It is board with DAC, of course analog power supply is separated. This spikes seen after LT3045 on 1.0V XMOS power rail, seems to be strange for such good regulator, anyway it sounds very good instead of PWM regulator. I'll try to power it from separate 1.5V transformer winding, may be LT behaves like this because of big voltage drop from 5V to 1V
As a result of experiments, I came to the conclusion that the most striking result is given by separation of power supply of VDD(core) and PLL_AVDD rails. Awesome improvement for sound. Now using two 1.0V regulators for these rails. It may be very usefull to users with different versions of XMOS, just look at schematics and datasheet (btw there is an simplified schematics in it, where these power supply pins are using the same regulator, but in text there mentioned that "The PLL_AVDD supply should be separated from the other noisier supplies on the board. The PLL requires a very clean power supply").
And here it is a difference even between regulators at PLL_AVDD.
Both powered by main linear supply with TPS7A4701, in both cases RC 4.7R+10uF are present at PLL_AVDD. In first case 1V for core and PLL_AVDD is made by 1117-3.3V > AP7365-10YG-13, in second by LT3045.
Both powered by main linear supply with TPS7A4701, in both cases RC 4.7R+10uF are present at PLL_AVDD. In first case 1V for core and PLL_AVDD is made by 1117-3.3V > AP7365-10YG-13, in second by LT3045.
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Did you try comparing two subsequent measurements with the same regulator? Did several measurements of the two regulators display similar difference? Thanks.
I wrote in another thread:
But as for me, more than 12 years, since I started to play with XMOS CPUs, I use 1117-3.3 and 1117-1.8 or LM3671 for digital power and AP7365 or TPS72010 for the core power (1.0v), with TPS3106K33 supervisor.
PLL is powered through 5.1 Ohm resistor and have 4.7uF X7R cap.
And had no problem yet.
P.S. Ans as I mentioned in another thread - all my USB interfaces have the external audio clock and galvanic isolation between USB and audio parts.
Alex.
But as for me, more than 12 years, since I started to play with XMOS CPUs, I use 1117-3.3 and 1117-1.8 or LM3671 for digital power and AP7365 or TPS72010 for the core power (1.0v), with TPS3106K33 supervisor.
PLL is powered through 5.1 Ohm resistor and have 4.7uF X7R cap.
And had no problem yet.
P.S. Ans as I mentioned in another thread - all my USB interfaces have the external audio clock and galvanic isolation between USB and audio parts.
Alex.
There is no problems, it works good in both cases. There is an audible difference.
No.
It was YOU, who said that there is an audible difference!
And others may say it doesn't.
A double blind test would show everything, but audiophiles always run from it like the devil from incense.
Alex.
@
Lucian (Lorien on this forum)
Anatolii_A:
Since I strongly feel this will spark a new debate, it would be advisable to open a new thread where you can post your findings, as this one is related to another build that can be seen in the first post of this discussion. There are other threads dedicated to discussing various improvements in XMOS implementations — my own approaches are listed in the first thread, including my take on how things can be implemented in hardware. As I said, any new ideas or approaches should be discussed separately to avoid confusion.Lucian (Lorien on this forum)