New Audio-gd R-7, R-7HE R-8, R-27, R-27HE, R-28 Flagship Resistor Ladder DACs and DAC/amps

[Presence]

Has anyone done a DIY with parts from audio-gd?

I see DA boards can be purchased.

Im dreaming of a really small dac with dc input.

Not sure this is what you had in mind.... but I'll offer my R8HE mod experience which may temper your actions [or not!]
I hope my data points are useful to you in some way.

When I saw the DA-7 MKI DAC boards for sale about two months ago[?] I inquired about the possibility of adding them in parallel in my 2019 R8HE.
I wanted to buy three pair to go with the existing 2019 DA-7 DAC boards to make a 4 DAC per-channel R8.
For reference, I read everything I could on DIY parallel DAC projects - one concluding that after the second DAC there were diminishing returns, a second perspective concluding that resolution continues to improve with more DACs. The kicker for me was an MSB owner saying he sold his Select DAC for a Reference, then went to the Premier electing to put his money on the best source - after getting a Taiko Extreme, he no longer missed the more expensive MSB DACs... FWIW.

Two boards will fit stacked in the existing 2019 R8HE chassis. If I reduced the height of the standoffs at the bottom of the chassis in the R8 I would be able to fit four of them stacked.
Immediately after my request/inquiry to AGD, the URL sell sheet for the DA-7 MKI was taken down.
But as with adding R8 master clock input, I persisted and eventually received an answer....
but with signature from another AGD employee, not Kingwa, and it was not a positive experience thereafter due to poor communication and lack of reliable follow-through.
So AGD would sell me the boards under the hypothetical that they had never tried it but thought in theory it should work and I assumed full responsibility. OK fine...
My December 2019 R8HE I believe was at the end of the 92 piece resistor ladder DA-7 board production where the 140 piece resistor ladder MKI DAC board came to be.
So I decided not to go with four per-channel all at once and ordered two pair for two MKI DAC boards in parallel per-channel.
Some of the minutia I had to wade through on my own was
- at what point do both the digital and analog PSs run out of current when adding additional DA-7 MKI boards? I suspect the answer is two but I don't know.
- how many DA-7 boards would the Data, BCK and WCK feeds off the FPGA work with without buffering?
- what would the effect of the ACSS circuit have being fed double the current with each doubling of boards?

Fast forward to getting them to work -
After requesting the modules to be used as explained above I was shipped the CPLD FW version for direct IIS input and not what was needed - to accommodate the signals coming from the FPGA.
So then I had to buy a $37 Blaster specific for the CPLD flash.
After learning that I needed the blaster, I used the ten days waiting for the blaster shipped from China to try to connect the MKI directly to IIS [as supposedly shipped] but I was unsuccessful.
It took about 5 hours to eventually figure out how to get the .jed file from Windows to the Oracle Virtual Box used to run the CPLD Blaster from my laptop.
If you do this for a standalone DIY DAC fed directly by IIS, you will [hopefully] not need to do this...
It worked but the channels on the MKI played out of phase. I mimicked the solder pad options found on my original DA-7 and the MKI boards then worked as they should.
Turns out that the solder pad options on the newly shipped MKI boards were configured for the R7 which per AGD, are configured out of phase to work on that platform.
After about an hour of warm up, it was clear that the level of inner detail and calm ease upgrading to a single DA-7MKI was easily distinguishable. I did not hear any improvement for DSD however.

Adding the second MKI in parallel immediately added further detail and ease but having to wait another 100 hours for the second MKI board to settle in makes reliable long term comparison between one and two DAC boards unreliable.
After adding the second DAC board, one of the channels was introducing static over the music when playing DSD. All PCM up to 384K played fine.
I suspect that with the higher DSD speeds, the data from IIS inputs from the FPGA may be at fault from impedance loading from two sets of boards.
I'm waiting on some SMD breakout boards to add signal buffers to isolate/regenerate each of the IIS data lines from the FPGA to see if that fixes it.
I feel confident that it will.
In the mean time, for a functional solution, I can transcode DSD to PCM 352.8 in Roon although I don't listen to DSD other than to compare to their hi-res PCM versions.


This is a work in progress and I have additional work ahead. Based on the poor communication flow I've decided not to purchase the additional DAC boards.
I am quite happy with the jump in improvement both from the legacy DA-7 and to two paralleled MKI versions.

Rich

Supplemental: After references to "fast power supplies" from Antipodes Audio and having experienced Server/Player LPS to Hybrid LPS/SMPS factory upgrade improvements along with utilizing the Ferrum Hypsos to replace the LPS in my SingXer SU-2 DDI [also producing very notable SQ improvements], I used the Hypsos to supply 5V to the digital section of the R8 and found a notible resolution improvement in SQ. The Antipodes and the Hypsos are using DC-DC converters after the bridge rectifer. Again, FWIW...

 

[Currawong]

Im dreaming of a really small dac with dc input.

Get a Cayin RU-6 with a cable to split off USB power.

 

[OCC7N]

Get a Cayin RU-6 with a cable to split off USB power.

Thanks! My mission is to build the smallest “desktop” R2R system as possible. It does not need to be with battery.

DC inputs(5/12V) preferred.

So far I have:
DDC: Ideon 3R Renaissance mk2
PSU: iFi iPower X 9V for DDC
USB: FIBBR ALPHA cable

I need a powerful but small amp. Centrance Ampersand can still function in desktop mode, even if battery fails. Im probably going to order it as it has the power I need for portable desktop.

Any smallest R2R dac with dc input you know of?
-no dongles

 

[gimmeheadroom]

My mid-priced Hiby RS2 is NOS R2R and has a USB-C -> Coax cable included in the package.

It has two running modes with respect to power- one where it takes power over USB. It has the option when it runs as an MQA USB DAC either to take power from the USB source or not. Apparently this is something a lot of people want and not many DAPs have it.

 

[OCC7N]

An unfair battle between two dacs on two different configurations!

In October I will hopefully, put up an interesting challange between R-1 NOS(magnahifi link) vs R8HEmk2. Source(PC and Pink Faun UB V2) is the same but there are some differences in hardware. R1 will have no time to prepare for the fight, however the fight will have have more rounds than usual...

R8HEmk2
LHY OCK-2
DI20HE
No Software advantages.
ACSS to amp

vs

R-1 NOS
USB reclocker
Cable: Optical and silver usb cables. Comparisons.
All software advantages(HQplayer, DSP Processing etc.)
ACSS to amp

-

Improving Delta-sigma(ds) dac experience, also R2R, but not in the same way.

When it comes to sound on pc, Pink Faun USB Bridge V2 does something that I actually thought was the DI20HE doing it - the air, the ether. I tested this on a small ds dac from a known company, that actually makes very good dacs, but not this one, on a regular USB port.

Connecting the ds dac straight to the motherboard, sounded worse than my Dell laptop soundcard(even a reclocker helped but...). Its just a very bad dac at this point(200hours burnin)

However when I connected it to the Pink Faun USB Bridge V2- I got goosebumps straight away(after one day of connection/warmup) and recognized some of the sound characters I got from AGD system. It was the breeze, the pulse to the music. It turned the poor ds dac into something much better for my experience. The notes of instruments, became more visible in depth! and less ds harsh/compressed! - I can normally not keep turning the volume up on ds, but with PF I can!

PF character + DI20HE separations, I know the R-1 NOS won´t have a chance. Also the new OS mode(NO) in the R8HEmk2 is something special for me, less chip sound, more algorithmic sound.

This combo is made for each other, as I see the DI20HE take advantage, adding more separation to the soul of PF.

-

This leads to my scepticism of optical cables(and their clocks), even the one I´m waiting on from FIBBR, thats true optical on the source side and copper on the DAC side. Every optical cables and solutions I have tried locked the music, took away its pulse, breath and soul, but delivered performing high resolutions = blacker background, but rhythmicly reminded me static one layered experience

When I had the small USB reclocker after the pink faun the sound was locked it was not moving like a "R2R" experience. DI20HE did not lock the sound like the other small reclocker I used.

-

There is a deltasigma black background, and there is a audio-gd R2R black background. To get to the audio-gd black background: the first challange is to remove the *mushy sound some of the owners have talked about in this thread. I don´t know how it´s done on other systems but after Corsair AX1600i + PF UB V2 was added, it was like a total different system, not kidding!

It´s not just a black background - it´s a stage where every element has its own layer/background, playing freely/3D. The empty spaces, is so physical. Organically immersive without being charming.

-
When I´m asked how does audio-gd sound. My answer is, it sounds like nothing, it´s not there. It´s just you and the music.

-
*I believe audio-gd has less digital power tweaks to eliminate noise, which will result in revelations of noise in the source. Pairing the right power tweak is the journey within itself.

 

[bodiebill2]

@OCC7N
Having recently ogled the R-1 NOS, and owning an R8HE Mk2, I am looking forward to the comparsion...
I read somewhere that -- in spite of the name -- the R-1 NOS can also do its own OS?

 

[OCC7N]

@OCC7N
Having recently ogled the R-1 NOS, and owning an R8HE Mk2, I am looking forward to the comparsion...
I read somewhere that -- in spite of the name -- the R-1 NOS can also do its own OS?

Thanks! It only has NOS(reading the manual) - The reason besides better DA board than R1, I also chose it is because NOS compatibility with HQplayer when upsampling, not that R8s can not do it, they can in N1 mode. I read that the R1NOS may have another version of NOS, not sure:


"Some people love the sound of the pure NOS mode , so we design the R-1 NOS that optimize the pure NOS mode , offer the pure musical sound .
The NOS design don't need the main clock signal for working, that is the advantage of the NOS design to avoid the effect by the main clock's jitter "

This is very interesting!

 

[FredA]

Thanks! It only has NOS(reading the manual) - The reason besides better DA board than R1, I also chose it is because NOS compatibility with HQplayer when upsampling, not that R8s can not do it, they can in N1 mode. I read that the R1NOS may have another version of NOS, not sure:


"Some people love the sound of the pure NOS mode , so we design the R-1 NOS that optimize the pure NOS mode , offer the pure musical sound .
The NOS design don't need the main clock signal for working, that is the advantage of the NOS design to avoid the effect by the main clock's jitter "

This is very interesting!

Should give the same sound as the r2r 11,only more resolved and refined. I am pretty sure you will like it. Very musical.

 

[bodiebill2]

Thanks! It only has NOS(reading the manual) - The reason besides better DA board than R1, I also chose it is because NOS compatibility with HQplayer when upsampling, not that R8s can not do it, they can in N1 mode. I read that the R1NOS may have another version of NOS, not sure:


"Some people love the sound of the pure NOS mode , so we design the R-1 NOS that optimize the pure NOS mode , offer the pure musical sound .
The NOS design don't need the main clock signal for working, that is the advantage of the NOS design to avoid the effect by the main clock's jitter "

This is very interesting!

Is it different from this one?
https://alpha-audio.net/review/multitest-the-best-dac-for-1000-euros/2/
That is where I got the OS idea.

 

[OCC7N]

Is it different from this one?
https://alpha-audio.net/review/multitest-the-best-dac-for-1000-euros/2/
That is where I got the OS idea.

Yes R1 with the older DA boards

 

[FredA]

Yes R1 with the older DA boards

I suspect that the measurements part caused a bias. Should have been done after the listening tests. Kingwa adds distorsion on purpose.

 

[OCC7N]

I suspect that the measurements part caused a bias. Should have been done after the listening tests. Kingwa adds distorsion on purpose.

That reminds of an audiophile quote of something like "...finding the perfect distortion profile"

Which I think is also the reason for the black background and separations feel more textured/physical

 

[FredA]

For those who are looking for a inexpensive streamer (pi-based) with 10mhz clock input and who are quite knowledgeable in that sort of Linux-compatible platform, i found this nice little unit on ali.

https://fr.aliexpress.com/item/1005005549410657.html

I was able to set it up after struggling for about 8 hours.

First, I wanted to install Volumio, but which required to take the top off to replace the microsd card. Took 30min. The cover is very tightly fit and screwed from the bottom. Had to push very hard with a small screwdriver through the holes.

The streamer came with Roopi as sw. It booted without issue with but it did not with Volumio 2.9. Had to install the latest Volumio 3. I ran into an issue with the usb audio out not working. Following the seller's advice, I had to use ssh and nano to edit the /boot/userconfig.txt and add this line to it:

dtoverlay=dwc2,dr_mode=host

Afterward, had to mount a remote disk to have access to music files, the streamer does not have aux usb ports. And i was set to go, or almost.

I found out that the 5.5/2.1 connector had a center shaft smaller than normal so the connection was rather loose. I used the cable on the included walwart to make an adapter... (plus I used another adapter that had the female part). That fixed the issue.

I did not mention: the 10mhz input is 50-ohm. I am in the process of converting it to 75ohm. This requires soldering a 75ohm across the unused ocxo pads on the board and replacing the bnc plugs and cable inside with 75-ones. I could not find any cable that fit the required spec (ipex ipx on the board side and 75bnc female on the other side). So I will use use a 15cm 75-ohm female bnc to mmcx male and a 5-cm 50ohm mmcx female to ipex ipx cable. The mismatch being close to the 75ohm resistance, it should be of little importance. I am currently using the original hardware (except the 75-ohm resistor I added) with my clock's 75ohm out and a 75ohm oyaide cable to feed the clock, without any issue.

Fo those who want to use the thing as is with the 50-ohm input, i recommend to solder a 50ohm resistor across the ocxo input pads if to use a square wave. Sine waves will work optimally without this.

And about sound quaity? So far so good. Still burning the thing but I think it beats the usbridge sig.

 

[Jandu]

For those who are looking for a inexpensive streamer (pi-based) with 10mhz clock input and who are quite knowledgeable in that sort of Linux-compatible platform, i found this nice little unit on ali.

https://fr.aliexpress.com/item/1005005549410657.html

......

I found out that the 5.5/2.1 connector had a center shaft smaller than normal so the connection was rather loose. I used the cable on the included walwart to make an adapter... (plus I used another adapter that had the female part). That fixed the issue.
.....

And about sound quaity? So far so good. Still burning the thing but I think it beats the usbridge sig.

A couple questions:

1, It is a DC 6V power input, not a 5V, as shown on one of the pictures.
2, Do you have any idea how the A version compares to the B version.
3, Ever tried to compare sound quality between Moode, Volumio and PiCoreplayer.

Thanks

 

[FredA]

A couple questions:

1, It is a DC 6V power input, not a 5V, as shown on one of the pictures.
2, Do you have any idea how the A version compares to the B version.
3, Ever tried to compare sound quality between Moode, Volumio and PiCoreplayer.

Thanks

1. 6V. Some psu, like my zerozone can be adjusted from 5 to 6.
2. No. Synching the streamer with the rest is a good idea though (di20he and he7 mkii).
3. Only moode with the usbrdige. Moode sound perhaps better but the UI sucks.