Douk Audio U2 Pro DDC - Poorman DDC for an affordable & clean digital signal
Oct 29, 2022 at 3:07 PM Post #361 of 583
I was curious about the upgraded clock options, so I recently acquired a DDC with TCXO oscillators. Its relatively cheaper than the Douk with TCXO.
https://www.aliexpress.us/item/3256...2pIv1lr&gatewayAdapt=glo2usa&_randl_shipto=US

The difference with the Douk with standard oscillators is significant. More details, bass texture, better reverb. If my non-musician ears can sense the differences, then I would say, upgrading the clock is worth it, if the DAC is resolving enough. I have now ordered a Douk/Leaf audio with femtosecond clock. Aliexpress was selling it significantly cheaper than Ebay, so I grabbed one. Since I will have both the original and upgraded versions, I will compare between the two, once it arrives.
https://www.aliexpress.us/item/3256...2pIv1lr&gatewayAdapt=glo2usa&_randl_shipto=US
I must say, it is better quality product that Douk / Leaf Audio U2 Pro. It has four layers PCB vs. two layers. Two layers board has no chance equalising ground noise to the same level.

They also claim of using original Murata transformer and quality regulators. If it is true, U2 Pro has no chance in my opinion. Crystek oscilators (esp. CCHD-575) are sensitive to the PSU noise and in my opinion the U2Pro suffer from poor regulation. On-board regulators are also dangerous, as a destructive voltage is only 7V.

U2 Pro is more functional, having an option for external power supply. If you use with a noisy USB host it will benefit from redirecting ground loops, otherwise there is a little chance. But I waiting for your verdict, sorry to disappoint.
 
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Oct 29, 2022 at 3:21 PM Post #362 of 583
I must say, it is better quality product that Douk / Leaf Audio U2 Pro. It has four layers PCB vs. two layers. Two layers board has no chance equalising ground noise to the same level.

They also claim of using original Murata transformer and quality regulators. If it is true, U2 Pro has no chance in my opinion. Crystek oscilators (esp. CCHD-575) are sensitive to the PSU noise and in my opinion the U2Pro suffer from poor regulation. On-board regulators are also dangerous, as a destructive voltage is only 7V.

U2 Pro is more functional, having an option for external power supply. If you use with a noisy USB host it will benefit from redirecting ground loops, otherwise there is a little chance. But I waiting for your verdict, sorry to disappoint.

Thank you for your insightful feedback (and previous posts in this thread, which are all very helpful). The point about damage risk from higher external voltage is a valuable point. I will be more careful with the Douk when using external PSU. Currently, I feed it from a battery pack that supplies 5.5 V.

One caveat with the older TXCO DDS, it does not support DSD through coax, only I2S is supported, whereas Douk supports DSD64 through coax. Minor issue, but worth mentioning I think. Also, it takes ~20 sec from connecting USB to start playing music, whereas with the Douk, its almost instantaneous.
 
Oct 29, 2022 at 4:04 PM Post #363 of 583
Thank you for your insightful feedback (and previous posts in this thread, which are all very helpful). The point about damage risk from higher external voltage is a valuable point. I will be more careful with the Douk when using external PSU. Currently, I feed it from a battery pack that supplies 5.5 V.

One caveat with the older TXCO DDS, it does not support DSD through coax, only I2S is supported, whereas Douk supports DSD64 through coax. Minor issue, but worth mentioning I think. Also, it takes ~20 sec from connecting USB to start playing music, whereas with the Douk, its almost instantaneous.

Probably anything over DSD64 (which is actually 99.9% of all DSD in the world) won't work very well over coax in many applications so this is kinda ok.
 
Oct 29, 2022 at 4:22 PM Post #364 of 583
Probably anything over DSD64 (which is actually 99.9% of all DSD in the world) won't work very well over coax in many applications so this is kinda ok.

I agree. Douk does DSD64 over coax, which is fine with me. The other DDS (with TCXO oscillators) doesn't do any DSD over coax, which is fine too in a sense, since downsampling to 192K makes not much of a difference to me sonically.
 
Oct 29, 2022 at 4:27 PM Post #365 of 583
I agree. Douk does DSD64 over coax, which is fine with me. The other DDS (with TCXO oscillators) doesn't do any DSD over coax, which is fine too in a sense, since downsampling to 192K makes not much of a difference to me sonically.

Well, coax 24/192 has enough bandwidth to do DSD direct (no PCM conversion) for DSD64. I have a lot of SACD rips and it works fine on several DACs, but I don't have a lot of samples to test at other DSD rates. I'm pretty sure DSD128 glitched over coax. But, many older coax setups only go to 24/96.
 
Oct 29, 2022 at 4:48 PM Post #366 of 583
I agree. Douk does DSD64 over coax, which is fine with me. The other DDS (with TCXO oscillators) doesn't do any DSD over coax, which is fine too in a sense, since downsampling to 192K makes not much of a difference to me sonically.
Just a note: DSD64 (44.1kHz based as from SACD source) is equivalent to the PCM 24/88.2kHz. Upsampling to 176.4kHz makes a sense, but 192kHz lose quality due to the sample rate conversion. I suggest 176.4k as it doesn't require SRC.

48kHz based DSD files are only available for testing purpose, then 196kHz conversion makes sense, but probability to get such sample is near zero.
 
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Oct 29, 2022 at 6:33 PM Post #367 of 583
Just a note: DSD64 (44.1kHz based as from SACD source) is equivalent to the PCM 24/88.2kHz. Upsampling to 176.4kHz makes a sense, but 192kHz lose quality due to the sample rate conversion. I suggest 176.4k as it doesn't require SRC.

48kHz based DSD files are only available for testing purpose, then 196kHz conversion makes sense, but probability to get such sample is near zero.

Right on dot. I wanted to mean, 192K is the highest sampling rate supported by coax through that DDC. However, the DAP actually sends out DSD64 as 24/88.2, as shown on the Neutron player display.
 
Nov 4, 2022 at 5:59 PM Post #369 of 583
Hello guys.

he said he was looking for a driver
https://forum.hifiguides.com/t/douk-u2-pro-with-upgraded-clocks-need-explanation/27327/106
Thesycon-Stereo-USB-Audio-Driver-v224
Will this work for u2pro?
I'm a beginner so I don't understand

thanks in advance
thanks for that, and nice to have control over latency settings in the TUSB audio control panel finally. The only negative is that it's an even older driver than the one uploaded by Douk. If anyone here knows how to edit a more recent xmos version to allow this, then that would be appreciated. But all good in the meantime..-)
 
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Nov 4, 2022 at 9:18 PM Post #370 of 583
If anyone here knows how to edit a more recent xmos version to allow this, then that would be appreciated
By editing ini files you lose MS certification. Driver is protected from editing inf files (there are encrypted catalog files), features are a part of a licencing scheme. These old drivers had different licencing restrictions, it had been gradually more limited with new versions. Don't expect from small Chineese vendors to license a full version of a driver.
 
Nov 4, 2022 at 10:23 PM Post #371 of 583
Or, just switch to Mac :)
 
Nov 5, 2022 at 10:50 AM Post #372 of 583
Understood and shame about the licensing situation, albeit understandable for a small company.

I will be keeping the Douk U2 pro (base version) though, which is sounding excellent regardless! Currently connected to my adi 2 dac FS with a cheap 30cm Van Damme plasma 75 ohm coax cable, from a Nuc i7, and its beating the RME's already good usb input, with added fine detail and crispness subjectively.

As regards upgrading the clocks, wouldn't it be wiser spending a bit extra still on something like a Matrix SPDIF?
 
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Nov 5, 2022 at 12:50 PM Post #373 of 583
As regards upgrading the clocks, wouldn't it be wiser spending a bit extra still on something like a Matrix SPDIF?
I agree, at the price of $150 or more, there are perhaps better options. If you have DIY skills, there is a module with isolated USB port for ~70€, it comes with fully licenced XMOS drivers and ultra-low jitter oscilators NDK brand as a standard. You need isolated USB when your source is NUC. It is called I2SOver USB from jlsound.com.

It has non diferential I2S (not for HDMI), but you are using coax output anyway.

Also look at the product of SunSky that I consider better designed to accomodate ultra-low jitter oscilators.
 
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Nov 5, 2022 at 1:18 PM Post #374 of 583
I agree, the other product that sajunky just mentioned sounds quite good, considering that its power comes from the USB. I have no problem powering it through my DAC or iPad USB-C. Compared to the Douk U2 pro, it delivers slightly better articulation/texture and microdynamics. This can be heard through both LCD3 and HD800, but HD800 benefits more from it in terms of instrument placement and texture. It really enhances the qualities that make HD800 special.

I am still waiting for the Douk with femto clock. It has cleared customs, so should be here next week.
 

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