Melodious MX-U8 USB Interface 8 Core XMOS chip

[hgpsemaj]

Hello Alex,
 
Yes, I also consider separated transformer pcb is more desirable. And, I doubt Melodious would offer Noratel transformer as an option in this sort of one piece pcb any more.
 
 
 
Regards,
 
 
Riemann

 

[rb2013]

Hi Guys I have an extra MX-U8 for sale with the Nichicon HW caps - other wise stock.
 
$100 - PM if interested.  SOLD

 

[vincponc2610]

Any chance for a Melodious with LT3042, NDK or Crystek XOs, PS RFI/EMI filtering ?
an abartels-like one

 

[ginetto61]

  Any chance for a Melodious with LT3042, NDK or Crystek XOs, PS RFI/EMI filtering ?
an abartels-like one

 
Hi ! sorry but i missed the discussion LT3042 versus LT1063 ... in which way the 1st is better than the 2nd ?
i saw that maybe the LT3042 power supply noise suppression is better at high freq ... is this the point ?
By the way from this picture
http://www.head-fi.org/t/767935/lightbox/post/11890329/id/1444786
i see that the board has been changed.  Does anyone know if it is better than the original version ?
Thanks a lot,  gino

 

[vincponc2610]

Melodious has a two stage power supply with 1*LT1963 + 8* ADP150, each going to a different piece ( 1 for each of the 3 TCXOs, 4 rails for XMOS and 1 for optical output it seems)
 
LT1963 has 40uV noise, ADP150 has 9uV noise, and LT3042 has 0.8uV noise and has way better power supply noise rejection at any frequency, about 20-30db better than ADP150.
But LT3042 is 10 times more expensive than ADP150. ADP150 is about 0.5$, LT3042 is about 5$.

 

[ginetto61]

Melodious has a two stage power supply with 1*LT1963 + 8* ADP150, each going to a different piece ( 1 for each of the 3 TCXOs, 4 rails for XMOS and 1 for optical output it seems)
LT1963 has 40uV noise, ADP150 has 9uV noise, and LT3042 has 0.8uV noise and has way better power supply noise rejection at any frequency, about 20-30db better than ADP150.

Hi and thanks a lot for the kind and very helpful advice.
A much better regulator .. i understand.
Quote:

But LT3042 is 10 times more expensive than ADP150. ADP150 is about 0.5$, LT3042 is about 5$.

and this is what drives me crazy ... who would not be willing to pay 5 USD more for a much better and key component ? who ????
From what i understand the LT3042 could be used instead of the LT1963 and provide much more noise free voltage to the circuits downstream.
To hear this is to want it immediately.
I do not think it is a direct replacement for the LT1963, unfortunately.
Is this one the only kit available ??? i need a kit to have any chance ...
 
http://www.diyinhk.com/shop/accessories0/73-08uv-ultralow-noise-dac-power-supply-regulator-33v5v-1ax2.html
 
http://www.diyinhk.com/shop/282-thickbox_default/08uv-ultralow-noise-dac-power-supply-regulator-33v5v-1ax2.jpg
 
Thanks a lot again for the very valuable information.
Kind regards, gino

 

[abartels]

  Hi and thanks a lot for the kind and very helpful advice.
A much better regulator .. i understand.
Quote:
and this is what drives me crazy ... who would not be willing to pay 5 USD more for a much better and key component ? who ????
From what i understand the LT3042 could be used instead of the LT1963 and provide much more noise free voltage to the circuits downstream.
To hear this is to want it immediately.
I do not think it is a direct replacement for the LT1963, unfortunately.
Is this one the only kit available ??? i need a kit to have any chance ...
 
http://www.diyinhk.com/shop/accessories0/73-08uv-ultralow-noise-dac-power-supply-regulator-33v5v-1ax2.html
 
http://www.diyinhk.com/shop/282-thickbox_default/08uv-ultralow-noise-dac-power-supply-regulator-33v5v-1ax2.jpg
 
Thanks a lot again for the very valuable information.
Kind regards, gino

it's this one, new version:
 
http://www.diyinhk.com/shop/audio-kits/89-08uv-ultralow-noise-dac-power-supply-regulator-3357v-15ax2.html

 

[ginetto61]

it's this one, new version:
http://www.diyinhk.com/shop/audio-kits/89-08uv-ultralow-noise-dac-power-supply-regulator-3357v-15ax2.html

Hi Alex thanks a lot.
very impressive specs indeed

... max 200 mA aside

 
Thanks,  gino

 

[vincponc2610]

  Hi and thanks a lot for the kind and very helpful advice.
A much better regulator .. i understand.
Quote:
and this is what drives me crazy ... who would not be willing to pay 5 USD more for a much better and key component ? who ????
From what i understand the LT3042 could be used instead of the LT1963 and provide much more noise free voltage to the circuits downstream.
To hear this is to want it immediately.
I do not think it is a direct replacement for the LT1963, unfortunately.

 
It is not directly replacable.
LT3042 would be more instead of ADP150, not so instead of LT1963.
LT1963 provide current for everything. LT3042 might not be enough for everything, but enough for each components.
BTW, LT3042 was released beginning of 2015, so before Melodious made its design.
At this time ADP150 was a decent regulator.
 
On price, 5usd * 8 = 40usd, and the caps to put around might not be the same as ADP150.

 

[ginetto61]

Originally Posted by vincponc2610 /img/forum/go_quote.gif
It is not directly replacable.
LT3042 would be more instead of ADP150, not so instead of LT1963.
LT1963 provide current for everything. LT3042 might not be enough for everything, but enough for each components.
BTW, LT3042 was released beginning of 2015, so before Melodious made its design.
At this time ADP150 was a decent regulator.
On price, 5usd * 8 = 40usd, and the caps to put around might not be the same as ADP150.

 
Hi and thanks a lot again for helping me to understand better. Very kind of you.
Yes ... i have seen 200 mA max from the LT3042.
The more i think about it the more it seems to me that the key component is the LT1963 and that it has limits.
Providing better 5VDC to the board the ADP150 chips will be fed with lower noise voltage and so not be asked to do the cleaning-up work ?

and then maybe they could be left in place.  They will not have noise to suppress i mean.
The LT1963 seems not the best solution indeed (especially for its high freq noise poor performance).
I wonder which regulators the Hydra Z, the actual usb to spdif benchmark from what i understand,  uses for instance.
Thanks again,  gino

 

[vincponc2610]

   
Hi and thanks a lot again for helping me to understand better. Very kind of you.
Yes ... i have seen 200 mA max from the LT3042.
The more i think about it the more it seems to me that the key component is the LT1963 and that it has limits.
Providing better 5VDC to the board the ADP150 chips will be fed with lower noise voltage and so not be asked to do the cleaning-up work ?

and then maybe they could be left in place.  They will not have noise to suppress i mean.
The LT1963 seems not the best solution indeed (especially for its high freq noise poor performance).
I wonder which regulators the Hydra Z, the actual usb to spdif benchmark from what i understand,  uses for instance.
Thanks again,  gino

 
Output noise should be: rated output noise + PSSR * input noise.
 
So, yes having the first stage having low noise is important.
BTW, looking at this page https://hifiduino.wordpress.com/2011/03/29/new-breed-of-ultra-low-noise-regulators/ TPS7A4700 has 1000mA output, 4uv output noise, and a PSSR of 60db <100KHz, instead of 40db for LT1963
so that would make a robust first stage regulation for LT3042.
 
A 10 times better first stage for a 10 times better second stage.

 

[ccschua]

I can confirm that TPS7A can source the power as I had used it to power up the OCXO. 
 
if I am using TPS 7A (Tekdevice from ebay), can I remove existing 220uF cap and replace it with the output of TPS 7A? 

 

[rb2013]

   
Hi and thanks a lot again for helping me to understand better. Very kind of you.
Yes ... i have seen 200 mA max from the LT3042.
The more i think about it the more it seems to me that the key component is the LT1963 and that it has limits.
Providing better 5VDC to the board the ADP150 chips will be fed with lower noise voltage and so not be asked to do the cleaning-up work ?

and then maybe they could be left in place.  They will not have noise to suppress i mean.
The LT1963 seems not the best solution indeed (especially for its high freq noise poor performance).
I wonder which regulators the Hydra Z, the actual usb to spdif benchmark from what i understand,  uses for instance.
Thanks again,  gino

Hi Gino,

Remember the Hydra is designed for an external power supply - so that is where most of the regulation has to occur.  Unlike the U12, MX-U8, Breeze Audio - where the AC power supply is located in the same device.  One of the advantages of course with the Hydra Z approach is the ability to use a 5VDC Li Ion battery for power.
 

   
Output noise should be: rated output noise + PSSR * input noise.
 
So, yes having the first stage having low noise is important.
BTW, looking at this page https://hifiduino.wordpress.com/2011/03/29/new-breed-of-ultra-low-noise-regulators/ TPS7A4700 has 1000mA output, 4uv output noise, and a PSSR of 60db <100KHz, instead of 40db for LT1963
so that would make a robust first stage regulation for LT3042.
 
A 10 times better first stage for a 10 times better second stage.

Nice link!   I don't see the renowned LT3042 on the list though? 
 
BlogGear makes an excellent point:

 Just like phase noise in clocks, it is difficult to compare noise values among linear regulators because there is no common ground in specifying noise figures. Some companies report noise density, others RMS V noise, and yet others % of Vout. The frequency range for the reported noise figures also varies from company to company.

He did not compare ripple rejection by frequency - which is important,  As one of the key functions of the linear regulator is to filter out power supply ripples and noise.  Best to measured by freq and analyzed as a graph versus just a static figure.  From my experience looking these most of the LDO's have a big drop off in ripple rejection as freq climbs.
 
For the excellent ADM7151 this can be found on page 9 of the PDF the data sheet.
http://www.analog.com/media/en/technical-documentation/data-sheets/ADM7151.pdf
 
Same for the LT1963: top of page 11
http://cds.linear.com/docs/en/datasheet/1963aff.pdf
 
Note excellent ripple rejection of the TI LM 2941 used in the Breeze Audio (additionally uses two for a double regulation stage).  Middle of page 8
http://www.ti.com/lit/ds/symlink/lm2941.pdf

 

[ginetto61]

Hi Gino,
Remember the Hydra is designed for an external power supply - so that is where most of the regulation has to occur. 
Unlike the U12, MX-U8, Breeze Audio - where the AC power supply is located in the same device. 
One of the advantages of course with the Hydra Z approach is the ability to use a 5VDC Li Ion battery for power. 

 
Hi and i think i have some issues with the english ... it is only my 5th language ... 

Question ... what stops us to mod the Melodious to get a Hydra like unit ... what ?
Clearly the power supply section up to the lt1963 included is its weak point ... i do not have a scope but i am pretty sure that at its output there is a lot of noise.
Placing a dc socket on the back, desoldering the 220uf cap after the lt1963 and soldering a wire between the dc socket and the board and voilå ... you have a Hydra-like Melodious.
Then you can use the very best 5VDC power supply you can find/build ... with most the regulation occurring in this external power supply.
At that point even the stock ADP150s could be kept ... they will not have to suppress anything. The supplied voltage will be perfectly clean.
I like the Hydra approach so much better instead of a power supply inside the unit... very very better. No EMI emission ...no vibrations ... nothing. 
Thanks again, gino 

 

[vincponc2610]

  Nice link!   I don't see the renowned LT3042 on the list though? 

 
Because the post is from 2011, LT3042 is from 2015