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Uptone ISO Regen Review and Measurements

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amirm

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Thread Starter #361
And why are you still going on about the basic facts of SMPS?

And by the way, quite a few DACs with built in power supplies are using SMPS units (with leakage of one degree or another).
I was asked directly so I responded.

And sure, you can use switchmode supplies in audio. As I explained there are other topologies such as resonant/quasi resonant that don't require such extreme EMI filtering that causes the AC mains leakage.

Also, since they are not selling a power supply with a long DC lead, they don't have to face that situation that you do with a wall-wart. The "antenna" there is much shorter and only the entire DAC needs to be certified, not the power supply itself.

It has been your position that all switchmode power supplies are the same/use Y capacitors this way. Not mine.
 
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Really? 99% of DACs and preamps don't have balanced XLR outputs and inputs? Where did you pull that statistic from?
Its not the question of weather the DAC has 99% balanced XLR or not. If your preamp is single ended, then how will the balanced XLR connection from your DAC help ? I hope you understand this simple fact :p

What Amir is claiming is actually true that most of the time, audiophiles have single-ended system. How many tube preamp and amps are full balanced design ?
 

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Its not the question of weather the DAC has 99% balanced XLR or not. If your preamp is single ended, then how will the balanced XLR connection from your DAC help ? I hope you understand this simple fact :p

What Amir is claiming is actually true that most of the time, audiophiles have single-ended system. How many tube preamp and amps are full balanced design ?
Good grief. I could say it's sunny and the sky is blue and you guys would argue about that until it was dark. ;)
 

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Well that's pretty funny since the Intona does not have a power supply. It is 100% bus-powered. And it uses a DC-AC switching converter to get the 5V across the moat through a transformer, then on the other side diodes and a linear regulator with 150 times the noise of the LT3042 (world's lowest noise regs: RMS Noise: 0.8μVRMS (10Hz to 100kHz), spot noise: 2nV/√Hz at 10kHz, PSRR: 79dB) that we use 5 of in the ISO REGEN. Plus, from a standard USB 2.0 port the Intona can not provide more that about 300mV of bus power, well short of USB spec (whereas the ISO REGEN can provide up to 1A for devices that need it.) And they put their cheap clock on the dirty side of the "moat."

You personally may not be able to hear the quality of the Crystek CCHD-575 that we splurge on, but I and lots of other people can. Take a look at the recent upgrade offered to microRendu users. Only change to the board (V1.3 to V1.4) was the replacement of the CCHD-3391 with the CCHD-575. And hundreds of users are thrilled with the difference.

Hopefully soon we will be able to produce the graphical proof you all are so desperate for to show you that upstream stuff really does make a difference in the output of the DAC. It will be from a system that reveals more that the general purpose AP.
While that's great, you could do controlled listening tests NOW. There's no need to wait and invent a special machine.

You constantly refer to sighted evaluations being the corner stone of your design process, it seems basically like you guys listen and if you think it's better you cement a theory and validate a design choice.

Is that what you really do or am I reading a false into your words?

If as it seems ( as you have mentioned it here and elsewhere a few times) , you do make design choices or at least validate them by sighted listening why not invest in controlled listening tests ?

I just struggle to understand why you avoid that, the only reason I'm left with is fear. Turkeys don't vote for Christmas and your not about to risk voluntarily lampooning your products and destroying the brand you have established by submitting them and yourselves to controlled listening tests in the fear it all will fail.

I can understand that 'fear' if indeed that's what's going on here, I felt that when I was challenged about the choices I made in buying my hifi, I'd spent vast sums of money ( over £70/80 thousand in 5 years) and the idea I had deceived myself via my sighted listening and could look a fool when it all came to light was distressing.

I have the multi thousand £ power cables and IC's , the mains filters , ground boxes, the CDP/DAC that cost well over £10000 , by bee quantum things, the cryogenically treated mains spur etc etc etc

All chosen by me after sighted listening and by reading glowing customer reviews from folks ( the same folks who leave feedback for your products) .

Iv ran back and forth from the listening chair after moving my rack forward a inch or putting some special isolation device under my amps eagerly listening out for differences , and I heard a ton of differences .. mostly negative ones , that reassured me I was not a fool. I was hearing the truth because everything made a difference but often not a good one. If I'd always heard a benefit then obviously I'd be fooling myself so I thought at the time.

Iv learnt that many of the conclusions I drew were wrong, I was faulty and my subjective listening impressions were the subject of variables far beyond my understanding and not always pertaining to the physical electronics or the little changes I had made.

It's all rather embarrassing looking back and I know the majority of audiophiles are still under the illusions I was back then .

This is why it's so concerning to read that you are relying on this sighted subjective method in order to develop and validate your products.
 

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Good grief. I could say it's sunny and the sky is blue and you guys would argue about that until it was dark. ;)
I have to agree, while I use single ended now I used to use balanced that's all anecdotal, this is a objective forum so amirs guesstimates of 99% are not valid.

I'd go further and say they are unsabstanciated bollocks :D

To try and justify them makes us all look daft ( that's my job so hand off ) like we are just making shit up now to try and pin on you.

Well I am not down with that! :cool:
 

Thomas savage

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I said 99% of people don't use balanced interconnects. Even when the DAC for example may have such a connection, they opt instead to use unbalanced connection because their amp is that way.

What do you think the stats are? What DAC do you and John personally use and is it with balanced connections?
Stop digging a hole! You quoted a statistic with no evidence to back it up. Just retract it and move on!

:p:D
 

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Well that's pretty funny since the Intona does not have a power supply. It is 100% bus-powered. And it uses a DC-AC switching converter to get the 5V across the moat through a transformer, then on the other side diodes and a linear regulator with 150 times the noise of the LT3042 (world's lowest noise regs: RMS Noise: 0.8μVRMS (10Hz to 100kHz), spot noise: 2nV/√Hz at 10kHz, PSRR: 79dB) that we use 5 of in the ISO REGEN. Plus, from a standard USB 2.0 port the Intona can not provide more that about 300mV of bus power, well short of USB spec (whereas the ISO REGEN can provide up to 1A for devices that need it.) And they put their cheap clock on the dirty side of the "moat."

You personally may not be able to hear the quality of the Crystek CCHD-575 that we splurge on, but I and lots of other people can. Take a look at the recent upgrade offered to microRendu users. Only change to the board (V1.3 to V1.4) was the replacement of the CCHD-3391 with the CCHD-575. And hundreds of users are thrilled with the difference.

Hopefully soon we will be able to produce the graphical proof you all are so desperate for to show you that upstream stuff really does make a difference in the output of the DAC. It will be from a system that reveals more that the general purpose AP.
Yes I know its bus powered, and I know the topology - THATS THE POINT!

You have cited the Intonas PSU design topology to imply its a problem when clearly and demonstrably it is not.

Your specmanship demonstrated here also shows how much you rely on "dazzle with numbers" (to the technically ignorant) as opposed to meaningful engineering. The Intonas power supply is perfectly adequately quiet. They have no problems in publishing the data. Their PSU methodology means they dont run into the problems yours creates.

So below we see that at 1kHz the noise level is 0.000000775 V rms (0.775uV). Can you get your spectrum analyser out and take the same data for the regen so we can compare? Then, more pertinently, if the Regen is lower how that translates into an improved performance at the DAC output.



Can you explain what you mean by "300mV of bus power". Doesnt make any sense to me. With regards to supply current, again Intona have no problem publishing the specs, and your statement is wrong. Only a bus powered DAC with inadequate supply regulation (and non USB spec compliant) would have an issue with this, it falls within the USB 5 V spec.



Regarding graphical proof, you said this about the original Regen, what 2 years ago? Still waiting............

Regarding what I can and cannot hear, you havent actually presented any evidence from controlled subjective testing that anyone else can hear the difference.
 
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First, let me give the punchline that Alex (likely his designer John) later on have agreed that his hypothesis was wrong. Please see: http://www.audiosciencereview.com/f...view-and-measurements.1829/page-15#post-46792

Here is the much longer answer.

Switchmode power supplies due to their nature of turning on and off, create tons of electromagnetic interference (EMI). This switching noise starts at Kilohertz frequencies but goes way up to megahertz due to its high power and decomposition of a square wave (odd harmonics forever). In western world, such devices must limit this kind of interference or they are not legal to sell.

What is bad is that the radiofrequency energy actually comes out of the DC wire of the power supply! Even though the switching is before the isolation transformer, there is enough capacitance to let high frequencies to travel across that isolation barrier and as such, make the DC wire as an antenna radiating everywhere.

Turns out there is a very cheap solution to the problem. You put a capacitor from the output of the power supply to its AC input. The impedance of the input is pretty low for high frequencies and as such, it works to substantially reduce the radiated energy.

Now, you don't want that capacitor to ever fail short because if it does, it will connect the AC input to output representative massive risk of shock/death! For this reason, special safety capacitors called "Y" (and "X") capacitors are used here which in failure mode, become open (there is a film in there that burns through). So if there is an incoming surge on the AC line, all that happens is that you lose your EMI reduction above.

Now you know why the "y capacitor" reference has been used time and time again.

Here is the issue with the Y capacitor though. It not only takes the output noise and dumps it in the input, but also works in reverse, allow some (small) amount of AC mains current to travel the other way onto the output of the DC power supply.

There are regulations on how much is allowed before there is a risk of shock. If you ever touch an appliance and you get a "buzz", that is the leakage current that is allowed. That is, it doesn't kill you so it is OK.

Problem we have in audio is that we have "single-ended" equipment, i.e. RCA Jacks. This means that the reference for the signal, i.e. what is "zero," is the chassis of the equipment. This is a bad architecture and the reason people sometimes get hum. Getting rid of that hum requires that we stop the current flow between the chassis of the two pieces of equipment. Because once it flows, it is indistinguishable from audio signal itself.

In the case of switchmode power supply as used in this context is that it is already anxious and ready to pump out AC current. By design, it is "leaking" current and it is doing so on the ground pin of the DC connector which becomes the ground of the audio circuits.

Wow. Are you with me still? :)

Now let's get into Alex's hypothesis that there is a switchmode power supply in the Audio Precision Analyzer and hence, it also contributes the same problem. The fundamental problem with that theory is that he doesn't know it is using a switchmode power supply for its operation. I don't either. But this becomes immaterial if you read further.

If you have read this thread fully, you will see that I tested sources powering my USB DAC like my main computer and laptop which too have switchmode power supplies. These supplies showed none of the AC leakage.

The reason they did not is because they have better designed power supplies than the $10 wall wart supplied here. Putting in the Y cap above is a hack, an effective one but still a hack. It allows the power supply to have lots of noise to start, and then tries to filter it. A better but more expensive solution is to use other power supply topologies that have far less noise (e.g. switch when the current is zero). To that end, if the AP has switchmode power supply, it too would be of highest quality by nature and not source of its own leakage.

Now, the theory that Alex/John put forward was even more complex than this. They were attempting to say -- poorly I might add -- that not only there was leakage in the AP but that it was adding to the ones contributed by their supply. Well, this was easy to test for as I have an AC power generator that lets me program its frequency. So I set that to 70 Hz and let the AP run at 60 Hz. That way, the AC leakage contribution would be different from each other. The result resoundingly showed the leakage to be entirely that of 70 Hz and hence, the power supply that came with Iso Regen:



It is true that if we had used balanced system, we would not worry about this. But 99% of the people are not. If your amplifier/pre-amp is connected to the DAC using RCA jacks, then you would see the exact the same leakage as my Audio Precision Analyzer sees.

Summary
Cheap switchmode power supplies employ filtering that by design creates AC current leakage. In typical unbalanced (RCA) audio systems that we use, we are highly susceptible to such leakage because it establishes the reference for our audio signal. As such, this leakage current travels all the way through the DAC and presents itself on its output.

Solutions are to use linear power supplies, avoid these devices if they present no other value, or much better switchmode power supplies.

None of this points to a flaw in the design of the test fixture that I am using. I am on purpose emulating what happens in real life.

P.S. Welcome to the forum. :)

Thanks for the explanation. It's very helpful to learn the actual measurements of audio products. Some companies are forthcoming with their specs, others not so much. Customer testimonial is often subjective for many reasons. It's nice to see testing other than someone's personal opinion.
 
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BTW, contrary to what you wrote, floated-secondary isolation transformers are quite safe. TV repairmen have been relying on them that way for safety for 70 years.
They do use them but you better know what you are doing or it could have catastrophic consequences. Here is a video from one of the top "repairmen" I know (and I used to be one for years, repairing all kinds of electronic equipment):


Here is another video on the same topic with directly addressing defeating the ground wire around 10:15 marker:


The right solution is an isolated differential probe. Anything else is a hack and potentially very dangerous. These are expensive and people take shortcuts but that doesn't make them right.

Regardless, point remains that you must not instrument a piece of audio gear different than the other way it is used. And here, unbalanced, isolated is the rule.
 
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Stop digging a hole! You quoted a statistic with no evidence to back it up. Just retract it and move on!

:p:D
Sounds like some people don't know the meaning of the phrase, "job security!" :D
 

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While that's great, you could do controlled listening tests NOW. There's no need to wait and invent a special machine.

You constantly refer to sighted evaluations being the corner stone of your design process, it seems basically like you guys listen and if you think it's better you cement a theory and validate a design choice.

Is that what you really do or am I reading a false into your words?

If as it seems ( as you have mentioned it here and elsewhere a few times) , you do make design choices or at least validate them by sighted listening why not invest in controlled listening tests ?

I just struggle to understand why you avoid that, the only reason I'm left with is fear. Turkeys don't vote for Christmas and your not about to risk voluntarily lampooning your products and destroying the brand you have established by submitting them and yourselves to controlled listening tests in the fear it all will fail.

I can understand that 'fear' if indeed that's what's going on here, I felt that when I was challenged about the choices I made in buying my hifi, I'd spent vast sums of money ( over £70/80 thousand in 5 years) and the idea I had deceived myself via my sighted listening and could look a fool when it all came to light was distressing.

I have the multi thousand £ power cables and IC's , the mains filters , ground boxes, the CDP/DAC that cost well over £10000 , by bee quantum things, the cryogenically treated mains spur etc etc etc

All chosen by me after sighted listening and by reading glowing customer reviews from folks ( the same folks who leave feedback for your products) .

Iv ran back and forth from the listening chair after moving my rack forward a inch or putting some special isolation device under my amps eagerly listening out for differences , and I heard a ton of differences .. mostly negative ones , that reassured me I was not a fool. I was hearing the truth because everything made a difference but often not a good one. If I'd always heard a benefit then obviously I'd be fooling myself so I thought at the time.

Iv learnt that many of the conclusions I drew were wrong, I was faulty and my subjective listening impressions were the subject of variables far beyond my understanding and not always pertaining to the physical electronics or the little changes I had made.

It's all rather embarrassing looking back and I know the majority of audiophiles are still under the illusions I was back then .

This is why it's so concerning to read that you are relying on this sighted subjective method in order to develop and validate your products.

Wow, that's a lot of straw-man arguments to say the same thing!

Our products--like those of virtually every other high-end manufacturer--are designed both on the bench and in the listening room. Ask 100 other designers--call Charlie Hansen, Paul McGowan, Conrad-Johnson, whoever--and they will ALL tell you that listening is a key component of production development. And we are talking down to small parts changes too.

Do any of them organize and conduct "controlled listening tests" that would satisfy all you DBT-devotees? No! They are all to busy doing real work, and their systems are good enough and known well enough that with their own reference recordings they can make their determinations very quickly. Single-variable tests. A/B/A/B.
Good grief it took 15 seconds for me to pick which of the hub chips we preferred and separately to hear how clearly better--and worthwhile to use--is the Crystek 575 clock.

I know all this is hard for people who have not spent decades intimately involved in the design process of fine audio components to accept this fact. But next time you are at an audio show, talk to a few engineers about their process.
 

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Yes I know its bus powered, and I know the topology - THATS THE POINT!

The Intonas power supply is perfectly adequately quiet.
Can you explain what you mean by "300mV of bus power". Doesnt make any sense to me. With regards to supply current, again Intona have no problem publishing the specs, and your statement is wrong. Only a bus powered DAC with inadequate supply regulation would have an issue with this, it falls entirely within the USB 5 V spec.
Try again. Here is their own input current versus output current graph. As I said--and as they say--a computer USB 2.0 port delivering 5V at its max 500mA will allow the Intona to deliver only 300mA. If you have a device that needs say 400mA (typical with bus-powered DACs/headphone amps), then you are SoL because your computer is not going to give the Intona 600mA to do so.
And you can read about users having an issue with this in the real world. Along with computer/DAC recognition issues and intolerance of out-of-spec USB cables. Don't believe me. Read the forums. (And yes I have an Intona and tested it fully.)

USB_High_Speed_Isolator_EN copy.jpg
 

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Wow, that's a lot of straw-man arguments to say the same thing!


Good grief it took 15 seconds for me to pick which of the hub chips we preferred and separately to hear how clearly better--and worthwhile to use--is the Crystek 575 clock.

.
How do you know it wasnt the additional 60Hz mains spuria induced by the PSU that you liked?
 
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Thread Starter #374
I know all this is hard for people who have not spent decades intimately involved in the design process of fine audio components to accept this fact. But next time you are at an audio show, talk to a few engineers about their process.
It is true that controlled listening is rare to non-existent in high-end. What does exist however is engineering excellence. They massively overdesign gear which is fine. It does no harm and at any rate, their amplifier amplifies, their DACs convert digital to analog, etc.

Your device on the other hand doesn't do anything. It has no function and the little that it does, is to degrade performance of downstream device by injecting mains ac current and such. This is why the request for controlled listening test is much more valid than for high-end audio equipment manufacturers.

So it is not correct to put yourself in the bucket of high-end audio equipment makers. You are in digital tweak business and so far, selling on ideas and not performance that can be verified.
 

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They do use them but you better know what you are doing or it could have catastrophic consequences.
Actually, I and a lot of other people use "floated-secondary" isolation transformers for our audio gear. Not sure where all the paranoia about them comes from.

The right solution is an isolated differential probe. Anything else is a hack and potentially very dangerous. These are expensive and people take shortcuts but that doesn't make them right.
Yes, John has two of them. One is a very high-bandwidth, low-noise one. Even the accessories for it are expensive.

Regardless, point remains that you must not instrument a piece of audio gear different than the other way it is used. And here, unbalanced, isolated is the rule.
You may be unbalanced (I don't mean that personally, but whatever), but your test setups are not particularly isolated.
 

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Try again. Here is their own input current versus output current graph. As I said--and as they say--a computer USB 2.0 port delivering 5V at its max 500mA will allow the Intona to deliver only 300mA. If you have a device that needs say 400mA (typical with bus-powered DACs/headphone amps), then you are SoL because your computer is not going to give the Intona 600mA to do so.
And you can read about users having an issue with this in the real world. Along with computer/DAC recognition issues and intolerance of out-of-spec USB cables. Don't believe me. Read the forums. (And yes I have an Intona and tested it fully.)

View attachment 8162
Thanks for that, I wasnt aware it needed more than 500mA in to acheive spec, however I do challenge your statement that that a PC wont necessarily deliver more than 0.5 A and 400mA is typical. The ones I have measured are not that restricted..

So you consider an "out of spec" USB cable to be Intonas fault? Oh yes I have read the forums and there were some issues with xmos (due to an odd hS process IIRC) which were resolved.

OK, back to noise. Please explain why a lower noise supply will help, and what measurements you have taken to prove your theory.
 
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Your device on the other hand doesn't do anything. It has no function and the little that it does, is to degrade performance of downstream device by injecting mains ac current and such. This is why the request for controlled listening test is much more valid than for high-end audio equipment manufacturers.

So it is not correct to put yourself in the bucket of high-end audio equipment makers. You are in digital tweak business and so far, selling on ideas and not performance that can be verified.
How do you know it wasnt the additional 60Hz mains spuria induced by the PSU that you liked?
Oh for F's sake. Only about 30% of the people who buy our product use it with the Mean Well. You two just can't let go.

And as for Amir's lovely insults, go sling the same at the rest of the makers in this space.

Thomas: You wonder why ASR gets slammed for bias and nastiness? All that spinning and defense you put up (at CA yesterday) goes right out the window when your "partner" continues the smear.

I'm done here. Have way too many more worthwhile things to do with my time.
 
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Thread Starter #380
And as for Amir's lovely insults, go sling the same at the rest of the makers in this space.
There was no insult in there. My system produced audio with identical functionality with and without ISO Regen. If on the other hand I take out my high-end DAC, it stops working. This is what I was saying.

I still like to know if LPS-1 removes AC leakage. Does it?
 
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