[Louisiana]

Normally the R28 would be the end of the line for me, but what bothers me a lot about the unit is this:
I am absolutely dependent on a DDC, since only DSD 128 is possible via USB, as well as PCM up to 192.
No idea why this is so, I bought the device used, so can not say for sure from which year it comes.

I have tested various DACs with various DDCs in the past, and could never hear a difference between USB and I2S. the R28 is the first device that clearly benefits from my Gustard U18.

This is why I'm only looking for a new DAC in the first place, and as much as I'd like to go back to audio GD, I just don't have room for these huge behemoths.

Today two new devices arrived for testing, once a Pontus II, as well as a Rockna Wavelight, I am very excited.
At the moment, the Pontus is connected, which will also remain so for 2-3 days before I form a judgment.

What I can say, however: With the Pontus it is again that I hear no difference between USB from my RPi4 or I2S from my Gustard U18

 

[gimmeheadroom]

Normally the R28 would be the end of the line for me, but what bothers me a lot about the unit is this:
I am absolutely dependent on a DDC, since only DSD 128 is possible via USB, as well as PCM up to 192.

From http://audio-gd.com/R2R/R2822/R2822EN_Specs.htm

Support Sampling​

USB & IIS : 44.1kHz - 384kHz /32Bit DSD64-512 Coaxial mode: 44.1kHz - 192kHz Optical mode: 44.1kHz - 96kHz​

I am pretty sure I don't understand the problem though.

 

[Louisiana]

I am pretty sure I don't understand the problem though.

I probably expressed myself incorrectly.
I know the specs of the R28, via I2S it also works exactly as it should: native DSD up to 512, and PCM up to 384.
But when I connect the device via USB, I only get max. DSD128 and max. PCM 192, I don't know why that is.
It also doesn't matter if I connect the R28 to my MAC, or Win PC, or Raspberry Pi.

According to the seller, the device is from 2020, but even they should deliver the same via USB as I2S:

 

[gimmeheadroom]

I probably expressed myself incorrectly.
I know the specs of the R28, via I2S it also works exactly as it should: native DSD up to 512, and PCM up to 384.
But when I connect the device via USB, I only get max. DSD128 and max. PCM 192, I don't know why that is.
It also doesn't matter if I connect the R28 to my MAC, or Win PC, or Raspberry Pi.

According to the seller, the device is from 2020, but even they should deliver the same via USB as I2S:

It could be you need the ASIOProxy to do more than DSD128, this sounds familiar.

USB on all my Windows PCs (around 5 near my Audio-gd setup) is good up to 768 KHz on my RME and at least DXD/352 (PCM) on my R8.

Maybe be you need to reflash Amanero on your DAC?

 

[sajunky]

I know the specs of the R28, via I2S it also works exactly as it should: native DSD up to 512, and PCM up to 384.
But when I connect the device via USB, I only get max. DSD128 and max. PCM 192, I don't know why that is.
It also doesn't matter if I connect the R28 to my MAC, or Win PC, or Raspberry Pi.

This is a known issue. DSD transfer over I2S is native.

DSD transfer over USB is DoP (encapsulated in PCM frames). Extra bits in the frames are added for DSD detection. It exceed a maximum bandwith, cause only a half speed is available. Briefly:
DSD64 is transfered in PCM 176.4kHz frames
DSD128 is transfered in PCM 352.8kHz frames
opps!!! It is approaching a maximum PCM transfer rate!

Doubling DSD rates is possible with a special transfer mode for DSD, but neither Microsoft nor Apple didn't bother to implement it. It is still possible on Windows by installing Amanero ASIO drivers, there are applications that can initiate native DSD transfers. Not sure about current situation on Apple, as developers are restricted more on every OS release.

 

[gimmeheadroom]

This is a known issue. DSD transfer over I2S is native.

DSD transfer over USB is DoP (encapsulated in PCM frames). Extra bits in the frames are added for DSD detection. It exceed a maximum bandwith, cause only a half speed is available. Briefly:
DSD64 is transfered in PCM 176.4kHz frames
DSD128 is transfered in PCM 352.8kHz frames
opps!!! It is approaching a maximum PCM transfer rate!

Doubling DSD rates is possible with a special transfer mode for DSD, but neither Microsoft nor Apple didn't bother to implement it. It is still possible on Windows by installing Amanero ASIO drivers, there are applications that can initiate native DSD transfers. Not sure about current situation on Apple, as developers are restricted more on every OS release.

But what about the fact he can't get more than 192 KHz PCM? Is that because he didn't use the ASIO drivers or because the DAC needs the Amanero reflashed?

 

[sajunky]

But what about the fact he can't get more than 192 KHz PCM? Is that because he didn't use the ASIO drivers or because the DAC needs the Amanero reflashed?

It is inconsistent as he could play DSD 128, so I take is as a mistake. Or something is wrong with Windows (old version?) [see edit]. I had some restriction on XP if I remember correctly. Win 7 requires drivers, Win 10 since Creators release can work with built in UAC 2.0 drivers at a maximum speed. Amanero drivers work in a different mode, but maximum speed is the same, it is worth to try both, as system DPC latency is different.


Edit: system mixer may restrict speed (Win 7?), but WASAPI interface is consistent. It would explain speed difference, as DSD playback require WASAPI Exclusive access, while PCM may be sent through system mixer.

 

[Louisiana]

i don't use a pc to listen to music, i just tested it on my different pcs.
Roon Rock -> RPi4 from there via USB into the DAC, and then I have the above problem.
That's why I bought a DDC, and go via I2S into the R28.

my problem for an upgrade are the dimensions of the better devices.

here is a picture with my R28, the R7 would protrude a whopping 8cm:

 

[sajunky]

Roon Rock -> RPi4 from there via USB into the DAC, and then I have the above problem.

Right, my comment was for PC as a source, irrelevant. Problem with RPi was not reported yet, may be upgrade OS is required? Other than that, there is a beta firmware on the Amanero website specific for Linux source. @gimmeheadroom mentioned about flashing it, I think it is worth to try. God luck.

 

[gimmeheadroom]

Yes, since @Louisiana reported no USB source he tried does better than 192 KHz PCM, I guess the Amanero in the DAC needs reflashing. @sajunky explanation of the DSD addresses the other issue.

Hope you get it working!

 

[Louisiana]

Hope you get it working!

Maybe that would even be the solution, but unfortunately I have no idea about it at all.
How can I rewrite the firmware for the USB module and what do I need to do that?

 

[sajunky]

How can I rewrite the firmware for the USB module and what do I need to do that?

Reflash Amanero firmware with recommended Windows optimised update for products released before 2019. Follow instruction from the website. There is a loop-back link for this forum.


Note that after you reset firmware by shorting pads you must complete a job, otherwise USB will be disabled. Check how is working, you should get PCM 384kHz playing on Windows WASAPI Exclusive output or ASIO. Your firmware could be modified by the previous owner using wrong options, it is a good idea to start fresh.

Then you can explore an option upgrading to the Linux optimised firmware to get maximum from RPi4. Before you do that, email Kingwa attaching photo of a sticker with serial number on the back, asking whether your FPGA is elligible for this upgrade. It will clarify which version you have. There is a notice that some models are incompatible with Linux optimised firmware. There is no risk of making a damage by flashing wrong firmware, but it saves trouble.

 

[Jandu]

....
How can I rewrite the firmware for the USB module and what do I need to do that?

Try
http://www.audio-gd.com/Firmware/AmaneroforLinuxEN.htm

 

[Lu Mazzmarill]

Hi! Anyone here has Experience with R28 and IEM? I have a Kinera Nan-Na 2.0 (60ohms and 110db sensitivity) and i am quite scared to fry them.
In SE with Low Gain Will they sound good?

 

[ToddRaymond]

I've used my Ocharaku Flat-4 series IEMs many times with my R28 on low gain, and I've have zero issues whatsoever. No unfortunate pops, and otherwise nothing that ever made me feel concerned that I was going to damage the IEMs or my ears.