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

[scan80269]

I mentioned previously that I don't believe USB regenerators are panacea.

 

Some DACs (not just expensive ones) can clearly be immune to upstream USB crap, and some USB sources can be clean enough that a USB regenerator delivers no incremental cleanup.

 

For example, my Auralic Aries Femto & Vega DAC combo has not improved SQ wise by inserting either Amber REGEN or ISO REGEN, even with LPS-1 powering either.  I listened hard with both my headphones setup and a bi-amped time-aligned speaker setup at my friend's venue and we concluded the REGENs delivered no sonic improvement.  This Auralic gear apparently left nothing for ISO REGEN to clean up further.

 

However, with a different setup: a fanless NUC PC driving my Holo Audio Spring L3 DAC, the same ISO REGEN + LPS-1 made highly discernible differences, particularly in vocal sibilance.  I did not have to listen hard at all.

 

So in reality, the effectiveness of a USB regenerator can depend on both the upstream USB source and the downstream DAC.  Many user reports posted here on CA have essentially attested to this.

 

[Quadman]

@Imitche and I use the S11 to power my IR and a DIYinHK PSU to power my AR which is now located at my PC and feeds the IR at the dac.  That is a really nice PSU it made a very big sonic difference powering my buffered B1 preamp compared to a Teddy Pardo unit I was using.  I would easily recommend folks use a S11 instead of the meanwell, but the S11 is DIY.  So basically the cost of the Dac is the cheapest item in your digital chain, wow, just a observation nothing derogatory meant.  It continues to amaze me how just a few hundred $ can really improve your digital sound, whereas in the analog domain a few hundred $ won't get you squat.

[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

 

[scan80269]

Hey, I just realized what Amir's current measurement setup is great for: quantifying the AC leakage contribution of specific power supplies!

 

Re: the graphs in post #108 in the ASR thread, the amplitude differences in the bumps at 60Hz & harmonics between the red and yellow plots represent the contribution to AC leakage by the Mean Well SMPS.  By replacing the Mean Well with another power supply to power the ISO REGEN, the measurement can reveal the delta from the yellow baseline for that power supply.

 

Granted such measurements are looking at all the contributors to AC leakage in the system as a whole (an AC leakage loop requires at least two AC-connected power supplies, among other things), it is the differences in measured amplitudes that are revealing of the AC leakage nature of a power supply, as varying only that power supply in the entire measurement setup represents a control experiment.

 

[lmitche]

24 minutes ago, Quadman said:

@Imitche and I use the S11 to power my IR and a DIYinHK PSU to power my AR which is now located at my PC and feeds the IR at the dac.  That is a really nice PSU it made a very big sonic difference powering my buffered B1 preamp compared to a Teddy Pardo unit I was using.  I would easily recommend folks use a S11 instead of the meanwell, but the S11 is DIY.  So basically the cost of the Dac is the cheapest item in your digital chain, wow, just a observation nothing derogatory meant.  It continues to amaze me how just a few hundred $ can really improve your digital sound, whereas in the analog domain a few hundred $ won't get you squat.

There are two guys in California that will make a complete SIgma 11 power supply.  The builders are listed on this page:

http://www.amb.org/audio/sigma11/ 

Luckily I had a friend populate the regulator boards and I later did the integration with the toroid, connectors, heatsinks and cases.

 

Yeah, I figure I'll hang on to the IFI microIDSD until it becomes a bottleneck to future improvements.  So far, it keeps getting better tweak after tweak. I bought it to experiment with DSD512.  Little did I know how good it was with Hqplayer.

 

The microIDSD BL really shines with the USPCB, IR and Lush cable in place.

[firedog]

1 hour ago, scan80269 said:

One of the disputes here is whether Amir's graphs are representative of what the ISO REGEN is supposed to do, as claimed by its manufacturer.

 

Being a USB regenerator, ISO REGEN is intended to clean up the USB signal going from source to DAC.  From measurements perspective, the measurements should be focused on quantifying the USB signal quality differences at both ends of the device.  In this regard, I have to say the eye diagrams UpTone posted for USB signals entering and exiting an ISO REGEN are highly relevant.  Crappy measured USB signal coming from source (entering ISO REGEN) converted to clean measured USB signal (exiting ISO REGEN) going to the DAC.

 

Amir's work & conclusions on ISO REGEN are not unlike doing a smog check on a new car, then using the measured results to refute the car manufacturer's claim of engine fuel efficiency.

 

Uptone specifically claims that the USB cleaning done by the IR "makes the music sound better", not just that the USB output of the Regen is cleaner than what went in. 

 

If such devices make the music sound better, the only way they can be doing so is by resulting in a better sounding output from a USB DAC, than the output from the same DAC with no IR in the chain. If the output of the IR is cleaner, but this output has no effect on the the output of the DAC, then what is the point of the IR?

 

So this would logically need to be measured at the DAC, not at the Regen. 

 

Then the question becomes, do we know what to measure at the DAC and are we capable of measuring it? And secondarily, is Amir measuring the right thing and does he know how to measure it properly?

 

[Quadman]

24 minutes ago, pkane2001 said:

I think I'll save my money and buy another DAC

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?

[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.

 

[jabbr]

2 hours ago, scan80269 said:

One of the disputes here is whether Amir's graphs are representative of what the ISO REGEN is supposed to do, as claimed by its manufacturer.

 

I really think the graphs should be taken as standalone data, they are not applicable to every situation. We see that in one case, the regen cleaned up the spectrum in a pattern that I associated with reduced close in phase error. This doesn't mean that everything in the DAC has to do with this, nor that the regen is the only way to improve DAC phase error! Why would it?

 

I think this info is great because it does demonstrate that -- at least in one case -- USB SI has an effect on DAC phase error. There are other "things" like leakage current, that could be investigated in a different fashion. There are many different measurements that could be taken, including with equipment superior to the AP e.g. if very close in phase error measurements were desired.

 

So in any case we should add these graphs to the collection of available data, rather than necessarily draw overarching conclusions -- in the same way that other measurements have seemingly shown the regen to be inferior -- again a single graph with a single setup is always prone to artifacts from the testing environment which is why drawing major conclusions is difficult and should only be done very cautiously.

 

I would prefer to say "objective evidence" rather than "objective proof" in almost all cases.

[plissken]

6 minutes ago, jabbr said:

USB SI has an effect on DAC phase error.

 

I don't think the case for that has been made. We don't know what the Eye Pattern of the computer looks like for starters.

 

2nd it could be the voltage re-regulation on the ISOR that is improving the Modi 2.

 

There are still a lot of variables to address.

[jabbr]

19 minutes ago, plissken said:

 

I don't think the case for that has been made. We don't know what the Eye Pattern of the computer looks like for starters.

 

2nd it could be the voltage re-regulation on the ISOR that is improving the Modi 2.

 

There are still a lot of variables to address.

Fair enough. 

[wwaldmanfan]

2 hours ago, scan80269 said:

What was your USB source?

 

As per my signature, my source was the 2012 MBP  connected through a Kimber Kable Cu USB cable and the UpTone hard adapter.

I also tried the REGEN on my headphone rig, as listed below, with a Wireworld UV7 USB cable between my iMac and the REGEN. I may have heard an improvement through my headphones with the $500 Parasound DAC, but can't say I'm sure.

[wwaldmanfan]

1 minute ago, wwaldmanfan said:

 

 

[Superdad]

17 hours ago, plissken said:

The 60 Hz mains AC leakage noise isn't there with the AP in the loop though. Again, Amir and BE17 pointed this out: The AP for all intents and purposes is just another piece of audio gear.  It is what it is and no matter the amount of swinging away you want to do is going to change that fact. 

 

Been VERY busy since returning from my trip Sunday night (100+ e-mails to reply to just since Thursday?  I think the squabbling here is good for business!). So I am just now catching up with this circus.

 

Can't believe you guys are still missing the point and still arguing over an optional $10 power supply!  

So let's try this again:

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) Amir's graphs clearly show that even with direct USB connection (no ISO REGEN)--of his desktop PC (with SMPS) to his DAC>>AP--there is still plenty of leakage current noise.  So the particular interaction between his particular PC SMPS and the AP's PS is not terrible, so what?  It will vary greatly from PC to PC.  But the lesson there is that having multiple SMPS in a system is undesirable.  Again, most people don't, and in fact a lot audiophiles use computers/streamers with linear supplies.

 

d) Even any AC-connected linear supply is going to have some leakage and will interact with the higher leakage from an SMPS.  Take a look at Amir's graph when his "lab" supply is used--what you see remaining is the leakage of his AP interacting with his lab supply.  If he powered the ISO REGEN from a battery (or our LPS-1) even all that would disappear.  

 

 

So you guys should stop blaming the optional $10 supply ($15 with the 3-wire AC cord always included).  It takes two supplies to form a leakage loop.  Maybe Amir should ask AP why they don't build a proper, low-leakage LPS into their $25K test equipment!

 

An for heavens sake, look at all the wall warts that come with so many other products.  I don't see anyone screaming about those (except Amir when he encountered the very same issue during his testing of the microRendu with its optional iFi iPower SMPS wart; he made a mountain out of a molehill then as well). Every system has AC leakage currents running through it.  Deal with it--or use batteries, our UltraCap LPS-1, or a fully integrated, leakage-free unit like Vinnie Rossi's LIO (preamp/DAC/power amp--all on ultracapacitor PS).

 

 

16 hours ago, plissken said:

So now additional money beyond the $325 HAS to be spent not to get the problems with the included SMPS. Makes you wonder how much validation, if any, was done.  Why even include a 3rd party SMPS when you have all the design chops in house to build a straightforward linear 5v .5 amp power supply. That would cost $10 in a BOM. 

 

Ignoring your usual sniping (about "validation"):  See above points a) thru d).  And show me a $10, 1A LPS.  There are plenty of Chinese built LPS boxes available on eBay for $30-60, but none that can be sold worldwide with certifications.  Export is more than half our business and the Mean Well units have certificates valid in about 60 countries.

And again, people are free to add their own supply, use batteries, or buy our ultimate piece, the UltraCap LPS-1.  

 

16 hours ago, pkane2001 said:

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.

 

See d) above.

 

15 hours ago, pkane2001 said:

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

 

The hundreds of people who are thrilled with sonic result of inserting the ISO REGEN do not seem to have a problem with their "sighted listening" (isn't that an oxymoron?  and maybe offensive to the blind).

 

8 hours ago, plissken said:

The AP is a piece of audio gear so the argument can be made it's meant to represent a typical setup.

 

See b) above.

 

Quote

Alex was asked if he would do his own bias controlled evaluation. He said he would and then he disappeared from WBF immediately after Amir said he would fly out. I would still like to see this take place. 

 

Two years later and you are still misconstruing the interaction as an invitation to Amir.  It never was.  (Someone asked if I could tell the difference with the USB REGEN in a blind test; I said "Sure, any day of the week--in my system/room with my music."; Amir then said he would hop on a plane.  If you said you were a good cook and could tell how much salt was added to your meal, does that mean I am invited to your house to have you prove it to me?)

 

And for those who think Amir does not have some sort of agenda against John and me:  I see that just yesterday he continued his passive-agreessive campaign against us (much to the delight of his followers--I could hear Sal1950 squeal all the way across country) by posting my LinkedIn profile and making specious claims about John such as: "John has never used an audio analyzer and is not familiar with the signal processing concept here so makes a bunch of assumptions."

 

WTF?!

 

5 hours ago, pkane2001 said:

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.

 

See a) and d) at top.  A measurement system becomes part of the system.  Especially when measuring very low level noise.

 

Quote

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.

 

Not speculation, just electrical facts.  Amir is the one with the AP analyzer--he should sort it out.  But his agenda and ego might prevent him.

 

 

5 hours ago, jabbr said:

Lab power supplies are typically floating which reduce the issues with leakage currents (to the extent that the floating supply is not ground coupled by parasitic capacitance)

 

Reduced but not eliminated.

 

5 hours ago, plissken said:

I have to again point out that it's not a manufacturer showing this but someone with some skepticism showing this. But somehow the messenger is getting some backlash over it.

 

If an auto-body paint guy posts ultra-close-up photos of the factory paint of a Mercedes showing orange-peel--and then rants about it o the internet--should Mercedes spend their time arguing with him?  Orange-peel is a fact of product paint jobs.  Get a hand-rubbed custom job if you don't like it.  But don't tell us the rest of the car is shit because of it.

 

4 hours ago, pkane2001 said:

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.

 

Again, everyone has plenty of less expensive options for power supplies.  And none of Amir's measurements have anything to do with the sonic efficacy of our product.  

Look no further than his test-bench perfect measurements of the $70 Behringer DAC:  If that piece measures so well, then why are audiophiles the world-over not rushing to replace their MSB, T+A, PS Audio, and Chord DACs with it?

Amir says it sounds great to him.  Should we all fall in line and believe?  Well since he also posted that he has had a terrible time figuring out how to operate HQ Player and that he does not hear any differences between its many filter options, I'm going to suggest that he stick to the bench and not dispense advice on the SQ of equipment.

 

 

2 hours ago, scan80269 said:

Hey, I just realized what Amir's current measurement setup is great for: quantifying the AC leakage contribution of specific power supplies!

 

Re: the graphs in post #108 in the ASR thread, the amplitude differences in the bumps at 60Hz & harmonics between the red and yellow plots represent the contribution to AC leakage by the Mean Well SMPS.  By replacing the Mean Well with another power supply to power the ISO REGEN, the measurement can reveal the delta from the yellow baseline for that power supply.

 

Granted such measurements are looking at all the contributors to AC leakage in the system as a whole (an AC leakage loop requires at least two AC-connected power supplies, among other things), it is the differences in measured amplitudes that are revealing of the AC leakage nature of a power supply, as varying only that power supply in the entire measurement setup represents a control experiment.

 

Not really Sam.  John has explained (and measured on his bench) that every combination of power supplies will result in a unique spectrum of leakage current loop patterns.  And some supplies have extremely unique leakage signatures (the iFi iPower has a crazy unusual pattern).

And, as a reminder to everyone, AC leakage (traveling over system DC connections and not just ground lines) is not the same as power supply output noise/ripple.

 

Lastly, someone (scan or jabbr) mentioned that when they have to use an SMPS they prefer a lower-leakage medical version they linked to.  Mean Well makes those too, but the reason we do not offer those instead is that while the better ones have about 1/10th the leakage, they always have C8-style 2-prong AC cordage.   That causes problems for export (I won't get into all the details here), and while there are even some low-leakage "medical" wall-warts with interchangeable plugs, they have some drawbacks and also become pricey.  This is all mostly a non-issue.  The majority (60%) of ISO REGEN buyers choose to either omit the Mean Well SMPS from their order or purchase it as a bundle with the UltraCap LPS-1.

[esldude]

4 hours ago, lmitche said:

After playing with CA for three+ years I think of the entire digital side, PC, storage,  USB chain, DAC, upsampling and control software and power supplies as a single unit where the individual components are designed to work together. Everything seems to matter.

 

All together I have $2500 to $3000 in an audio source that competes with the best turntables and CD players in the world.  Not too bad. Plus it can be upgraded as further innovations become available. And I have no need to buy an expensive preamp.

What if you could do the same for $79?  I am not saying you can, but would you believe it?  I actually think you can for about $500.  But not as long as you let your hearing be swayed by knowing what you are listening to.  Would you believe your own ears, and only your ears?

[Quadman]

7 minutes ago, esldude said:

Would you believe your own ears, and only your ears?

 

At DSD512 in my very familiar listening room, yes I am confident.

 

[esldude]

2 hours ago, firedog said:

Uptone specifically claims that the USB cleaning done by the IR "makes the music sound better", not just that the USB output of the Regen is cleaner than what went in. 

 

If such devices make the music sound better, the only way they can be doing so is by resulting in a better sounding output from a USB DAC, than the output from the same DAC with no IR in the chain. If the output of the IR is cleaner, but this output has no effect on the the output of the DAC, then what is the point of the IR?

 

So this would logically need to be measured at the DAC, not at the Regen. 

 

Then the question becomes, do we know what to measure at the DAC and are we capable of measuring it? And secondarily, is Amir measuring the right thing and does he know how to measure it properly?

 

This is the real question.  I don't doubt the cleaning up of the USB signal by the Regen.  I do doubt that it makes for better sound.

 

In the case of the measurements, we have one DAC very susceptible to what is on the USB and the Regen cleaned it up.  We have others that seem relatively un-bothered by the USB quality.  Some look the same at the output with the Regen and some show a bit of extra 60 hz components with it (these being too low to be audible).  So it would appear you don't need the Regen.  So what is useful are measurements of which DACs are in need of having the USB very clean. 

 

I am a bit hazy on the details, but I seem to remember mansr posting perhaps some USB or it might have been SPDIF coax cables of very long lengths like 100 ft, showing the eye pattern was all messed up, and yet his DAC put out just as clean a signal either way.  DACs that don't need this cleaning are a good place to spend money it seems to me.  And it seems some of those cost no more than the Regen. 

[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. 

 

[Quadman]

4 minutes ago, pkane2001 said:

pretty high level at 20-30dB above background

 

Yet still -112 db below reference, inaudible.

 

Since it is obvious Alex does not have an AP, nor John, why doesn't Amir use an isolation transformer on the AP and battery only on his MBP laptop and redo the measurement to humor us subjectivists.  Make sure to use the meanwell on the IR this way.

[plissken]

47 minutes ago, Superdad said:

 

Been VERY busy since returning from my trip Sunday night (100+ e-mails to reply to just since Thursday?  I think the squabbling here is good for business!). So I am just now catching up with this circus.

 

Can't believe you guys are still missing the point and still arguing over an optional $10 power supply!  

So let's try this again:

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;

 

 

In the presence of a circuit there is always going be this potential. The question is 'how much'. There is also another SMPS upstream of the ISO.R: The supply in the computer. 

 

So why is it only combination of the AP and the MeanWell? Downstream is also the power supply of the laptop that is used to control the AP. 

 

From your site: 

 

The ISO REGEN is an active device that needs to be powered: On the upstream/input side of the isolator “moat,” power is provided by the 5VBUS of the USB cable from your computer; on the downstream “clean” side of the isolator—where most all of the “magic” happens—an external power supply in the 6~8 volt DC range is required.

 

So what is the "moat" doing in your ad copy? If you know there are going to be other power supplies on the downstream side of the ISOR that would represent these low impedance loops why wasn't the engineering consideration taken for this? 

 

47 minutes ago, Superdad said:

 

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.

 

I have no idea how to even respond to your Johnny Carson 'The Great Carnak" routine. What exactly are you thinking they are running their DAC's into? 

 

47 minutes ago, Superdad said:

 

c) Amir's graphs clearly show that even with direct USB connection (no ISO REGEN)--of his desktop PC (with SMPS) to his DAC>>AP--there is still plenty of leakage current noise.

 

Define 'plenty of leakage current noise'. Amir says what your product does is not audible. Then we look at USB powered DAC of $79 having 20dB improved 60Hz mains performance without ISOR. I'll take 20dB improvement for $0 cost for $500 Alex. 

47 minutes ago, Superdad said:

So the particular interaction between his particular PC SMPS and the AP's PS is not terrible, so what?  It will vary greatly from PC to PC.

 

Great. I look forward to your measurements. So we can stop with the USB Eye Pattern and move onto meaningful data: The DAC output. 

 

 

47 minutes ago, Superdad said:

 

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

 

Great. I'll start with not using one of yours. 

 

47 minutes ago, Superdad said:

 

d) Even any AC-connected linear supply is going to have some leakage and will interact with the higher leakage from an SMPS.  Take a look at Amir's graph when his "lab" supply is used--what you see remaining is the leakage of his AP interacting with his lab supply.  If he powered the ISO REGEN from a battery (or our LPS-1) even all that would disappear.  

 

Where is this leakage and where are your measurements of a battery or LPS-1. 

 

47 minutes ago, Superdad said:

 

So you guys should stop blaming the optional $10 supply ($15 with the 3-wire AC cord always included).  It takes two supplies to form a leakage loop.  Maybe Amir should ask AP why they don't build a proper, low-leakage LPS into their $25K test equipment!

 

Because the AP is accurately showing the lack of 60Hz fundamental and the spurie even/odd harmonics with USB bus power. 

 

47 minutes ago, Superdad said:

 

An for heavens sake, look at all the wall warts that come with so many other products.  I don't see anyone screaming about those (except Amir when he encountered the very same issue during his testing of the microRendu with its optional iFi iPower SMPS wart; he made a mountain out of a molehill then as well). Every system has AC leakage currents running through it.  Deal with it--or use batteries, our UltraCap LPS-1, or a fully integrated, leakage-free unit like Vinnie Rossi's LIO (preamp/DAC/power amp--all on ultracapacitor PS).

 

Have to do something about the fridge, fluorescent lights, dimmers, and all the other PSU's in the house. 

 

47 minutes ago, Superdad said:

Two years later and you are still misconstruing the interaction as an invitation to Amir.  It never was.  (Someone asked if I could tell the difference with the USB REGEN in a blind test; I said "Sure, any day of the week--in my system/room with my music."; Amir then said he would hop on a plane.  If you said you were a good cook and could tell how much salt was added to your meal, does that mean I am invited to your house to have you prove it to me?)

 

Only if you agreed to bias controlled  tasting. Which you did. 

 

[plissken]

8 minutes ago, Quadman said:

 

Yet still -112 db below reference, inaudible.

 

Since it is obvious Alex does not have an AP, nor John, why doesn't Amir use an isolation transformer on the AP and battery only on his MBP laptop and redo the measurement to humor us subjectivists.  Make sure to use the meanwell on the IR this way.

 

So I should be fine with an audiophile product that promises a 'moat'  for the 5v input. And increases a noise metric by 20-30dB?

 

 

[mansr]

20 minutes ago, Quadman said:

Yet still -112 db below reference, inaudible.

What happened to the "everything matters" mantra?

[plissken]

7 minutes ago, mansr said:

What happened to the "everything matters" mantra?

 

LOL. Good one. Everything matters until it doesn't. 

[Quadman]

11 minutes ago, plissken said:

So I should be fine with an audiophile product that promises a 'moat'  for the 5v input

 

No you shouldn't,  but until we totally 100% eliminate Alex's theory I cannot 100% feel confident in Amir's result and blame 100% on the IR/Meanwell combo.  There is interaction between everything in the test path.  Even AP says for best results all chassis grounds should be connected to analyzer, since that is next to impossible with meanwell the next best is to isolate it away from the meanwell in my opinion.

[Quadman]

Yep everything does matter including my ears and their reaction to the music I play, I am not a 100% measurement only guy, but I do take lots of measurements and I also use my ears.