[ethan60]

Probably it's my english..

1. Never, never.. Never had problem with PCM files.
2. I started to use DSD files only from the last months.
3. No partially flashing of FPGA occurred. For sure. The JTAG chain was never detected and the fail upgrade results immediately after pushing "start".
4. Never I attemped to flash DA-8 modules.
5. Just as said, the setting of soft players are rights.......ASIO drivers, 24 bit output etc.. Setting are rights.. for sure.
Software players from PC connected by USB or other hardware sources connected with I2S, when using DSD provide music on both channels, but with a lot noise in the right channel. It happens both with speakers and headphones.
All is fine with PCM files including the upsample to 384 Khz

Thanks again for the support
I hope about suggestions from the forum members for a correct way to flash the FPGA of my R28.

 

[aravaioli]

I guess I should report my experience last year with the R28 2022.

While I never thought I was missing anything, curiosity once again had the best of me and I acquired a Cayin HA-3A, an Aune S17 Pro and eventually a Matrix Audio Mini i3.

Starting from the end, I now have kept only the R28 and of all of the above the Matrix i3 is still for sale (here, eventually on Feebay).

The S17 Pro is possibly the warmest of the bunch, only matched by the Mini i3 which, however, is not nearly as powerful. Power is about on par with the R28, perhaps slightly below it. I have no intention to destroy my ears and I do not test the limits of what I have: however when both in high gain the R28 volume level needed for my HE1000 Stealth to reach 85 dB is 34, while on the S17 Pro is 40. When fed by the same DAC, both are very spacious sounding, an area where the Matrix i3 doesn't compete.

The HA-3A is a strange animal. It is very powerful, in particular with high impedance headphones. Copes well with planars too, however with my DCA Ether 2 it was straining a bit with the volume knob at 1 o'clock. Certainly a well-refined, wide-sounding and hyper detailed amplifier which, to my ears, does not sound "tubey" at all. And tube rolling did not help enough. I still hold it in high consideration and it is other than unlikely that I will own it again later on, however I also let that go since the R28 retains more headroom with some planar headphones I have and the sound is rather close (a bit more relaxed in the mids, where the Cayin is quite forward). Also interesting, I bought it to match with my HD650 (still one of my most used headphones) and I later discovered that the budget priced iFi Zen Can Signature 6xx (180£ open box) does just as well with the 6xx button engaged.

The Matrix Audio Mini i3 was bought as an all-in-one solution for my office. I also plugged it to the R28 and the S17 with its analog out because I found its DAC section very interesting. In my view this sounds more tubey than the HA-3A (already sold, hence I could not couple with it)! The path to a warmer/smoother sound is there, no need for R2R (and certainly not any R2R dac) and in fact I might hold into it just because of that. The amplifier section is also quite good, with the HE1000 I could not set it apart from the S17 when volume matched, but there is not a lot of power to spare as I found myself at -5 dB. I hate the lack of Tidal connect as I am an Android user and have no money to spare for a Roon subscription.

Overall the amplifier section of the R28 seems to get less praise than the R2R DAC and I beg to differ. The DAC in the R28 is as detailed as a delta-sigma (if not more) and has a nicely extended soundstage, certainly larger than the ES9038Q2M of the Matrix Audio i3, but it is not on the warm side. I personally find it clinical and I actually do not mind, since I have the R28 also connected to a Mojo which provides a very different sound delivery, more intimate and organic. The Matrix Audio i3 DAC is very close to the Mojo, in fact.
Based on my personal experience I found the amplifier section to stand up more in the R28 vs the competition. Given the cost of R2R dacs, you almost get the amplifier section for free when choosing the R28, and at a significant saving vs the Gustard R26 DAC only (never heard and I doubt I'll ever do).

The reason why this model doesn't get more attention here and in other forums is just the fact that Audio GD does not send around the globe free units to the various YouTube promoters we all know. I believe only Currawong has reviewed a unit and it was well-praised.

 

[svmusa]

I guess I should report my experience last year with the R28 2022.

While I never thought I was missing anything, curiosity once again had the best of me and I acquired a Cayin HA-3A, an Aune S17 Pro and eventually a Matrix Audio Mini i3.

Starting from the end, I now have kept only the R28 and of all of the above the Matrix i3 is still for sale (here, eventually on Feebay).

The S17 Pro is possibly the warmest of the bunch, only matched by the Mini i3 which, however, is not nearly as powerful. Power is about on par with the R28, perhaps slightly below it. I have no intention to destroy my ears and I do not test the limits of what I have: however when both in high gain the R28 volume level needed for my HE1000 Stealth to reach 85 dB is 34, while on the S17 Pro is 40. When fed by the same DAC, both are very spacious sounding, an area where the Matrix i3 doesn't compete.
The HA-3A is a strange animal. It is very powerful, in particular with high impedance headphones. Copes well with planars too, however with my DCA Ether 2 it was straining a bit with the volume knob at 1 o'clock. Certainly a well-refined, hyper detailed amplifier which, to my ears, does not sound tubey at all. And tube rolling did not help enough. I still hold it in high consideration and it is other than unlikely that I will own it again later on, however I also let that go since the R28 retains more headroom with some planar headphones I have and the sound is rather close (a bit more relaxed in the mids, where the Cayin is quite forward).
The Matrix Audio Mini i3 was bought as an all-in-one solution for my office. I also plugged it to the R28 and the S17 with its analog out because I found its DAC section very interesting. In my view this sounds more tubey than the HA-3A (already sold, hence I could not couple with it)! The path to a warmer/smoother sound is there, no need for R2R (and certainly not any R2R dac) and in fact I might hold into it just because of that. The amplifier section is also quite good, with the HE1000 I could not set it apart from the S17 when volume matched, but there is not a lot of power to spare as I found myself at -5 dB. I hate the lack of Tidal connect as I am an Android user and have no money to spare for a Roon subscription.

Overall the amplifier section of the R28 seems to get less praise than the R2R DAC and I beg to differ. The DAC in the R28 is as detailed as a delta-sigma (if not more) and has a nicely extended soundstage, certainly larger than the ES9038Q2M of the Matrix Audio i3, but it is not on the warm side. I personally find it clinical and I do not mind, as I have also connected to a Mojo which provides a very different sound delivery, more intimate and organic. The Matrix Audio i3 DAC is very close to the Mojo, in fact.
Based on my personal experience I found the amplifier section to stand up more in the R28 vs the competition. Given the cost of R2R dacs, you almost get the amplifier section for free when choosing the R28, and at a significant saving vs the Gustard R26 DAC only (never heard and I doubt I'll ever do).

The reason why this model doesn't get more attention here and in other forums is just the fact that Audio GD does not send around the globe free units to the various YouTube promoters we all know. I believe only Currawong has reviewed a unit and it was well-praised.

Nice writeup and thx for sharing your impression on these 3 different products. I myself acquired a used 2021 R28 last week and as a previous owner of Aune S17 pro I agree with your assessment on R28. R28 dac is not warm but detailed and smoother sound as per say, compared to my SMSL SU9 dac I find it way much better in highs wherein the details are not lost without introducing shrills and accentuated air around notes. The bass on R28 is the best I have heard so far, Mids are realistic and natural. The amp/dac both are dead quite with no noise to pick on even my sensitive Meze 99 neo headphones, I am now able to listen to my old CD's and the most impressive feat was for me to use my Beyer DT770 on R28, this one has such a fatiguing highs I rarely use it on solid state gear but with R28 I can use it like any other headphones.

I am impressed with Audio-GD, was a bit apprehensive initially but now I am curious how their higher end gear might sound, given the R28 is such a great DAC/AMP and will eventually explore on acquiring the HE range AMP and DAC separates is my goal.

Surely very underrated brand.

 

[aravaioli]

Nice writeup and thx for sharing your impression on these 3 different products. I myself acquired a used 2021 R28 last week and as a previous owner of Aune S17 pro I agree with your assessment on R28. R28 dac is not warm but detailed and smoother sound as per say, compared to my SMSL SU9 dac I find it way much better in highs wherein the details are not lost without introducing shrills and accentuated air around notes. The bass on R28 is the best I have heard so far, Mids are realistic and natural. The amp/dac both are dead quite with no noise to pick on even my sensitive Meze 99 neo headphones, I am now able to listen to my old CD's and the most impressive feat was for me to use my Beyer DT770 on R28, this one has such a fatiguing highs I rarely use it on solid state gear but with R28 I can use it like any other headphones.

I am impressed with Audio-GD, was a bit apprehensive initially but now I am curious how their higher end gear might sound, given the R28 is such a great DAC/AMP and will eventually explore on acquiring the HE range AMP and DAC separates is my goal.

Surely very underrated brand.

Probably not considered high end (will be end for me, at least for a while....) but my HE1000 Stealth matched slightly better with the S17 Pro. The opposite happens for the Dan Clark Audio Ether 2, which performs better with the R28. Great match for LCD-X and LCD-2 also.

 

[ethan60]

Upgrade firmware issue R28
For the flash of FPGA with Quartus software it could be possible that I must use:
Active serial programming???? instead of... Jtag...????

"In the mode drop down selection box select 'JTAG' for CPLD devices or 'Active serial programming' for FPGA device"

 

[aravaioli]

I eventually found a better amplifier section with the iFi iCan Pro Signature: but that's 2x the brand new price of the R28 and with no DAC, so the value of the R28 remains unrivalled.
IFi hooked me on the xBass feature which works very well in many situations. It is implemented well also in their low cost systems, btw, and the Zen Can Signature 6XX still blows my mind for how good makes my HD650 sound.

 

[Chris Kaoss]

Yes. Even as a preamp, the R28 will hold its value with a clean and transparent sound, at least with my active floor standers.

Can't ask for more in that regard.

 

[sajunky]

I eventually found a better amplifier section with the iFi iCan Pro Signature: but that's 2x the brand new price of the R28 and with no DAC, so the value of the R28 remains unrivalled.
IFi hooked me on the xBass feature which works very well in many situations. It is implemented well also in their low cost systems, btw, and the Zen Can Signature 6XX still blows my mind for how good makes my HD650 sound.

Yes, I remember FiiO E12A Mount Blank, it had a lovely bass boost supporting 120 beats per second music. However sound quality suffered from using opamps, immediately noticed in synthetic treble, but also in the mids on the long run. A big contrast with a delicate soft and detailed vocals, while violent dynamic of my R2R-11 amp.

 

[svmusa]

I also see loss of micro details feeding my R28 to ArtEQ 32 band equilizer, I gather this is opamp based device internally and I have had it for long time, but the R28 shows the limitations of the device.

I am kind of scratching my head for a suitable balanced SS headphone amp to pair with R28 without sacrificing the details but smoother on the highs a bit for my ears. Opamp based amps are a question mark at this time for me.

I think master 19 might not make it smoother is my thinking given its transparent and neutral output. Violectric v281/v222 are some choices but would love to hear some other options. Aune s17 pro is a great choice but I have had issues with thier volume settings.

I played with all sample rate settings and landed on OS4 as a middle ground for speakers and OS8 for headphones. On the contrary to what manual says I find these 2 modes better balanced in dynamics and smoother sound compared to NOS mode, rest are a bit too much details for me particularly on old CDs with so so recording.

I cannot imagine having more detailed DAC than R28, unless the source is great to benefit from such a capable device. I am running spotify with 32bit and 48khz windows 10 sampling, I tried other rates, the higher you go you get more thinner and over accentuated highs.

 

[sajunky]

I am kind of scratching my head for a suitable balanced SS headphone amp to pair with R28 without sacrificing the details but smoother on the highs a bit for my ears. Opamp based amps are a question mark at this time for me.

Amp won't fix jitter, it could be a cause. Smoothing jittered sound in the amp will lose details.

2021 version is my favourite, but ports are not isolated. If you like this DAC, you should check whether there is upgrade kit with USB isolation. As an alternative, care should be taken for cleaning USB source from ground loops. It can be very simple method like adding self-powered USB 2.0 hub or inexpensive Ifi Defender to the ultimate solution which was always DI-20HE, now replaced with DI-24HE.

I am running spotify with 32bit and 48khz windows 10 sampling, I tried other rates, the higher you go you get more thinner and over accentuated highs.

Oh, it can be a problem, Windows mixer. Spotify is problematic, as the app won't allow to use bit-perfect interface like WASAPI exclusive or ASIO. Get a trial from the other provider, Qobuz is known for the best SQ. Reduce volume by few dB to avoid activating a limiter.

Also try Foobar 2000 with downloaded files and compare quality.

 

[svmusa]

Amp won't fix jitter, it could be a cause. Smoothing jittered sound in the amp will lose details.

2021 version is my favourite, but ports are not isolated. If you like this DAC, you should check whether there is upgrade kit with USB isolation. As an alternative, care should be taken for cleaning USB source from ground loops. It can be very simple method like adding self-powered USB 2.0 hub or inexpensive Ifi Defender to the ultimate solution which was always DI-20HE, now replaced with DI-24HE.


Oh, it can be a problem, Windows mixer. Spotify is problematic, as the app won't allow to use bit-perfect interface like WASAPI exclusive or ASIO. Get a trial from the other provider, Qobuz is known for the best SQ. Reduce volume by few dB to avoid activating a limiter.

Also try Foobar 2000 with downloaded files and compare quality.

I am using optical out from my CD transport and feel the same sound signature, is this also prone to Jitter?

It could be my old ears, I am used to old vintage gear sound and the modern gear is hyper detailed which has its pros and cons.

 

[sajunky]

I am using optical out from my CD transport and feel the same sound signature, is this also prone to Jitter?

It could be my old ears, I am used to old vintage gear sound and the modern gear is hyper detailed which has its pros and cons.

Optical is the worst for jitter. Also there are only few CD transports with low jitter, these are very expensive. These two factors are cumulative. If sound is similar to USB, it confirms my suspicion that things can be improved a lot on the USB port.

You can rip your CD in Foobar or EAC and play in Foobar using WASAPI Exclusive ot ASIO output, compare results. USB should sound much better as there is no jitter on the interface, but ground loops frequently have devastating effect on D/A conversion. Cleaning USB port can bring the biggest improvement ever.

My ears are also old. Modern recordings can be poor quality, mastered to sound the best on the average equipment. Loudnes war is over, but there is still lot of content with DR-5 to 7. These sound not good on the hi-res system, compression is not to my taste. Original CD's frequently sound better than remastered new releases, but it is a different story.

In future look for audiophile labels like ECM, Stockfish Records, Linn, etc. However for now some work needs to be done.

 

[Chris Kaoss]

Wonder what dedicated devices out of the AGD line up could replace my R28 at a reasonable cost factor?
Well, there should be an upgrade anyway. ^^
Not that I want to replace the R28 in the near future, but still curious about the options.

Imo, it's the best option to drive nearly all headphones with a rather small footprint (from an AGD point of view )
Plus, a great preamp for sure.

A 2 device setup would charge me maybe 3 times worth the R28, I guess.
Not what I would call reasonable for "listen and mostly enjoy" my music.
I'm not an analyst nor hardcore "audiophile" (whatever that should be ^^)

The R28, like the Mojo 2, let me forget about the last bit of sizzling (pretending that's the detail I've been missing all the time) and make the soundwaves floating around me to get sunk into the flowing waves of the rhythm.

 

[Igor375375]

Wonder what dedicated devices out of the AGD line up could replace my R28 at a reasonable cost factor?

Hello. Not at a reasonable price. Real upgrade only on R-27 ( MK-2, RE, HE ). I think in the future to change.

 

[ethan60]

Fail upgrading the R28 firmware yet.
I've bought another Alrera USB... Same result. So it is not an hardware problem.
I've also used Quartus software 23.. Same result.
Altera usb is always detected... But it's not detected the JTAG chain with the Altera Cyclone IV FPGA of my Audio GD R28...
I claim support to forum in order to get suggestions to move on!!!
Maybe that drivers are installed, but wrong drivers to detect the JTAG chain with FPGA CHIP???
WHAT SHOULD I find in the the device setting under USB connection... ALTERA...???

Thanks in advance