Douk Audio U2Pro Digital Interface Upgrade is Being Planned and Waiting for Your Advice!

[Perpetual Novice]

Sorry to hear that, I can say this little piece of electronic engineering is what my system needed. I have gone through a few dacs over the years and always knew something was always just a little off with all of them. This has proved to be the elusive answer which leads me to believe there is a lot secrets in this field that are often kept.
Straightening those 0 and 1s up before they hit the dac is essential for good bass etc. I use a Windows PC for my source and an Fiio SR11 for when I am in need of a seat elsewhere.
Going to see if I can run the Fiio SR11 through it at some point and if I can then I just may get a better result with that too.

It has arrived and I've popped it in for a quick test run. A/B'd against the previous U2 pro XMOS XU208 (I don't have any measuring equipment). I preferred the new one, I was a little worried that I wouldn't hear any difference. LOL! To my ear, there was a definite bump in detail and sound stage, along with an increase in bass. At this point I feel like it was money well spent. I will do a proper listen at the weekend, hook it up in the office as well as the lounge and put it through its paces.

 

[Schlippwhip68]

It has arrived and I've popped it in for a quick test run. A/B'd against the previous U2 pro XMOS XU208 (I don't have any measuring equipment). I preferred the new one, I was a little worried that I wouldn't hear any difference. LOL! To my ear, there was a definite bump in detail and sound stage, along with an increase in bass. At this point I feel like it was money well spent. I will do a proper listen at the weekend, hook it up in the office as well as the lounge and put it through its paces.

Yes, good! I am not only pleased with what this little box has done with my Topping E50 but also my iFi Zen One Signature dac, which I was little surprised to find to be honest.
A far cleaner sound all round. Bass is round and bouncy which I like a lot, everything just has a more precise sound overall.

I am contemplating upgrading the clock in the near future but still unsure on which clock I am going to choose.
Either TXCO or Femto is not a problem. The problem is finding the correct size or at least how to apply a slightly smaller or larger size to the board as I have absolutely no experience at doing this.

The price for the Crystek 957 Femto here in the UK is reasonable imo. Finding a professional to do the job shouldn’t be to difficult either so I may be on a quest in a month or two.

I can safely say that between the laptop and the dac was my weakest link in the system and this little box confirmed my theory.
Very pleased with the results. It’s also far better performance than the almost equally priced Audioquest Jitterbug FMJ which does have a minor benefit to my system but not nearly as effectively as the U2 Pro (2025 Standard).

 

[somebodyelse]

I will do a proper listen at the weekend,

By 'proper' I hope you mean properly controlled (blind, statistically significant etc.) - otherwise you'll probably be fooling yourself.

 

[Roland68]

By 'proper' I hope you mean properly controlled (blind, statistically significant etc.) - otherwise you'll probably be fooling yourself.

You know, I think it's a lost cause.
The Douk Audio U2 PRO uses the XU316, with the necessary components to turn it into a DDC.
The circuitry and clock processing in current, high-quality DACs, such as Topping or SMSL, are significantly more complex. Even the SMSL D1, which costs €79, uses the same technology.
A USB interface built into a DAC would have to be absolutely terrible to produce a very small, but audible, difference. But those days are long gone, ever since the XU208, Amanero, and Xing Audio.

There's simply a lack of fundamental knowledge and understanding of how digital technology works. There would have to be a clearly measurable loss or alteration of data to produce an audible difference.

 

[Schlippwhip68]

You know, I think it's a lost cause.
The Douk Audio U2 PRO uses the XU316, with the necessary components to turn it into a DDC.
The circuitry and clock processing in current, high-quality DACs, such as Topping or SMSL, are significantly more complex. Even the SMSL D1, which costs €79, uses the same technology.
A USB interface built into a DAC would have to be absolutely terrible to produce a very small, but audible, difference. But those days are long gone, ever since the XU208, Amanero, and Xing Audio.

There's simply a lack of fundamental knowledge and understanding of how digital technology works. There would have to be a clearly measurable loss or alteration of data to produce an audible difference.

While I agree with you mostly you seem to be missing the point of the DDC’s position in the chain overall. It simply straightens the signal before it even reaches the dac which results in the dac having less work to do in the same given time frame which makes it far more efficient the difference is audible even on an £350 iFi Zen One.

I find it a familiar trait here where people seem to dismiss even basic common sense and nature when it comes to electronics.

 

[Roland68]

While I agree with you mostly you seem to be missing the point of the DDC’s position in the chain overall. It simply straightens the signal before it even reaches the dac which results in the dac having less work to do in the same given time frame which makes it far more efficient the difference is audible even on an £350 iFi Zen One.

I believe the opposite is true, and many people lack an understanding of a DDC, especially one as simple as the Douk Audio U2 PRO.
I studied DDCs and USB isolators (Intona) extensively years ago. Compared to the larger DDCs, the Douk Audio U2 PRO is very simple in its design.
Just take a look at common DACs with the XU316; it's very straightforward:
USB cable → XU316 interface with crystal → I2S transmission to the DAC chip.

The U2 Pro is nothing more than an externalized XMOS USB interface, as found in most modern DACs. The additional components only serve to convert the signal to SPDIF or I2S over LVDS and output it to the corresponding interfaces.
DDCs, including the U2 PRO, then result in the following signal path:
USB cable → XU316 interface with crystal → I2S → conversion to SPDIF (Toslink/Coax) or I2S over LVDS → external digital transmission to the DAC → conversion from SPDIF (Toslink/Coax) or I2S over LVDS to I2S → transmission to the DAC chip.

Where is the advantage in this? The U2 Pro contains exactly the same components as the DACs. It simply adds extra conversions, components, and external transmission, which in turn leads to more jitter that the DAC then has to compensate for.

I find it a familiar trait here where people seem to dismiss even basic common sense and nature when it comes to electronics.

I (and presumably not only I) would like to hear that.

 

[Schlippwhip68]

I believe the opposite is true, and many people lack an understanding of a DDC, especially one as simple as the Douk Audio U2 PRO.
I studied DDCs and USB isolators (Intona) extensively years ago. Compared to the larger DDCs, the Douk Audio U2 PRO is very simple in its design.
Just take a look at common DACs with the XU316; it's very straightforward:
USB cable → XU316 interface with crystal → I2S transmission to the DAC chip.

The U2 Pro is nothing more than an externalized XMOS USB interface, as found in most modern DACs. The additional components only serve to convert the signal to SPDIF or I2S over LVDS and output it to the corresponding interfaces.
DDCs, including the U2 PRO, then result in the following signal path:
USB cable → XU316 interface with crystal → I2S → conversion to SPDIF (Toslink/Coax) or I2S over LVDS → external digital transmission to the DAC → conversion from SPDIF (Toslink/Coax) or I2S over LVDS to I2S → transmission to the DAC chip.

Where is the advantage in this? The U2 Pro contains exactly the same components as the DACs. It simply adds extra conversions, components, and external transmission, which in turn leads to more jitter that the DAC then has to compensate for.


I (and presumably not only I) would like to hear that.

Thankyou for your opinion and methodology. The end result in my system using something that I have the ease of returning if I find no improvement is one that has caused me to miss a meal or two. If I need to lose weight all I have to do is use my ears at the moment.

 

[somebodyelse]

I find it a familiar trait here where people seem to dismiss even basic common sense and nature when it comes to electronics.

A number of aspects of electronics, and dynamic systems in general, don't behave according to most peoples' idea of "basic common sense and nature." Ask a bunch of engineering undergraduates how easy it was to get to grips with control theory for example. A lot of HiFi marketing exploits this by making claims that appeal to "common sense" to sell things that don't actually do what they claim, coupled with expectation bias and a lack of properly controlled listening that makes people think they hear an improvement. Those who have put in the effort to understand how these things actually work will dismiss these for the BS they are.

 

[Perpetual Novice]

Yes, good! I am not only pleased with what this little box has done with my Topping E50 but also my iFi Zen One Signature dac, which I was little surprised to find to be honest.
A far cleaner sound all round. Bass is round and bouncy which I like a lot, everything just has a more precise sound overall.

I am contemplating upgrading the clock in the near future but still unsure on which clock I am going to choose.
Either TXCO or Femto is not a problem. The problem is finding the correct size or at least how to apply a slightly smaller or larger size to the board as I have absolutely no experience at doing this.

The price for the Crystek 957 Femto here in the UK is reasonable imo. Finding a professional to do the job shouldn’t be to difficult either so I may be on a quest in a month or two.

I can safely say that between the laptop and the dac was my weakest link in the system and this little box confirmed my theory.
Very pleased with the results. It’s also far better performance than the almost equally priced Audioquest Jitterbug FMJ which does have a minor benefit to my system but not nearly as effectively as the U2 Pro (2025 Standard).

I've found that Douk Audio's chat on the official website has been pretty helpful. You could always shoot a few questions their way.
Either way, I'm quite happy with my purchase, we seemed to have scored.

Very interested to see/read Amir's review, as Douk Audio mentioned that they sent it his way.

 

[Perpetual Novice]

By 'proper' I hope you mean properly controlled (blind, statistically significant etc.) - otherwise you'll probably be fooling yourself.

Thanks!

 

[Schlippwhip68]

I am looking at this at the moment…..

I just found this on AliExpress: ￡81.99 | 22.5792MHz 24.576Mhz MUSETEC custom clock upgrade Crystek 957

https://a.aliexpress.com/_EJutnfe

 

[Schlippwhip68]

Does anybody know the size of the square on the board which the CO sits? I am looking at a 20x14mm replacement….

 

[somebodyelse]

Does anybody know the size of the square on the board which the CO sits? I am looking at a 20x14mm replacement….

Scale it from the photo using known dimensions as reference - something like the 0.1" pin spacing from J8 or one of the other leg spacings.

 

[Schlippwhip68]

I could use an ‘U2 Pro XL’ version of this unit very easily. With the XL version I would allow for twin coaxial, twin optical out, single USB C out and a separated USB C power port from the USB C in. Output selector/uni-mode(?).

 

[Schlippwhip68]

Ok looking at the replacement clock again. Ed of Old Guy Hifi reached out to Douk and retrieved some details:

To replace the U2 Pro's oscillator, it needs to meet these specs:
24.000MHz / 1.8V (active oscillator)
Can be SMD or through-hole (DIP)
SMD size: 5032
DIP spec: DIP14
Other than meeting those specs and size, the smaller the frequency tolerance (*ppm), the better. Choosing a high-precision TCXO would give a more noticeable improvement.

I just found this on AliExpress: ￡21.79 | Gold Plated TCXO DIP-14 1M 8/10/16/20/24/25/30/32/40/48/60/100MHZ Golden Rectangular Temperature Compensated Crystal Oscillator

https://a.aliexpress.com/_EwtUSbE

I maybe missing something here but I am struggling to find an TXCO @ 24mhz with an 1.8v. The ones I found start at 3.3v - 5v.

 

[Schlippwhip68]

So, it turns out that the 1.8v is an outdated structure which explains the needle in the haystack as far as finding one.
Regardless to say the standard stock version has brought an improvement to my system already so I am going to give up the chase here. It’s sound good already.

I will say it’s shrewd business on behalf of Douk Audio and cool to see the company reinvesting in the upgrading of this product and looking forward to the TXCO version when it’s released.

I am enjoying Douk Audio very much this year. Thier A5 amplifier is big hit here at my house and I am using it this morning to feed a pair of Q Acoustics 5020 speakers. I messed around with the op amps and those 5020’s really like the opa1656 in the A5. It works and works well beyond expectations. A really good match.
Douk’s new P7 pre amp looks very good too and will look at that later this year.

That A5 amp design is game changer imo. Switching op amps is forward thinking, good for the pocket too!

Maybe an A5 with true XLR balanced input would be even better…I don’t think I am going out on a limb to say that it probably most certainly would.

I just find less need for a pre amp with the A5. It sounds a little more musical than my other options to, don’t ask me to explain that and I know I am not the only person whom found that with the A5.

 

[Schlippwhip68]

Ok, so a friend on ASR directed me to this. Someone has upgraded the U2 pro with an 3.3v - 5v TXCO Clock. I reached out to Douk Audio already and was told the working voltage of the clock in stock form is 1.8v. So we have an increase of 1.5v with the new clock on this board.

What do you think ASR/Douk Audio is this a safe board?

While currently it’s advertised that the unit can be upgraded I think it is very important and needs to be clarified asap as there is no information on Douk Audio website regarding exactly what is needed for the upgrade.

Can this lead to endangering life and a problem with the law which in turn makes Douk Audio liable if things go wrong?

 

[somebodyelse]

This can lead to endangering life and a problem with the law which in turn makes Douk Audio liable if things go wrong.

I can't see how Douk would be liable for anything but false advertising, let alone how a consumer DDC with no mains power could endanger life.

 

[Roland68]

Ok, so a friend on ASR directed me to this. Someone has upgraded the U2 pro with an 3.3v - 5v TXCO Clock. I reached out to Douk Audio already and was told the working voltage of the clock in stock form is 1.8v. So we have an increase of 1.5v with the new clock on this board.

What do you think ASR/Douk Audio is this a safe board?

While currently it’s advertised that the unit can be upgraded I think it is very important and needs to be clarified asap as there is no information on Douk Audio website regarding exactly what is needed for the upgrade.

This can lead to endangering life and a problem with the law which in turn makes Douk Audio liable if things go wrong.

View attachment 492962

I also find it absolutely ridiculous that a device operating at 5 volts and a maximum power of 2.5 watts could in any way endanger a person's life.
Es gibt zig millionen, oder sogar über eine milliarde geräte auf der Welt die mit USB 2.0 betrieben werden, und das seit 25 jahren, aber von so etwas habe ich noch nie gehört.

Furthermore, it's clearly a DIY project; learn and take responsibility if you're going to do it.
The moment you open a device and modify something, you alone are responsible for it, and no one else.

 

[Schlippwhip68]

I can't see how Douk would be liable for anything but false advertising, let alone how a consumer DDC with no mains power could endanger life.

I wouldn’t like to see Douk liable either but it’s a technicality that should be addressed in the advertising sooner rather than later.