[auvgeek]

   
Hello abartels,
 
Mr. Huang informed me X20 is designed with symmetric output stage, and he also claimed X20 focus on authentic and realistic sound. He will forward us the rear image of X20 tomorrow.
 
 
Regards,
 
 
hgpsemaj

Would you mind posting these details and images in the Gustard Amplifiers and DACs thread? I only recently started tuning into this thread, and I would have hated to miss important info on the X20 because I was assuming people would post it there...

 

[blasjw]

I contacted the seller about my defective MX-U8 and they're reluctant to replace it claiming that if SPDIF works then AES works too.  I respectfully disagree, especially after looking at the circuit board.  there any number of points of failure including the connector itself.  I see that the output goes through a transformer which also could be bad.
 

 

[ginetto61]

I contacted the seller about my defective MX-U8 and they're reluctant to replace it claiming that if SPDIF works then AES works too.  I respectfully disagree, especially after looking at the circuit board.
there any number of points of failure including the connector itself.  I see that the output goes through a transformer which also could be bad.

 
Hi and sorry again to hear of your bad luck with the unit.  I wonder if any form of guarantee is available.
It could be very well the case of a bad joint/part somewhere downstream the point where the AES signal is taken to form the SPDIF signal, assuming that the SPDIF works fine.
I would prefer AES over SPDIF because i read the opinion of a praised digital designer.  So if my dac had a AES input i would use that port.
They should check this for free (also because is not a big deal for a manufacturer ... even replace a board is not that big issue).
I received yesterday mine ... it works via AES.
Maybe it is too early to say ... but i am impressed very positively.  The sound is already very convincing. Detailed and relaxed and IMHO can only get better after break-in.
I would ask for service under guarantee.   They should provide that. Any manufacturer provides some form of guarantee.
However the unit is worth some trouble.  It is good.  Very.
Good luck.  Regards,  gino

 

[abartels]

   
Hello abartels,
 
Mr. Huang informed me X20 is designed with symmetric output stage, and he also claimed X20 focus on authentic and realistic sound. He will forward us the rear image of X20 tomorrow.
 
 
Regards,
 
 
hgpsemaj

 
Hi hgpsemaj,
 
Sounds great!
 
Cheers 

 
Alex

 

[hgpsemaj]

  I contacted the seller about my defective MX-U8 and they're reluctant to replace it claiming that if SPDIF works then AES works too.  I respectfully disagree, especially after looking at the circuit board.  there any number of points of failure including the connector itself.  I see that the output goes through a transformer which also could be bad.
 

 
 
Tell your seller stop taking a diabolical liberty.
 
All items manufacture by 'Melodious Audio' are coved by guarantee and warranty which are clearly stated in their official website as follow:
 

 

[ginetto61]

Hi i have a question on the Gustard U12 that i still have
 
Does anyone know if the U12  is " USB Class Compliant " ? 

 
i will test this asap but if someone already knows ... i am really curious.

Because i have an insane project in mind ... using an Android media player with the " Usb Audio Player Pro " app, that is said to work with USB Class compliant devices, as a source for the U12  

 
https://play.google.com/store/apps/details?id=com.extreamsd.usbaudioplayerpro&hl=en
 
I have come to the conclusion that the lighter the OS the better can be the sound
To check the weight of an OS one telling way is to look at its requirements for compatible HW
And Android OS runs also on very poor HW ....  but i have to try of course.
 
Thanks a lot,  gino

 

[SodaBoy]

Thanks hgpsemaj.
 
I think we need an X20 thread in the dedicated source component forum or the Gustard DAC thread should be moved there. I don't know why we have two Gustard threads in the headphone amp forum, one in computer audio, but nothing in the dedicated source component forum.

 

[Jamiee]

  I contacted the seller about my defective MX-U8 and they're reluctant to replace it claiming that if SPDIF works then AES works too.  I respectfully disagree, especially after looking at the circuit board.  there any number of points of failure including the connector itself.  I see that the output goes through a transformer which also could be bad.
 

 
That's rather unfortunate...  Keep working on the seller or maybe talk to the manufacture directly as they should swap out the unit for you (or at least change the main board for a fully working one).
 
I have verified that both COAX and AES out's work fine with my U8.
 
That said, I did something yesterday that I haven't done in a while....  I bypassed the U8 and plugged the USB cable directly into my April Music DP1 DAC.
After a driver re-install and setup - I can honestly say that I didn't realize what I was missing by playing around with these relatively inexpensive DDC's.  The U10, U12, MX-U8, are all very good in their own right, but I would be remiss to say that they do a better job than the DP1 on its own. 
Yes the DP1 is in a different price category - guess I was hoping it would be something of a David vs. Goliath showdown.
The amazing part is how close David get's to Goliath here, but the solid reality is that Goliath ultimately wins this battle of sonic prowess.
 
I also have an April Music Stello U3 DDC which I will put back in the mix over the next few days.  If my memory serves me correctly, the U3 is very similar sounding to the DP1 (after all the DP1 essentially has a U3 built into it), with maybe just a hair increase in overall resolution.

 

[ginetto61]

   
That's rather unfortunate...  Keep working on the seller or maybe talk to the manufacture directly as they should swap out the unit for you (or at least change the main board for a fully working one).
 
I have verified that both COAX and AES out's work fine with my U8.
 
That said, I did something yesterday that I haven't done in a while....  I bypassed the U8 and plugged the USB cable directly into my April Music DP1 DAC.
After a driver re-install and setup - I can honestly say that I didn't realize what I was missing by playing around with these relatively inexpensive DDC's.
The U10, U12, MX-U8, are all very good in their own right, but I would be remiss to say that they do a better job than the DP1 on its own. 
Yes the DP1 is in a different price category - guess I was hoping it would be something of a David vs. Goliath showdown.
The amazing part is how close David get's to Goliath here, but the solid reality is that Goliath ultimately wins this battle of sonic prowess.
I also have an April Music Stello U3 DDC which I will put back in the mix over the next few days.
If my memory serves me correctly, the U3 is very similar sounding to the DP1 (after all the DP1 essentially has a U3 built into it), with maybe just a hair increase in overall resolution.

 
Hi and thanks for the very interesting comparison. 
Which interface have you actually tested with the DP1 ?  U10, U12 or MX-U8 ?
in case you have tested more than one which one the best ?
Actually i think that if the usb input is very well designed and realized the fact to have it inside the dac is a benefit
Thanks a lot,  gino

 

[auvgeek]

  I contacted the seller about my defective MX-U8 and they're reluctant to replace it claiming that if SPDIF works then AES works too.  I respectfully disagree, especially after looking at the circuit board. 
 

If it's an online seller, please let us know who it is so I/we can avoid them.

 

[ginetto61]

Hi i bought my MX-U8 from this seller
 
http://www.ebay.it/usr/wsz0304
 
the unit works from the AES ,,, have not tried the other outs
Even brand new i like it very much.  I hope to have found a good bridge from the pc world to audio finally
But i have learned also something in the travel ... i made some mistakes of approach
For instance usb isolation with some units has no benefit.  With other instead remarkable improvements.
If spdif is what you need maybe some cheap units can perform nicely as well.  However they usually do not have AES out.
AES is a more pro standard. All pro dacs have one.
Pro dacs for me are a little underrated ... at least from a measurements point of view some are quite outstanding.
Bye,  gino

 

[auvgeek]

Thanks, gino! I used pollychen for my Gustard H10, so I'll probably go with him on the MX-U8, pending @blasjw response. But I wasn't trying to derail this thread into who you should buy from; I just thought it would be good for everyone to know if there's a seller reluctant to deal with an obvious warranty issue.

 

[ginetto61]

Originally Posted by auvgeek /img/forum/go_quote.gif  
 
...   But I wasn't trying to derail this thread ....

 
Hi me also i do not want to go OT.
Personally i think that the Melodious MX-U8 deserves a specific thread where to put experiences of use and so on.
I think it is a unit with a great quality/price ratio ...
Bye gino

 

[Skogkatt]

  I contacted the seller about my defective MX-U8 and they're reluctant to replace it claiming that if SPDIF works then AES works too.  I respectfully disagree, especially after looking at the circuit board.  there any number of points of failure including the connector itself.  I see that the output goes through a transformer which also could be bad.
 

The picture you posted shows that there are two 110 Ohm resistors missing: one resistor is in series to the primary of the
balanced out and the other one is close to the top left corner of the red rectangle. Both resistors are clearly soldered to the
PCB in other pics of the MX-U8 appearing in the WEB.
 
Whether deciding to return the unit is entirely up to you, it might be easier and faster soldering the resistors by your self: a couple of 220 Ohm
resistors in 0805 package soldered in parallel will give you a perfect 110 ohms like reported on the PCB (110 ohms is commonly used to
adapt the impedance of the balanced output which is 110 Ohm - a single 110 Ohm is of course better but it might more difficult to find).
 
Good luck.

 

[abartels]

   
Hi and thanks a lot for the very valuable reply
I do not understand the circuit ... one regulator and two diode bridges ?
Then i would try to connect the DC socket to the cap feeding this regulator ... but i see 4 blue caps ... which one is the possible docking point ?
Just to solder a two wires cable to its terminal and it should be done.  Am i wrong ?
And in this way there will be two stages of regulation in series, for an even lower resulting noise.  Very low.
I am quite sure i will do the mod after measuring the voltage on the caps.
Thanks again,   gino

 
I myself would (and will) go for external feeding XO's with ultra low noise psu.
You can order the 0.8uV ultra low noise from DIYINHK, as earlier posted. It is a double version and needs 2 seperate 6~ to 8~ Volt transformer ( transformer 6Vx2 15VA).
 
If you doing so, also replace the stock XO's (which aren't bad at all). Just put them on a socket and configure that socket to receive its GND and Power from 0.8uV psu.
 
Please be aware to jumper the 0.8uV psu to 3.3V output before connecting everything.
 
I have the components at hand to install 0.8uV psu, only need one 2x6V~ transformer which will fit in MX-U8.
 
Btw, if placing 0.8uV noise psu, be aware that the stock Panasonic caps won't fit in enclosure MX-U8. You need lower profile caps.
The 0.8 uV ultra low noise psu (  http://www.diyinhk.com/shop/audio-kits/73-08uv-ultralow-noise-dac-power-supply-regulator-33v5v-1ax2.html  ) has 2x Panasonic FC 5600uF-25V with a hight of 40mm.
 
I advise replacing them with Nichicon HW series 4700uF-25V ( UHW1E470MHD ) with a hight of 31,5mm
You could try 5600uF-25V ( UHW1E560MHD ) with a hight of 35,5mm, but I'm not sure if it will fit.
 
There's not much room to place this psu, best is to remove faceplate and mount psu on its top (top of the caps) at bottom plate, and fix it with some "construction kit".
Be sure you can connect the wires after mounting the pcb, and be sure you don't short circuit anything,,,,,
 
 
I will post some pictures when starting this mod.
 
Cheers 

 
Alex