[abartels]

   
Thanks for the tips.  I made a custom power plan under Windows Control Panel to turn off power savings and never sleep or hibernate.  This issue happens with both the PC motherboard USB ports and the preferred Jcat PCIe USB adapter.   USB power is supplied by a clean +5V supply
 
The U12 unlocked this morning after about 30 minutes of use.  Went to the Off Ramp 5 and no problem.  I need to find the Luckit 2.26 driver.  Their 2.23 version does not load on my PC as it is not signed correctly for Windows 8.1 even though it states that it is supported.
 
It may be the U12 has a fault.  I restarted the PC, USB power supply, U12, and DAC but no audio output after a restart.  I have USB sniffer SW and Windows thinks that it is still shifting bits to the U12 but the U12 LCD display does not show correct sampling rate.    If I leave everything turned off for a while it will eventually come back.  Weird and frustrating. 

 
Hi DACLadder,
 
Did you remove the drivers, restart your pc, and installed the drivers again AFTER changing the XO's to Crystek ones??
I experienced some problems too with my U12 after changing the XO's to NDK's.
 
With my MX-U8 I had same procedure to follow,,,
 
Btw, you can disable driver-signing in Windows 8.1 so that you can install Luckit drivers.
 
http://www.howtogeek.com/167723/how-to-disable-driver-signature-verification-on-64-bit-windows-8.1-so-that-you-can-install-unsigned-drivers/
 
Hope this helps,
 
Regards,
 
Alex

 

[rb2013]

  The Crystek oscillators and rectifier cap change I installed about four days ago have run in enough to delivery great sound.  Notice less grain in the vocals.  The U12 is sounding so good it rivals the Off Ramp 5 via HDMI I2S.   The Off Ramp 5 gives up slightly more bass but the U12 is handling the upper mids (vocals) very well in comparison.  Soundstage almost as wide as the OR5.  
 
My biggest disappointment in the U12 is the USB interface from my WIndows 8.1 machine to the unit.  Occasionally the USB port becomes unlocked during playback and outputs only a low level tone.  The only way to recover is to power down the PC and restart the U12.   It happens using Foobar2000. JRiver MC, or just playing a game.  If I select tracks for playback and constantly pick different sampling rates then I have no issue.   If I let it play with one sampling rate for a long period then the USB port eventually unlocks and does not recover.  I never have this issue with the Off Ramp 5 or other DACs with USB ports.  I have written Shenzhen Audio (U12 distributor) but received no reply. This morning the U12 has played OK for 5 hrs. straight without error but have selected tracks after playing up to 3 or 4 straight through.   If anyone hears of a newer windows USB driver other than 2.26 please let me know.     

I never had any issue with my Gustards - but do with just one of my MX-U8's.  This is on a brand new music server I build around WIN 7 (waiting to see what WIN 10 is like).  It unlocks after a few hours.  But on mine I just need to close and reopen Foobar - then it plays fine.  I have tried everything in the book and 4 different version - nothing fixes it.  It's really just a slight annoyance - and my other MX-U8 also on an older WIN7 server plays fine - not issues at all.
 
I think it might be these XMOS chips - possibly some production variance.

 

[DACLadder]

Thanks again for your help.  I will try turning off driver verify and attempt to load Luckit 2.23 driver.   The issue also could be the U12 itself - wish I had another to try in its place.  I may buy another down the road or try this one on a different operating system..  I have a netbook running Windows 7 x64 that I will locate and try.   
 
I also plan to put an oscilloscope on the signals when its in this state but I have no schematic to go by so a shot in the dark.  The USB port sniffer software indicates the USB link is OK as I can see data packets sent.  Perhaps down stream of the Xmos.   There is an FPGA that accepts the Xmos signals and clock and drives the I/O ports.  Could be there as will.  The U12 hardware is fairly simple so not a lot to go wrong.

 

[DACLadder]

  Btw, you can disable driver-signing in Windows 8.1 so that you can install Luckit drivers.
 
http://www.howtogeek.com/167723/how-to-disable-driver-signature-verification-on-64-bit-windows-8.1-so-that-you-can-install-unsigned-drivers/

You learn something new everyday and thank you!   Loaded up the Luckit 2.23 driver first try after disabling the driver verifier in Win 8.1.  Great, I wanted to try different driver and plays perfectly so far.  Good info Alex!  Thanks again.... 

 

[ginetto61]

I never had any issue with my Gustards - but do with just one of my MX-U8's.
This is on a brand new music server I build around WIN 7 (waiting to see what WIN 10 is like) .

 
Hi and sorry to jump in.
May i ask which interface of the ones you have you like better ?
Have you checked the circuit ? which is the best design ?
I have both ... the Gustard U12 and the Melodious but i have listened the U12 not enough to form an opinion.
Thanks a lot,  gino

 

[rb2013]

   
Hi and sorry to jump in.
May i ask which interface of the ones you have you like better ?
Have you checked the circuit ? which is the best design ?
I have both ... the Gustard U12 and the Melodious but i have listened the U12 not enough to form an opinion.
Thanks a lot,  gino

Hi,  well so far I much prefer the MX-U8.  I have another U12 I just bought (my third - as I sold my other two original units after hearing the MX-U8), I want to try and mod it some more and see the results.
 
My MX-U8's have greater detail and a more incisive presentation - while remaining supremely musical and smooth.  The bass is very extended and well defined - the treble clear and transparent with absolutely no hint of glare or etch.  Tonally, they transmit a rich natural tone.  The sound staging is deep and holographic - more so then the U12.  Note I have two of the U8's one with Nichicon Fine Gold caps and the other with Nichicon HWs.  Otherwise they are stock.  I added dedicated power supply filtering on each (

Common Mode and Differential Mode), this did improve the clarity and transparency.  The U12's sound very good - but a bit veiled compared to the U8's in my systems.   Second note my three systems are very highly evolved - with high end sources, advanced designed music servers, and refined amps and speakers (and HP's in my third system HD800/Moon Black Dragon V2 cable).  So changes become very noticeable and distinct. 
 
With these units I have now tried 10 different DDC USB interfaces (see the beginning of the thread for the list) - without a doubt the U8's are amazing and hands down beat every other DDC I have owned.  They are not the best in terms of QC - but have very good components (Talema trans, Murata IT, etc...) and design (multiple layers of highly regulated and filtered PS).  I have not had the BADA or the Hydra X+ yet.

 

[ginetto61]

Hi,  well so far I much prefer the MX-U8.  I have another U12 I just bought (my third - as I sold my other two original units after hearing the MX-U8), I want to try and mod it some more and see the results.
My MX-U8's have greater detail and a more incisive presentation - while remaining supremely musical and smooth.  The bass is very extended and well defined - the treble clear and transparent with absolutely no hint of glare or etch.  Tonally, they transmit a rich natural tone.  The sound staging is deep and holographic - more so then the U12.  Note I have two of the U8's one with Nichicon Fine Gold caps and the other with Nichicon HWs.  Otherwise they are stock.  

 
Hi and thanks a lot for the very valuable advice.  I think i have found a very good piece indeed. I put the FGs already in my unit as well. 16V/2200uF. 
I like so much its flexibility. It gives me the opportunity to try every dac in the market and i have always a project to buy a good old one. 
The Melodious will be the corner stone of my future system. Actually it is already the cs of my present system. 

 I added dedicated power supply filtering on each (

Common Mode and Differential Mode), this did improve the clarity and transparency.  

Interesting, what is it in practical terms ? a filter ?

The U12's sound very good - but a bit veiled compared to the U8's in my systems.   Second note my three systems are very highly evolved - with high end sources, advanced designed music servers, and refined amps and speakers (and HP's in my third system HD800/Moon Black Dragon V2 cable).  So changes become very noticeable and distinct. 
With these units I have now tried 10 different DDC USB interfaces (see the beginning of the thread for the list) - without a doubt the U8's are amazing and hands down beat every other DDC I have owned.  They are not the best in terms of QC - but have very good components (Talema trans, Murata IT, etc...) and design (multiple layers of highly regulated and filtered PS).  I have not had the BADA or the Hydra X+ yet.

 
I am sure the U12 can only benefit from a better PS and PS can have a big impact on sound indeed. 
Of course a lot depends also on the quality of the mains voltage and the noise.  But usually there is always some noise coming from the electrical grid and the level of suppression of this noise in the power supply makes the difference.
Thanks a lot again,  gino 

 

[rb2013]

   
Interesting, what is it in practical terms ? a filter ?  

Just a dedicated power line filter to feed the U8 and the U12 - yes they do make a difference.  And for $85 a bargain.  I added second separate ones for the DAC - that was not much of an improvement over just running both the DAC and U8/U12 on one filter.  But I needed it any for a separate outlet for my tuner, turntable and phono pre-amp.  Those were helped as well in SQ.  What an easy add on.

 

[ginetto61]

  Just a dedicated power line filter to feed the U8 and the U12 - yes they do make a difference.  And for $85 a bargain.
I added second separate ones for the DAC - that was not much of an improvement over just running both the DAC and U8/U12 on one filter.
But I needed it any for a separate outlet for my tuner, turntable and phono pre-amp.  Those were helped as well in SQ.  What an easy add on.

 
Hi and thanks so much again.
Actually i have noticed poor mains noise filtering in both Gustard and Melodious.  I do not understand why they have skipped on this extremely important issue.

Just a different type of transformer, better diodes or some caps and chokes, of the type i have seen in other better units,  would have been very beneficial
and avoided the need of an additional external filter ?
Usually mains are quite dirty in the cities.
I have decided for a different approach.  A completely new PS feeding better filtered DC to the board bypassing transformer and rectifying diodes on the pcb
Actually i am thinking to desolder them ... i am sure this will be extremely beneficial ... completely sure.  Almost ...  

I have collected, thank you very much again, enough information telling me that the stock PS is a weak point.
Very very unfortunately i am not skilled enoug to mess with the parts on the pcb ... from the coming of smd i lost all my hopes about modification of circuits (PS aside of course that are not smd 

 )
Thanks a lot again.
Kindest regards,  gino

 

[DACLadder]

The Luckit 2.23 driver did not fix my issue of the U12 dropping out in the middle of playback and emitting a low-level tone.  Thank goodness the tone volume is low as it is unsettling to be listening intently and all of a sudden about a 2Khz tone. 
 
When the problem happens Windows 8.1 thinks the USB interface is normal as near as I can tell.  I can see packets being shifted with USB sniffer software so the problem is further downstream of the Xmos USB interface.  JRiver is running normally at the time.  The U12 just locks up and requires a power cycle to restart.  When the problem happens the LCD displays " - - - -".  It is like the U12 or parts of the U12 just reset and do not recover. 
 
The U12 electronics are fairly simple.  There is an Altera FPGA that takes in the Xmos data output plus the two clocks, reformats, and drives the I2S, serial outputs, and front panel LCD display.  I thoroughly checked the soldering on all components where I can and looks great. 
 
I haven't given up hope as I like a challenge but it will be difficult to reverse engineer the design and figure out the issue cause.  I have the U12 top cover removed and looking at signals trying to figure out how it works.  I also have Xmos datasheets and reference designs as a guide.   About the only thing I cannot check is the Xmos soldering as the package is a ball grid array.  And forget exchanging the Xmos as I do not have the equipment to resolder BGAs.   Hope you have better luck with your U12.

 

[MINORISUKE]

DSD channel swap from HDMI LVDS I2S/DSD (U12):
 
I posted in MX-U8 thread that my DSD channel mix (not swap) issue had been solved today.
At the same time, I found DSD channel swap (not mix) at least with my U12.
I used a conversion board of Tanly (HDMI LVDS I2S/DSD --> "normal" I2S/DSD).
PCM was no problem, but DSD channel swap happened.
Note that this has noting to do with a dffferent pin assignment of U12 vs. PS Audio, as Tanly's pin assignment is the same as that of U12.  If this is the reason, then PCM must be swapped, too, which is not the case.
 
I asked several owners of both U12 & DAC-X12 conneciting with an HDMI cable to check if DSD channel mix (not swap) happened.  All of them said the playback was normal (without mix, without swap).  I assume swapped channel from U12 is swapped again in DAC-X12 if connected via a HDMI cable.

 

[rb2013]

   
Hi and thanks so much again.
Actually i have noticed poor mains noise filtering in both Gustard and Melodious.  I do not understand why they have skipped on this extremely important issue.

Just a different type of transformer, better diodes or some caps and chokes, of the type i have seen in other better units,  would have been very beneficial
and avoided the need of an additional external filter ?
Usually mains are quite dirty in the cities.
I have decided for a different approach.  A completely new PS feeding better filtered DC to the board bypassing transformer and rectifying diodes on the pcb
Actually i am thinking to desolder them ... i am sure this will be extremely beneficial ... completely sure.  Almost ...  

I have collected, thank you very much again, enough information telling me that the stock PS is a weak point.
Very very unfortunately i am not skilled enoug to mess with the parts on the pcb ... from the coming of smd i lost all my hopes about modification of circuits (PS aside of course that are not smd 

 )
Thanks a lot again.
Kindest regards,  gino

I think trying to re-engineer the on board PS is maybe overkill - just add some well designed PS filtering and your set.  Remember the MX-U8 uses multiple stages of power rectification and filtering - including individual filtering and rec for each clock.
 
BTW I was reading in a HiFI magazine about this amazing DAC/USB that cost $5000 - it used three of the same Talema transformers as the MX-U8 - three of the exact same ones.  They can't be too bad.

 

[rb2013]

  The Luckit 2.23 driver did not fix my issue of the U12 dropping out in the middle of playback and emitting a low-level tone.  Thank goodness the tone volume is low as it is unsettling to be listening intently and all of a sudden about a 2Khz tone. 
 
When the problem happens Windows 8.1 thinks the USB interface is normal as near as I can tell.  I can see packets being shifted with USB sniffer software so the problem is further downstream of the Xmos USB interface.  JRiver is running normally at the time.  The U12 just locks up and requires a power cycle to restart.  When the problem happens the LCD displays " - - - -".  It is like the U12 or parts of the U12 just reset and do not recover. 
 
The U12 electronics are fairly simple.  There is an Altera FPGA that takes in the Xmos data output plus the two clocks, reformats, and drives the I2S, serial outputs, and front panel LCD display.  I thoroughly checked the soldering on all components where I can and looks great. 
 
I haven't given up hope as I like a challenge but it will be difficult to reverse engineer the design and figure out the issue cause.  I have the U12 top cover removed and looking at signals trying to figure out how it works.  I also have Xmos datasheets and reference designs as a guide.   About the only thing I cannot check is the Xmos soldering as the package is a ball grid array.  And forget exchanging the Xmos as I do not have the equipment to resolder BGAs.   Hope you have better luck with your U12.

Are you using the I2S outputs?  Does it happen on the SPDIF's?  One last try - the latest MB chipset designs have some tricky USB features.  I would go into the BIOS and turn on latency USB devices and turn off more advanced USB BIOS features

 

[abartels]

  The Luckit 2.23 driver did not fix my issue of the U12 dropping out in the middle of playback and emitting a low-level tone.  Thank goodness the tone volume is low as it is unsettling to be listening intently and all of a sudden about a 2Khz tone. 
 
When the problem happens Windows 8.1 thinks the USB interface is normal as near as I can tell.  I can see packets being shifted with USB sniffer software so the problem is further downstream of the Xmos USB interface.  JRiver is running normally at the time.  The U12 just locks up and requires a power cycle to restart.  When the problem happens the LCD displays " - - - -".  It is like the U12 or parts of the U12 just reset and do not recover. 
 
The U12 electronics are fairly simple.  There is an Altera FPGA that takes in the Xmos data output plus the two clocks, reformats, and drives the I2S, serial outputs, and front panel LCD display.  I thoroughly checked the soldering on all components where I can and looks great. 
 
I haven't given up hope as I like a challenge but it will be difficult to reverse engineer the design and figure out the issue cause.  I have the U12 top cover removed and looking at signals trying to figure out how it works.  I also have Xmos datasheets and reference designs as a guide.   About the only thing I cannot check is the Xmos soldering as the package is a ball grid array.  And forget exchanging the Xmos as I do not have the equipment to resolder BGAs.   Hope you have better luck with your U12.

 
 
Hello DACLadder,
 
You modified your U12 with Crysteks, and another LVDS output chip.
I would think there's something wrong with your mods.
 
The horizontal stripes on your U12 means the XMOS is not locked onto a frequency!!!!!!
 
 
I once had this problem when I wanted to demonstrate a friend how my U12 sounds with original Gustard XO's, and guess what happened?
No sound, and stripes on the display.
 
I figured it out, the housing of the XO's touched the pins which I soldered onto the pcb. Because the pins have a bigger diameter the housing
was connecting to the pins!!!
 
I dont know how your Crystek adapters look like on the bottom of the pcb, maybe they create some kind of short-circuit.
 
Check this please!
 
Good luck!
 
 
Regards,
Alex
 
 
EDIT:
 
Try putting back the U12 stock XO's and see if it solves your locking problem, just to narrow down troubleshooting. Be careful not to place them "to deep" on the sockets (pins)
to avoiding short-circuit. 

 

[abartels]

 
I think trying to re-engineer the on board PS is maybe overkill - just add some well designed PS filtering and your set.  Remember the MX-U8 uses multiple stages of power rectification and filtering - including individual filtering and rec for each clock.
 
BTW I was reading in a HiFI magazine about this amazing DAC/USB that cost $5000 - it used three of the same Talema transformers as the MX-U8 - three of the exact same ones.  They can't be too bad.

 
Hi rb2013,
 
Those Talema's aren't bad at all, but, the higher the Amperage the lower the DC-resistance, the better the dampingfactor (the resistance the powerrails see when looking back into supply).
Thats the reason why I chose for 2 Amp windings instead of 1.07 Amp windings of stock Talema ( my Noratel was 15VA 2x9V, so they had 15/18= 0.83 Amp windings only,,,,,,)
 
 
Regards,
 
Alex