they are not the same algorithm in reverse.

Regarding DSD64 vs DSD128 vs DSD256, I won't assume the higher conversion is always the better. The upscaling involves an interpolation algorithm, which means they might enhance the sharpness and sense of resolution, but might compromise the naturalness of the playback. I personally prefer DSD64 with regular 44.1/48 material and DSD128 with 88.2/96 material, in other words, I am a believer of less is more when come to upscaling.

Besides draining more power, are these All-to-DSD setting providing audible differences? Yes but depends. If you are using the Dongle DAC on the go, traveling underground or by bus, or walking on a street, I don't think the difference really matters. If you are using it for critical listening with a decent resolving IEM, then you probably won't hear the difference immediately, but when you compare them after multiple ABABA , you are training your ear to look for the difference, and once you learn the tricks, the difference is fairly audible, and as I said, please don't assume DSD245 is always better then DSD64, not to every pair of ears, and not to every genre of music, IMHO.
Please correct me if I'm wrong as I don't have much technical knowledge but does the RU7's automatic conversion of all input music to DSD64/128/256 mean that there is no sound quality difference of the same track whether it be streamed either from Tidal MQA or Qobuz Hi-res or Apple Lossless, will it sound the same in any case? (apart from the user selected 64/128/256 option)
 

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