Objective proof the UpTone Regen ISO can improve a DAC's output(*)

[pkane2001]

31 minutes ago, plissken said:

As some may or may not be aware Amir at AudioScienceReview.com has been benching DACs for some Jitter/Distortion base lining.

 

The worst measuring DAC he has is a Schitt Modi 2 that he applied the Regen ISO against (other DAC's remained unaffected).

 

 

Looks like it cleans up the dirty 5v supply pretty well.

[pkane2001]

7 minutes ago, internethandle said:

Well you could reverse that question and ask why one SHOULD trust Amir. Isn't one of the functions of objectivism espousing the idea that one prove that something is true before asking that it be disproven? I could be totally mistaken, but I haven't seen any credentials from him other than retired tech executive with apparently a lot of cash to burn and (purportedly) an Audio Precision Analyzer. Other than that there's a paucity of information about who he is/might represent, what exact equipment and conditions he tests with/in, etc.

 

The power of objectivism is not in placing trust in someone based on credentials. The power is that the measurements can be repeated by any number of other parties (with or without credentials), in order to prove or disprove the original finding. 

 

If you don't trust Amir, wait for others to publish similar measurements. Or do your own. Which is why, I think, the manufacturer should publish their own measurements if they disagree with Amir's findings or his methods. Claiming that he's biased is not the way to disprove measurements, as all that does is accuse him of faking results without evidence.

[pkane2001]

3 hours ago, Superdad said:

 

But it is completely obvious that what he is measuring are the byproducts of the leakage current loop being formed by the interaction of leakage currents between the supplied Mean Well SMPS and the SMPS of his Audio Precision analyzer!

 

Alex, so why is it that ISO Regen with its ground isolation and noise blocking capabilities isn't stopping these ground loops? I thought that's what it was designed to do?

[pkane2001]

54 minutes ago, Superdad said:

 

Because it is not a ground loop he is forming (though if he puts the ISO REGEN switch in the defeat position, his setup--using single-end connection to the AP and having the same computer connected to both the DAC and the analyzer--would surely form one of those too!).  No, he is forming an AC leakage current loop.

 

That is very different.  It is a significant, widely overlooked issue in audio (and even with measurement equipment), and it very many exists, as exemplified by Amir's graph--which he completely misinterpreted as being the ISO REGEN putting mains noise on the 5VBUS line into the DAC.

 

John has written extensively about leakage/loops.  He has explained:

• what they are (AC traveling over every sort of connection including DC connections);
• where they come from (virtually every power supply; linears have leakage though not as much as switchers, and batteries have none);
• why they form (must be two PSUs--it is the interaction between two or more);
• and how best to mitigate them (reduce impedance between gear by plugging all system mains power cords into a heavy power stirip with zero filtering elements--use a low interwinding-capacitance isolation transformer for protection of gear)

By the way, one of the hallmarks of our own UltraCap LPS-1, its raison d'etre, is that by being "battery-like" (without the performance shortcomings of batteries), it blocks the path of leakage currents.  Or I should more correctly say that it keeps the device being powered from contributing any PS leakage the system's leakage loops.  EVERY audio system has leakage loops, but the combination of the ISO REGEN and the LPS-1 is what creates a complete "moat" between the computer (with its very high and typically quite nasty and "bursty" leakage) and the DAC.

 

Remember, galvanic isolation (just one of the functions of the ISO REGEN) is the blockage of DC not AC.

 

Thanks, Alex. So ISO Regen does not help with AC leakage currents from its own supply, is that fair? Does that mean that LPS-1 is needed with ISO Regen to help eliminate these?

 

By the way, it's easy enough to test which supply the noise comes from. I have an old power regenerator device from PS Audio that allows me to set the power frequency from 50Hz to over 100. Having the DUT or the measuring device plugged into a different frequency mains will quickly reveal which device is leaking AC (a test I've done with my DACs).

[pkane2001]

21 minutes ago, scan80269 said:

Alex & John have stated that an AC leakage loop requires at least two power supplies to form.

 

Hi Scan,

 

I understand that LPS-1 might help to break up these AC leakage currents, this goes back to the recommendations you made to power SU-1 DDC with one of these  I guess it is then important to buy ISO Regen and LPS-1 as a package, otherwise you are leaving some noise 'on the table', so to speak, or maybe even adding some additional noise due to the Meanwell SMPS that wasn't there before inserting ISOR.

 

If two power supplies are required for an AC leakage loop to form, does that mean that the loop is formed by the common wiring (in the wall) shared by both power supplies? Can you please describe or draw a high-level pathway of how this leakage current occurs between devices and power supplies, it seems a bit hazy in my mind?

[pkane2001]

4 hours ago, scan80269 said:

Per my understanding, yes.  The two AC power cords and the common wiring (in the wall) form part of a specific AC leakage loop.  The loop involves both AC and DC sections of each power supply.  Both SMPS (switching) and LPS (linear) supplies will contribute to AC leakage, though the SMPS are typically the worse offenders.

 

Let's take my previous example and elaborate a bit further.  We'll start at an AC wall socket.

 

AC wall socket #1 <> AC power cord <> Meanwell SMPS <> DC power cable <> ISO REGEN ("downstream" side) <> USB cable <> DAC/DDC <> internal DC cabling <> DAC/DDC power supply <> AC power cord <> AC wall socket #2

 

The common wiring (in the wall) completes the above AC leakage loop.

 

ISO REGEN serves to block noise and clean up USB signal coming from a dirty upstream USB port, such as from a PC.  The IR by its design does not offer blockage against AC leakage loops such as the above.  Since power supplies are always involved in the forming of an AC leakage loop, the task to break the loop largely falls to one (or more) of the involved power supplies.  UpTone LPS-1 is a linear power supply that has highly effective blockage against AC leakage loops.  Think of it as a firewall against AC leakage currents.  A DC battery also has this capability by virtue of not having a connection to AC whatsoever.

 

When you power an ISO REGEN with LPS-1 supply or battery, you achieve "total" isolation from the dirty upstream USB source, as well as freedom from an AC leakage loop.

 

Hope this helps!

 

 

Thanks, Scan! That makes sense.

 

What is still not apparent to me is what other effects ISO-R has on noise and leakage currents beyond what might be solved by LPS-1 (or a battery). While it might be that LPS-1 will fix the AC leakage currents that show up in Amir's measurements with SMPS, and the 5v line is also cleaned up, I don't see any other effects of ISO-R on noise or jitter.  Also, the AC leakage currents don't seem to be a problem for a few of the other DACs that he had on the bench, so there may not be a need in LPS-1 for these?

 

[pkane2001]

29 minutes ago, plissken said:

Nothing I've seen or heard so far would convince me it's a problem for most DAC's. The power supply in my Emotiva DC-1 is pretty robust and most likely takes care of the issue. 

 

I'll add my Gustard X20Pro to this list: I see no AC-related frequencies in the DAC output. I do see a slight bump of a few dB over the noise floor at 120Hz, but this is related to my ADC (which is using an SMPS). The reason I know this is that only my ADC is running at 60Hz, the rest of the equipment is powered by a 70Hz AC power.

[pkane2001]

5 minutes ago, Superdad said:

 

Yes, plissken is "Jinjuku" at ASR (he is more polite here than there).  Dennis (esldude here) is Blumlein88 there.

 

It's nice to match monikers to their owners on other forums  Provides more insight into how people think and interact with others. 

[pkane2001]

50 minutes ago, scan80269 said:

My concerns with Amir's measurements are not so much that they are invalid or improperly done, but rather in how he interprets the measurements and reaches over-generalized conclusions with them.

 

Scan, I respect your knowledge and expertise. I don't necessarily agree with Amir's conclusions, either, but by doing the initial measurements and sharing them with others he has began to advance our knowledge and understanding, well beyond what was previously available -- mostly marketing generalizations and noise. Other measurements and tests will come with time, but at least for me, his measurements and the discussion they engendered have already helped my understanding quite a bit.

[pkane2001]

35 minutes ago, scan80269 said:

Regarding jitter, Amir (and/or his followers) have adopted an assumption regarding the total correlation between incoming USB signal jitter and DAC analog output jitter.  Has it occurred to you that some DACs may be capable of complete de-correlation between the two two jitters, i.e. high incoming USB jitter doesn't necessarily translate to high analog output jitter?  Better DAC designs should be able to take a boat load of bad incoming USB jitter and signal integrity (waveform, etc.) and still output excellent analog with no hints of the USB crap coming through.  With such DACs I would not expect the ISO-Regen to yield much tangible SQ benefit, if at all.

 

 

 

Scan, I'm not clear as to what point you're making here. Are you saying that uncorrelated jitter might not manifest itself at the DAC outputs and yet, can affect SQ? Or that some DACs are just not subject to the incoming USB crap and therefore the output will not exhibit jitter, regardless? If former, I'd like to understand how that's possible that an audible effect is not measurable in the analog domain.

[pkane2001]

1 hour ago, Quadman said:

 

Why not tell Amir to repeat the test but this time put the lab PSU on the AP analyzer and put the SMPS supply back on the IR, if that cleans up the result like the lab supply did when put on the IR then you have to give credibility to Alex's explanation, and amir would have to admit such error in his measurements and reporting of.

 

I could be wrong, but I don't think AP analyzers allow for an external DC power source. Otherwise, this would be a good test.

 

[pkane2001]

1 hour ago, scan80269 said:

And I suggested yesterday that Amir replace the Mean Well SMPS with a battery to power the ISO REGEN and re-measure.  A purely scientific control experiment with only one component changed.

 

UpTone's LPS-1 power supply should also do the trick, but given Amir's obvious anti-UpTone stance, I thought a battery would at least be "neutral territory".  

 

Amir measured Behringer DAC while powering ISOR from his lab power supply. All the noise related to Meanwell PS went away, so I'm not sure why measuring with a battery or LPS-1 would prove  anything.

[pkane2001]

7 minutes ago, Speed Racer said:

Amir seems limited to just measuring which only part of the story. I would argue the least important part too. 

 

And what's the most important part? Sighted, unreliable, impossible to duplicate subjective listening?

[pkane2001]

6 hours ago, bibo01 said:

- Testing with static signal is pretty pointless, most of all to draw conclusions on SQ. One has to use dynamic signal at DAC output and confirm results with actual music too.

 

So, would you say that a measurement that shows that there is an actual AC noise linkage between the power supply of a DUT and a DAC is pointless, but listening to actual music using  an $8K power cord (as an example) is not?

 

[pkane2001]

1 hour ago, lmitche said:

The design of a testbed is subjective, as is the interpretation of test results.

 

It's an objective result that ISO-R with Meanwell PS caused more AC noise in an otherwise very clean DAC output. It's an objective result that replacing Meanwell by a lab LPS removed this noise. Don't know what your interpretation is, but mine is that the inclusion of ISO-R with Meanwell PS can cause additional noise to be injected into the DAC.

 

Speculation about AC leakage loops formed by AP Analyzer is the subjective part in this discussion, provided with no objective evidence to back it up.

[pkane2001]

2 minutes ago, bibo01 said:

Nice logic.

Makes sense to me. You said static measurements are pointless, but listening to music is not. I gave you two counter examples to what you said.

[pkane2001]

3 minutes ago, bibo01 said:

I said measuring dynamic signal and confirm results with music. It's possible to measure music too.

Got you.

[pkane2001]

4 minutes ago, lmitche said:

I can't think of a single person, of the 10 or so people I know that own a ISO REGEN, that uses anything but an LPS-1 for power,  Amir's assumption is that everyone chooses to purchase the ISO REGEN with a Meanwell is incorrect.  The Meanwell is an option at time of purchase. Perhaps Alex can tell us the the ratio of those that do so.

 

Again the design of the test is incorrect, or incomplete.

 

It would be nice to know if LPS-1 is needed for proper ISO-R operation. A $325 ISO-R price tag is significantly different than the $655 bundle with LPS-1.

 

[pkane2001]

Just now, lmitche said:

Yes, of course, but if you need to think of the $655 bundle in the context of the cost of the entire system.  For a $1000 system it's probably overkill, for a $40k system, it's more than reasonable. Everyone has to determine where that line is for themselves.

 

Yes, which is exactly why Amir's measurements are useful, at least to me. $655 is almost the price of my DAC, and I can't see spending that much money on a USB clean-up device. $325 was much more within the realm of possible  I did consider buying ISO-R, but was holding out to see some measurements. Seems to me that was the right move.

 

[pkane2001]

39 minutes ago, scan80269 said:

Audiophiles place their faith on the most sophisticated audio instruments available: their own ears.

 

How many mistakes do you think audiophiles have made when evaluating differences between components? How many placebos were picked over the years? How many of us swore we heard the differences caused by quantum dots or ink on the edges of a CD? How many preferred isolation platforms for their SS power amps because 'they sound better'? Or liquid interconnects, or cryogenically annealed speaker cables? Or $8K power cables? Or grounding boxes? I could go on, and on. I've been at this since the early nineties, and I've seen (and tried) all kinds of stuff.

 

One thing that has become abundantly clear to me is that while the audiophile ears are indeed, a very sophisticated instrument, audiophile brains are often not so much. And, unfortunately, the two are inseparable

 

[pkane2001]

55 minutes ago, Quadman said:

@pkane2001  If IR is to rich for your blood buy a used amber regen, those run under $100 now.  Power it with a chinese Linear PSU with a top quality regulator in it and it will improve the sound of your creamy gustard.

 

It wasn't too rich when it was $325. Even according to Uptone website, USB Regen is inferior to ISO Regen. At $655, I think I'll save my money and buy another DAC

 

[pkane2001]

36 minutes ago, Quadman said:

Lucky for you I have a X20u with level 1 mod for sale, without the AR, your wishes have been granted .  Seriously it does improve the sound of this Dac even the lowly AR.  I have not put the IR on the X20 as I don't want to pull my T+A from the music chain to do so.  BTW the level 1 mods also seriously up the SQ of the X20.  Have you done any of them?

 

No mods in my X20pro, it's all stock. I did upgrade the voltage regulators in the SU-1.

 

[pkane2001]

34 minutes ago, Superdad said:

a) It is the combination of two SMPS units (the Mean Well and the one in Amir's AP analyzer) which are creating the extra spikes way down;

b) Most people (in our market) do not run their DACs into preamps/poweramps that use switching power supplies.  For them there would not be the added spikes when using the Mean Well since there would be no direct interaction between it and the downstream component's PSU.

c)  But the lesson there is that having multiple SMPS in a system is undesirable.

d) If he powered the ISO REGEN from a battery (or our LPS-1) even all that would disappear.  

 

Alex, it would help if you could demonstrate any or all of these by something other than handwaving. A measurement to support these claims would be really great, as none of these are particularly obvious or can be deduced from just looking at what Amir has posted so far.

 

37 minutes ago, Superdad said:

A measurement system becomes part of the system.  Especially when measuring very low level noise.

Not speculation, just electrical facts.  Amir is the one with the AP analyzer--he should sort it out. 

 

The AC spikes were actually pretty high level at 20-30dB above background, hardly very low level. Sorry, but it's speculation because you have not provided any evidence to back it up other than your say-so. 

 

[pkane2001]

56 minutes ago, esldude said:

http://audiosciencereview.com/forum/index.php?threads/uptone-iso-regen-review-and-measurements.1829/page-10#post-46627

 

You can read in the above post and the next few posts additional testing done.  Including the excellent suggestion (imo) of using a 70 hz power supply to see which device is the source of various PS related signals. 

Essentially, with a laptop on battery, with an adjustable lab supply at 70 hz, with a USB cable wonky enough and long enough using 3 connected together it begins causing issues, the ISO Regen appears to be the source of the 60 hz related increase in the noise floor. It appears unable to help the clock of the receiving DAC 'clock' better.  Etc. etc.  Please do read the posts for details.

 

I would say the only remaining choices would be an isolator on the Regen, or everything else or use a better power supply.  Using a better power supply would net you the same result with at least the Behringer as not using the Regen.  Which makes it all seem rather pointless to use the Regen.

 

Looks like Amir performed the test I had suggested with different frequency power source. I don't see how any of the theories about AC leakage loops through multiple SMPS and/or common in-wall wiring can still be used to explain the AC noise caused by Meanwell supply with ISOR.

 

@Superdad, if you are still reading this, it would be a good idea for you or John to try to duplicate these results, and if confirmed, pick a better power supply that doesn't cause as much noise at the DAC. You don't need an AP Analyzer to get these measurements done (the noise is really at a high level). A good quality ADC and some free software would work to see if the AC noise is present or not.

 

[pkane2001]

@Superdad, please give up on this line of argument. Your latest theory on ASR has already been refuted:

 

Quote

This is just as predicted. It just happens that the 22W Mean Well (which of course exhibits larger excursions due to its size) is reinforcing with the leakage currents of your AP analyzer. If you can turn the plug around of either the Mean Well or the AP (just one, not both), then you will see a decrease in the amplitude of the spikes.

Amir tested with the  Meanwell PS plugged into a 70Hz power source, while AP was plugged in to 60Hz source. There's no reinforcement possible. And still, noise injected by Meanwell remained  at a large level of over 30dB. The only AC-related noise was produced by 70Hz  Meanwell, and not by AP (which would've been seen at 60Hz).