Massdrop x Airist Audio R-2R DAC: A Discrete Resistor Ladder DAC For $350
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With all the prototyping work, since it is now "released" on massdrop is there any big reason as to why the drop will ship in 6 months time at the earliest rather than sooner?

Besides that, there will not be any costs cut between the prototype (looking at all the raving positive reviews of the review units), right? The 'Hibiki' author made the following comment on the massdrop Discussion page:

[about components on the current PCB design on the massdrop page...] 6656 using here is not suitable for ladder because it produce 50uvrms noise, while my design(6654) can go deep to 1uvpp that make the sound purer, darker. This should be a costdown point for Airist. 6654/6656 share the same footprint. It is simply a costdown(probably from 3 USD to 2USD), but 350 times noisier.

For the record I don't want to come across as too sceptical or anything, I have my pre-order for the R2R placed, it's rather out of concern of receiving the same quality unit as is spoken of in the preview/reviews on the massdrop description page and here on head-fi. It would not be the first time a prototype unit is of higher quality than the final mass production units.

Also, I doubt the THD spec.
How about to post FFT result, let customer see if it is that low level.
Once using that noisy power source, it is really difficult to achieve -118dB SNR. For my design, it can go deep to -140db@1k further(fully tested). Just one bulk more.
 
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Baten

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Also, I doubt the THD spec.
How about to post FFT result, let customer see if it is that low level.
Once using that noisy power source, it is really difficult to achieve -118dB SNR. For my design, it can go deep to -140db@1k further(fully tested). Just one bulk more.
That's good specs. One bulk more ?
 
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CJG888

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Is it available on Taobao?
Yes, you can find that. However, I dont recommend to use tht old one. We developed balanced version with much faster firmware(PCM32x) installed, will release this August in Hongkong Exhibition.
 
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Will this be a board or a finished DAC with case and PSU?

The idea of a balanced output looks interesting...

Will it take a direct I2S input (from my modified Shinrico D3S)?
 
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Got that. Thank you very much. To be honest, I got the same result using QA400. But becareful, using 0.1%resistor could worse 10db at least. I presume that they are using 0.05% the same as.
 
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Yes, you can find that. However, I dont recommend to use tht old one. We developed balanced version with much faster firmware(PCM32x) installed, will release this August in Hongkong Exhibition.
I'll be in Hong Kong around that time. What's the name of the expo and the dates? Would love to go take a look.
 
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randytsuch

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My opinion, FWIW, layout is obviously a copy. They even used the same connectors, and located them in the same places. I can't believe this was by coincidence.
Only way to know about the trace routing is if both companies provided the routing, and someone compared them. Would be easy enough to do.

And in the end, afaik, Soekris came up with the general idea first, and others have copied his idea of using a FPGA to feed shift registers tied to precision resistors to generate the output waveform. People copy ideas all the time though, no laws against that.

But, I always thought the real magic and the most important IP for this type of DAC was in the FPGA. I would expect companies to lock the FPGAs, so you can't read what's inside, and so you can't steal this IP.

Would also be really interesting to see if anyone gets both, and compares the sound.

Also, would be great if the board was sold on Aliexpress, opens it up the DIYers who want to experiment with it.

Randy
 
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My opinion, FWIW, layout is obviously a copy. They even used the same connectors, and located them in the same places. I can't believe this was by coincidence.
Only way to know about the trace routing is if both companies provided the routing, and someone compared them. Would be easy enough to do.

And in the end, afaik, Soekris came up with the general idea first, and others have copied his idea of using a FPGA to feed shift registers tied to precision resistors to generate the output waveform. People copy ideas all the time though, no laws against that.

But, I always thought the real magic and the most important IP for this type of DAC was in the FPGA. I would expect companies to lock the FPGAs, so you can't read what's inside, and so you can't steal this IP.

Would also be really interesting to see if anyone gets both, and compares the sound.

Also, would be great if the board was sold on Aliexpress, opens it up the DIYers who want to experiment with it.

Randy

Some of my customer have done so much expriment on it, says Li-on power supply, direct transformer output bypassing opamps, insanely pricy silver foils capacitor, metal-can OpAmps, LPF alterations, reclokings, better isolations....so much creative ideas. All of them are enjoying DIY.
That exactly is the scene we want to see.
 
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My opinion, FWIW, layout is obviously a copy. They even used the same connectors, and located them in the same places. I can't believe this was by coincidence.
Only way to know about the trace routing is if both companies provided the routing, and someone compared them. Would be easy enough to do.

And in the end, afaik, Soekris came up with the general idea first, and others have copied his idea of using a FPGA to feed shift registers tied to precision resistors to generate the output waveform. People copy ideas all the time though, no laws against that.

But, I always thought the real magic and the most important IP for this type of DAC was in the FPGA. I would expect companies to lock the FPGAs, so you can't read what's inside, and so you can't steal this IP.

Would also be really interesting to see if anyone gets both, and compares the sound.

Also, would be great if the board was sold on Aliexpress, opens it up the DIYers who want to experiment with it.

Randy
I might be wrong, but I was under the impression that the connectors were not located in the same places. Someone can correct me.
 

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randytsuch

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sosolar
If there was an english website, either ebay or ali that had your modules, I think it would open it up to a lot more diy'ers

SamusAran
Looking at the pic here
https://www.massdrop.com/buy/massdrop-x-airist-audio-r-2r-dac/talk/2099406?irgwc=1&clickid=UUeQsxzt503WRx9ReFUyDz6FUkjR9ZU22zTU0w0&utm_term=385697&utm_content=VigLink&utm_medium=affiliate&utm_source=impactradius#imagecarousel

Comparing the black board on far left to the hibiki red board, connectors look the same. The spacing between connectors is slightly different though.
Now I wonder if the pinouts are the same?
 
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June 7 update (relative to my original post #3 in this thread):
OK, so I had the opportunity to spend more time with the RDAC, get a high-quality switcher for better A/B with other amps, so following are my impressions.

Initially, I theorized the volume is higher from the RDAC compared with my Metrum Amethyst DAC. It has been confirmed that RDAC outputs 2.5V whereas the Amethyst is outputing 2.0V
I wanted to further verify those spec numbers, so using my iPhone 6S with SPL meter app, Sennheiser HD600 headphones and a 1KHz tone playing... I confirmed that when RDAC fed the amp - the volume level was almost exactly 2dB louder. Tried various listening levels and the 2dB was pretty consistent. Introducing a passive preamp between RDAC out and amp input, volume knob max'd - the volume dropped by 2.5dB. So now, difference between 2 DACs is 0.5dB (this time, the Amethyst is the louder one, but only by 0.5dB).

Now, that I have a more even field signal levels feeding my A/B switch, I was ready to repeat my comparisons.

Let me recap my 2-DAC setup:
1. Mac mini -> USB cable -> Gustard U12 -> Coax cable -> Metrum Amethyst -> A/B switcher -> amp
2. Mac mini -> USB cable -> Gustard U12 -> SPDIF (optical) cable -> RDAC -> passive preamp (to lower voltage) -> A/B switcher -> amp

The bold components are shared between 2 audio paths.

This time around, I have used Massdrop's LCX and CTH amps, as well as the Schiit Lyr3 (with stock Tung Sol tube).
I have used both the HD600 headphones as before, but also Mr. Speakers AEON Flow Closed.

After spending several hours, listening to MANY tracks from various genres (but mostly Rock, Pop Rock, Heavy Rock, Metal) here are my observations:
a. In most tracks I could NOT hear any difference at all. Switching back and forth (using the A/B switch, mid-song) I could not even tell the DAC was switched..... Just identical.
b. In very few tracks, the male and female vocals sounded tiny bit different. I thought the Amethyst might be a tiny bit more detailed? or maybe better dynamic range? Again, VERY small difference. Would never have heard it if not A/B during playback with a switch that takes zero time to change source.
c. In other very few tracks, the RDAC sounded a tiny bit better. Trying to describe it I would say maybe the whole presentation felt like fuller / thicker sound. So for those very few tracks I would give the tiny edge to the RDAC.

I must caveat that my hearing is good but I do NOT have golden ears, and I was never musically trained. So others with better hearing or golden ears might hear things I do not.

MY conclusions:
1. Both DACs sounded great! Very natural and musical. Not dry or analytical. Both made me want to keep listening to the music :)
2. Those observations did not change much switching between amps and headphones. So, I do not think it is a synergy thing, but a real (tiny) difference.
3. Knowing the sound difference is almost non-existant, and knowing the price difference is 3x between those DACs - I have no problem saying that:
If I were in the market today for a DAC, with a budget of $1000 - I would absolutely buy the RDAC!
(and it absolutely is worth the 6 months wait)
 
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maximus69

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Hey Everyone,

This is a week that I was looking forward to for a long time. Finally, the release of the RDAC!

It’s not easy to hold back when people keep asking about the matching DAC. :wink: But, this project has taken longer than we anticipated (for different reasons, including getting the power supply to a high level) and so it has been best to ensure we had the samples in-hand so you could read several impressions on day one. I’m not only happy that we finally have it available and out of the bag, but I really like the sound and presentation.

Monday, I snuck in a couple songs with a new HD 58X sample that I have.
RDAC > CTH > HD 58X
I am confident that many will be very happy with this and other combinations.

People around me or that helped provide feedback for prototypes know how much I have waited for this week…

We had early prototypes kicking around in 2016 that I passed around and Airist steadily made changes to every aspect of the design over the time period I have been working with them.

Since we have more questions about the origin right now than the evolved result, everyone is retracing the first steps to the design and the references used. We should have even more to share. Also, we need to know more about the Hibiki design and we don’t read Chinese. We are getting some help with that to fully understand the differences between the designs. (The only thing similar right now is the way the simplest part of the circuit, the ladders, and top PCB parts are laid out. Were they both working from similar references or are these totally different designs?)

While we wanted to answer enough questions about sound (through review samples) and about the design & value (so you could make a purchasing decision), we have also been trying something new in Audiophile: a Q&A perk for launch purchasers. There is some secret sauce in areas of the design which are now important to highlight early due to questions about design differences and origin. William Tse is also an International Man of Mystery right now and we thought we had a whole month to figure out what we could share about him. He’s much more interesting than his (partial) academic bio that we have seen on the Airist site. The best way to describe him is not really engineer...scientific researcher? Yeah, that probably. So, there will be more Q&A before we even get to the “perk”. (We may have to figure out something else fun and special for that perk after we’ve satisfied everyone’s current curiosity.)

This launch feels a bit like how I FINALLY proposed to the love of my life this past weekend. I had all these awesome ideas for getting her to meet me in France, such as when I “have to visit Focal...come meet me!” Or, I was going to propose to her in Hawaii next week on our family trip. In the end, I needed to spill the beans early because she couldn’t understand why I was pushing her to do something and she was getting mad at me. In some ways, I spoiled the surprise...but in other ways I did what I should have already done and it turned everything around.

Been working across time-zones and continents the past couple of days/nights. Things are always slower than we like. Thanks for being interested, caring about the little guy, giving this DAC a chance, and for your patience as we unravel mysteries and share what we find as soon as we can.

Best Always,
Christian
Thanks for update...i am looking forward to watching things unfold
 
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