I appreciate the moderators for keeping this thread focused on the topic. The discussion has been beneficial.
Even tho I started this topic, I’ve refrained from posting many comments here because I haven’t felt the need to do so. Before the thread is closed, I thank the Roon team for the wonderful Roon software I and my family use everyday.
Music Is Good
And even better when enjoyed through a microRendu! 
Must play the Mission Impossible theme later.
SJB
My sincere thanks to the moderators also.
Amir signing off. 
Thank you all for your respective contributions. Some very interesting technical diversions in this thread to re-read and digest over time.
Folks who have found us by this thread are welcome to stay and contribute to other discussions. As you have seen, we’re not a laissez-faire forum and prefer a more structured polite discourse, but we are hopefully tolerant of a broad range of opinion.
Having just come across this thread and having read the other one at a site that claims to cover audio science, I am surprised by the reasoning and logic that seems involved.
Hence I would like to raise an open question to Amir and anyone else, dispassionately and without appealing to emotions or creating FUD etc. about what this device or that thing does.
Amir claims “microRendu is highly sensitive to power supply noise.”. And he posts measurements that he claims prove this when using a specific power supply from a specific manufacturer.
Meanwhile the power supply manufacturer posted measurements that show their power supply to have essentially no relevant noise in the output and Amir used the “noisy” power supply in a different setup, which showed no noise. Someone else also measured the power supply in question previously and shows practically no 50Hz mains noise (as the measurements were done in in England).
So we have:
An audio test system with a source that shows a lot of noise based on mains frequency. I am eyeballing perhaps 40uV of 60Hz noise in Amir’s measurements if the scaling is as I expect.
The source is small computer plus a DAC both, powered via a DC power supply with additional local regulation in the computer as 9V powers neither USB nor Computer chips directly.
This local regulation should reduce any noise further and there is no 50/60Hz related switching frequency or AC power supply voltage anywhere within this source or attached to this source, other than the DC power supply.
Given these three simple facts I cannot reconcile Amir’s original statement that: “microRendu is highly sensitive to power supply noise.” with any currently known law of physics.
If the mico rendu did zero to reduce any incoming power supply noise, it could never produce more mains related noise on the output than it receives on the input.
Yet it would seem that Amir claims that somehow the micro rendu takes a few microvolt 100 (or 120Hz) noise and somehow creates more than ten times this level noise AND halves the frequency of this noise.
It would be nice if Amir would provide his scientific reasoning on the mechanisms in the micro rendu that create this noise out of apparently thin air.
If anyone else has suggestions as to how and why Amir’s measurements would show much more mains related noise from the DAC output in the tested source than is actually input into the system by the power supply, I’d also appreciate the comments.
M.I.
Hi M.I. - don’t want to stoke up controversy but your question deserves an answer.
What iFi measurement shows is the correct way to measure the noise from the iPower SMPS power supply.
Now if this is done the wrong way i.e.with ground loop issues, then the noise measurement raises by a significant amount as they also show in their measurements. The reason for this being that the leakage noise which is part of every PS is not shunted to ground in the normal way but is instead being shunted through the Audio Precision’s signal ground & appearing in the measurements
This is also what Amir’s measurements shows - a ground loop issue.
I hope this answers your question?
@ mods
Thank you for maintaining the civility of this thread & not allowing it to descend into personal abuse. As a result of your efforts, it is much easier for readers to hear both sides of an argument & judge the value of each for themselves
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