[rb2013]

 

Any suggestions you may have on mods for the U12 are appreciated. 
 
As for the tube vs SS output on DACs - it comes down to the right tubes.  My favorite is the 6922 type.  After rolling these for 20 yrs - I have a pretty good idea of the best vintage available.  The finest like the early 60's Siemens CCa gray's or the 6N23P '75 Voskhods - are as solid, extended as any SS DAC I have heard.  What they add is a rich natural tone, better dynamics and a more holographic sound stage.
 
Cheers!

 

[prot]

 Sweet, let me know how it turns out. My DAC has AES input, so I can use either AES to AES from U12 to DAC, or coax to AES from U12 to DAC.

This is somewhat unexpected but the AES/XLR cable did not make any difference. Same volume level as Coax... somewhat quieter than direct USB to DAC. I'll just keep the AES cause it has very nice Neutrik connectors that sit very well into the sockets.
And btw, looks like all Gustard outputs are active simultaneously.

 

[Zoom25]

This is somewhat unexpected but the AES/XLR cable did not make any difference. Same volume level as Coax... somewhat quieter than direct USB to DAC. I'll just keep the AES cause it has very nice Neutrik connectors that sit very well into the sockets.
And btw, looks like all Gustard outputs are active simultaneously.

Thank you very much. This makes life much easier. I take it no difference in sound quality either?

 

[ginetto61]

   
Yes post pic of your transformer if you can. 

 
Good morning !
here the pic
 

 
I would not mess with the unit after all.  Maybe i would have preferred to see used a transformer of this type here
 

 
 
or this one here
 

 
 
 
if i am not wrong this types have primary and secondary windings separated.
Usually this results in a better rejection of mains noise ! this is fundamental with digital i suppose
 
But googling i see that toroidals are very fashionable these days ... actually the look really nice
But they also sound nice ?
They are instead the normal choice for power amps for instance.
Almost no one uses big and heavy EI transformer these days.
Personally i like more EI trasformer also for amps. It seems that they usually give a better bass ? 

 
Regarding tubes i guess you are right.
For line stages i have a predilection for the powerful tubes usually used as drivers for the output stages in many tube power amps.
For instance nobody cares of the 12bh7 ... for me this tube would be exceptional as line stage (even if no one is using it).
I am sure as you say that tube selection is the 1st step and very fundamental
i see almost everywhere ecc82 ... too weak tube for me.
The 12bh7 (or similar) correctly used could give exceptional sound ... clean, powerful, transparent ... everything.
One day maybe i will buy a kit from ebay adaptable to this wonderful tube.
 
Thanks again and kind regards,  gino 

 

[prot]

Thank you very much. This makes life much easier. I take it no difference in sound quality either?

None that I could hear. Connected both a viablue coax and the sommercable/neutrik aes and I could easily switch from the DAC. 100% same. But of course YMMV

 

[MINORISUKE]

I own U12 and am satisfied with its performance.
However, I found the following.  This model has RJ45 I2S output, which is easier to handle than LVDS of U12.
http://item.taobao.com/item.htm?spm=a1z10.1-c.w4004-9491014597.7.aI5USc&id=44130453324

 

[rb2013]

  I own U12 and am satisfied with its performance.
However, I found the following.  This model has RJ45 I2S output, which is easier to handle than LVDS of U12.
http://item.taobao.com/item.htm?spm=a1z10.1-c.w4004-9491014597.7.aI5USc&id=44130453324

Nice looking unit - I'm curious too

 

[hgpsemaj]

The USB interface (i.e. DI-2014.) of 'Audio gd' offers standard clock or upgraded TCXO.  And Mr Ho of 'Audio gd' just informed me, they can install OCXO to their DI-2014, but customer must supply and forward the OCXO to 'Audio gd'.
 
 
P.S. I've confirmed with Gustard, and they would not provide the above mentioned service for U12.

 

[rb2013]

   
Good morning !
here the pic
 

 
I would not mess with the unit after all.  Maybe i would have preferred to see used a transformer of this type here
 

 
 
or this one here
 

 
 
 
if i am not wrong this types have primary and secondary windings separated.
Usually this results in a better rejection of mains noise ! this is fundamental with digital i suppose
 
But googling i see that toroidals are very fashionable these days ... actually the look really nice
But they also sound nice ?
They are instead the normal choice for power amps for instance.
Almost no one uses big and heavy EI transformer these days.
Personally i like more EI trasformer also for amps. It seems that they usually give a better bass ? 

 
Regarding tubes i guess you are right.
For line stages i have a predilection for the powerful tubes usually used as drivers for the output stages in many tube power amps.
For instance nobody cares of the 12bh7 ... for me this tube would be exceptional as line stage (even if no one is using it).
I am sure as you say that tube selection is the 1st step and very fundamental
i see almost everywhere ecc82 ... too weak tube for me.
The 12bh7 (or similar) correctly used could give exceptional sound ... clean, powerful, transparent ... everything.
One day maybe i will buy a kit from ebay adaptable to this wonderful tube.
 
Thanks again and kind regards,  gino 

Thanks Gino!  You have the 9V transformer as well.  Same as my two.  I noticed the Melodious MX-U8 uses a better quality Talema transformer - at approx $175 USD I would love to try this one.
 

 
PS If they ever start selling on Ebay for US delivery I'd buy one for sure

 

[bavinck]

Forgive my ignorance. I am looking seriously at getting a Gustard x12 with USB. What does the U12 do?

 

[rb2013]

  Forgive my ignorance. I am looking seriously at getting a Gustard x12 with USB. What does the U12 do?

It's a USB PC interface - so it takes the digital stream from your PC and converts it to a digital stream your DAC can accept

 

[Arnotts]

  Forgive my ignorance. I am looking seriously at getting a Gustard x12 with USB. What does the U12 do?

I haven't done a proper, side-by-side comparison between the X12 with USB vs the U12 connected to the X12 via I2S, but I think I prefer the USB input right to the X12.
 
There was something I thought sounded slightly off with the sound from the U12 when paired with the X12 via I2S (I never tried other inputs/cables with it). Might have been the cheap HDMI cable that I used, but I've never used aftermarket cables before, so I don't know if I would be able to tell the difference or not.
 
The U12 provides a fantastic improvement to my Matrix M-Stage combo, though . Got it connected via TOSLINK.

 

[conquerator2]

I should receive my X12/U12#2 later this week. Hopefully I'll be able to comment further 

 

[ginetto61]

  Thanks Gino!  You have the 9V transformer as well.  Same as my two. 
I noticed the Melodious MX-U8 uses a better quality Talema transformer - at approx $175 USD I would love to try this one.
 

 
PS If they ever start selling on Ebay for US delivery I'd buy one for sure

 
Hi and you are welcome !
nice piece indeed. Maybe some reviews will show up soon. 
Given the good amount of 2nd hand dacs around the converters are a very good option in my mind.
Thanks again, gino 

 

[rb2013]

   
Hi and you are welcome !
nice piece indeed. Maybe some reviews will show up soon. 
Given the good amount of 2nd hand dacs around the converters are a very good option in my mind.
Thanks again, gino 

I like the fact there is lot's of room inside and a seperate board for the transformer.  Would be an easy mod to an RCore trannie.  Extra PS filtering - the beloved Murata transformers for the spdif.
 
I wonder if the seller will ship to the US and if it has switchable voltage to 110