Uptone ISO Regen Review and Measurements

[DonH56]

I like chocolate. Chocolate makes anything sound better. Doesn't seem to help the measurements much but I feel better when taking them anyway.

Edit -- Mental note: stay far, far away from Amir's RV!

 

[Burning Sounds]

Great thread, Amir.

It looks like the Oppo Sonica dac may be another one that might suffer from USB noise. Siegfried Linklwitz uses one and is currently using the artistic fidelity isolator/recl0cker (not inexpensive!) as subjectively he finds the music more engaging with the device in both his systems. He says "I am still surprised that it is needed in my systems. My primary source for sound is a notebook PC's USB port. The PC travels with me between the two LX521.4 systems in different locations. I thought a Sonica DAC would not benefit, but it does." He goes on to state: "This device points to problems with the digital data and spurious signal streams coming from the USB port of my PC. I will investigate this. The engineer in me wants an answer. "

I bought an Olimex USB isolator several years ago (for £25 from Farnell I think - I'm a true Yorkshireman ) and although I could not detect any difference using it with my Benchmark DAC1 or Audiolab MDAC it was functional in the sense that everything worked OK. However, my current dac, a Mytek ADDA8x192 does not like it at all and will not lock to a signal when the isolator is in place. The 8x192 uses the Swiss Rigisystems USB board.

 

[amirm]

Great thread, Amir.

It looks like the Oppo Sonica dac may be another one that might suffer from USB noise. Siegfried Linklwitz uses one and is currently using the artistic fidelity isolator/recl0cker (not inexpensive!) as subjectively he finds the music more engaging with the device in both his systems. He says "I am still surprised that it is needed in my systems. My primary source for sound is a notebook PC's USB port. The PC travels with me between the two LX521.4 systems in different locations. I thought a Sonica DAC would not benefit, but it does." He goes on to state: "This device points to problems with the digital data and spurious signal streams coming from the USB port of my PC. I will investigate this. The engineer in me wants an answer. "

It might but we would only know it if we measured it. Subjective observations abound about the benefit of these devices even though in vast majority of cases they are not doing anything function as the measurements of other DACs in this thread show.

Still, if he wants to be sure, ask him to send me the Oppo and I will measure and report back.

 

[Blumlein 88]

It might but we would only know it if we measured it. Subjective observations abound about the benefit of these devices even though in vast majority of cases they are not doing anything function as the measurements of other DACs in this thread show.

Still, if he wants to be sure, ask him to send me the Oppo and I will measure and report back.

This brings to mind that maybe it would be good for you to measure the ADC side of the Uphoria 204 HD Amir. If it performs well enough as verified by testing with an AP, it would have utility as a basic measuring device for audiophiles wishing to protect themselves from foolishness such as whether or not some add on really does anything at the output of audio gear or not.

 

[March Audio]

Your ill thought out debate points are what are getting you into trouble:

1. Your straw man argument about galvanic isolation: It's evidently not needed on a competent DAC as Amir showed that the on/off switch doing nothing for properly designed DAC's
2. Behringer 204HD, Mytek Brooklyn, iFi. Emotiva says none of their DAC's need it. Chord says none of their DAC's. Benchmark says none of their DAC's So we are effectively into 'the dozens'

Why don't you mention all dozens or hundreds of DAC's that have their output improved by galvanic isolation?

Jujinku, galvanic isolation can indeed be necessary but it depends on a number of factors as to whether it is an issue in any particular installation. You can get ground noise currents circulating modulated by digital noise. Some dacs are isolated so won't benefit from the device.

The problem is people assume they have a problem and imagine an improvement when they plug these devices in. Totally placebo in most cases
The galvanic isolation is more of a real issue than the "cleaning" of usb signals. I HAVE yet to see any evidence presented anywhere that cleaning usb signals has improved the output of any dac

 

[March Audio]

Galvanic isolation in the USB interface is great for stopping noise, but at the same time when used after the USB interface like in most DAC's that use it, it causes major jitter. So it's a catch 22. This is why using USB for audio sucks.

Best to use a premium Ethernet interface board with fiber optic Transciever input. The fiber optics offer 100% isolation. And with Ethernet the audio isn't clocked until the endpoint so jitter isn't a concern.

Can you provide some measurement evidence of this massive jitter caused by isolation?

 

[Mivera]

Can you provide some measurement evidence of this massive jitter caused by isolation?

The manufacturers of the GI chips specify the jitter right in their data sheets. This jitter is only a secret to folks looking for it from the analog outs.

 

[Blumlein 88]

The manufacturers of the GI chips specify the jitter right in their data sheets. This jitter is only a secret to folks looking for it from the analog outs.

So whether it is findable at the analog outs, how does jitter manifest itself? If the analog out doesn't change the sound doesn't either.

 

[amirm]

There is a parallel discussion thread on CA forum for discussions of information in this thread. Alas, I am banned from that forum and folks there don't want to come here. So I thought I address some of the points made there, specifically this one from member mmerrill99: https://www.computeraudiophile.com/...point-again-looks-for-the-music-in-the-noise/

To summarize, the point is being made that some types of "noise" may be difficult to instrument and see in fourier transforms I have been showing. As an example, a type of distortion called pre-echo which occurs in audio compression is explained and shown in this nice video:

In a nutshell, when there are transients, due to the way lossy compression works in using a block of audio for compression, any "quantization noise" is spread across that block/window. Think of taking some of the energy from the sound of a "tick" and spreading it before and after it. What is after is not very audible (temporal masking) but what is before can be although it requires trained ears to hear it at lower levels. The above video shows this in the case of highly compressed MP3 at 64 kbps with the result of "dirty" sound you get prior to transients.

This is all true. And it is also true that for detecting fidelity of lossy compression, we do not use measurements. Listening tests rule and of course they are conducted blind when it matters.

Merrill goes on to say: "One thing I mentioned before is that standard FFTs will not show dynamic noise fluctuations of this type so showing FFTs of the analogue output of a DAC is laughably flawed (guess who does this to "prove" these devices have no effect?)"

First forgive me for giving a bit of my resume but it is necessary here. For a decade I managed the signal processing group at Microsoft among others. We developed a number of lossy codecs such as WMA, WMA Pro, WMA Voice, etc. And I worked closer with this group than any other, routinely working to advance the state of the art and advancing fidelity of lossy audio compression. So the example given above is fully in my wheelhouse.

Now let's discuss the issues with the argument made.

First thing to note that if something changes in time domain, it absolutely shows up in frequency domain. The transform is bidirectional and it cannot be that you add so much pre-echo distortion and frequency domain (FFT) shows no difference. To show that, I went ahead and compressed a standard MPEG reference clip for lossy codecs, castanet, and encoded it into 64 kbps MP3. Pre-echo is very strong there as in examples Merrill shows. Here is the FFT spectrum of the original file (in red) and the 64 kbps MP3 (in yellow) overlaid on it:

At 64 kbps, MP3 has a limit of 12 Khz and see that in the sharp drop at that frequency. That is not material to this discussion. What is material is that at lower frequencies the two graphs do not at all look identical. The curves deviate as they should. The Fourier transform works on a window of time and it easily captured the differences in the original and compressed MP3 with pre-echo.

Interestingly enough, the lossy compression is performed completely in frequency domain! The reason is that our knowledge of psychoacoustics is far stronger in that domain than time. So it reasons that changes that occur in frequency domain would be visible in frequency graphs just the same.

That said, in the case of pre-echo, the distortion is much more visible in time domain. So there is a partial point there but the general assertion is completely wrong that FFT is not revealing of differences.

Even more important here is that we can mathematically show that pre-echo occurs. That is, the objective proof is solid and without doubt at the most fundamental way. There is no such proof that cleaning up USB signal for example changes the analog output of a DAC. That is a leap of faith and there is no math or any kind of objective proof that works in every case as we have in pre-echo.

Here is the most damning point against this argument. Listeners are completely blind to many lossy compression artifacts. Take even that pre-echo. As obvious as that is, when you ratchet up the bit rate to 320 kbps, 99.999% of listeners fail to hear it and that includes audiophiles! In this case we have ditched 75% of our audio payload (1,400 kbps) and left only a quarter and folks are completely blind to what occurred. Now we are supposed to think that someone is able to sense the cleanliness of USB data pulses in their DAC output? I don't think so.

Now, we can cut through all of this and get to a simple point of agreement. In the case of above pre-echo demonstrations, we can perform the test blind and listeners will absolutely tell the difference between original and compressed. Show me that the same thing happens with UpTone ISO Regen and we are done!

Long time readers of my posts on this topic recall that I accepted a challenge to go to and perform such a test after Alex, the business owner of this company, said he would be able to pass it. But he backed out. My offer still stands.

So until then, let's pay attention to data in front of us. It is not created with any agenda or by ignorance. I understand every argument the designers make and I am here to say that it is the job of any high performance DAC to not need this device! I like to meet the designer of any high-end DAC and hear him say why he couldn't afford or didn't know about this type of signal cleaning inside his DAC. I am confident there are no such designers willing to do this.

 

[amirm]

Mmerrill says this in another page of that thread: https://www.computeraudiophile.com/...gain-looks-for-the-music-in-the-noise/?page=2

"Glitches occur due to the current draw changing when the DAC is going from handling all 0s to all 1s - the current draw suddenly jumps, causing noise to appear on the DAC's output."

Glitches? I am not aware of people complaining about glitches in high-performance or even cheap DACs.

Assuming what is meant is loss of performance, dealing with mixed-signal circuits is the #1 job of any DAC designer. That is what they get paid to do: to create sufficiently robust and isolated power supplies and digital circuits as to keep the sensitive DAC analog output from getting polluted.

My audio precision analyzer is one such device. It has a ton of digital circuits and sensitive analog. Yet it has no problem keeping those interactions apart.

Yes, you can be incompetent as I have shown with Schiit Modi 2 DAC (or careless). But when talking about high-performance DACs? No way.

And at any rate, those transition pulses easily show up in noise measurements. We are talking FFT analysis with noise floors of -130 dbFS! You breath the on the DAC and it will show up.

And here is the larger issue: all of these arguments are hypothesis. They can be proven with instrumentation. You can probe the DAC and show those "glitches." That is not done of course. It is easier to invent problems and then jump to solutions than trying to first verify one's knowledge and theories.

 

[amirm]

Then there is this :"As I said the issue is that people look at an FFT as showing the full information about a signal. I don;t know what you don't understand about this? Does Amir & those who read him not think that ISO Regen is doing zilch based on his FFT?

Whatever excuse you make about where the fault lies - the result is the same - these FFTs are over-valued

Do you think that Amir's FFT shows that the iso regen does nothing?"

Answering the last part, no it is doing stuff. Question is whether what it is doing is below level of hearing and even below level of far more sensitive instrumentation.

Let's first review what the "problem" may be to fix with such a device. We feed a DAC with USB. That requires a bunch of digital logic/microprocessor to extract and format the data in the way that that DAC chip (silicon) needs it.

The DAC itself needs multiple ingredients to produce corresponding to those audio samples: http://audiosciencereview.com/forum/index.php?threads/a-deep-dive-into-hdmi-audio-performance.56/

Assuming error free PCM audio samples, and ideal DAC, then the variables become reference voltage and clock.

Noise travelling over power supply lines from digital to analog circuits and even over air can contaminate those references and with it, directly change the analog output of the DAC.

In that article I referenced, I showed how HDMI input shows worse performance than S/PDIF using identical digital input samples. Here is an example:

We see much higher distortion levels with HDMI. Simple reason for that is the the implementation of HDMI requires video and lighting up all of those circuits and not paying attention to good implementation caused much degraded performance.

Here is the key point: the J-test signal and FFT easily dug out noise pollution caused by noise bleeding from digital to analog output of the DAC!

Reason is simple: change of reference voltage or clock stability cause modulation of our analog signal and that shows up as sideband peaks or widening of a "skirt" around the main tone if it is random noise.

Look at the measurements of any two DACs in stereophile and you will find that J-test results shows differentiation. We are not stupid here. We use this test because it can be shown mathematically and empirically to be highly sensitive to what may go on in the DAC.

Let's look at the HDMI vs S/PDIF again, this time in the case of ancient and obsolete Mark Levinson 502 processor:

The red is HDMI and the teal color one is with Berkeley Alpha USB adapter driving its S/PDIF input.

Notice how superb HDMI performance is where the noise and distortion components are all well below -120 db or so.

This shows what I have been saying about high-performance DACs. That even in the challenging case of HDMI, good designers know what they are doing and can deal with it.

Let's swap out the Berkeley for Audiophilleo USB to S/PDIF converter:

Notice the radically changed profile. Our testing is absolutely and superbly sensitive to changes in upstream digital implementations.

So the notion that we are using the wrong test and it doesn't reveal what happens upstream in digital circuits is non sequitur.

That devices like ISO Regen show no difference at all, even when I dig way deeper than the above measurements, means that they are not impacting the output of the DAC. They simply are not.

So the argument has no merit. The reason we don't see changes in the output is because cleaning a window 100 times is the same as cleaning it twice. The DACs that show no change are doing what they are supposed to do: isolation themselves from vagaries of USB.

 

[Jinjuku]

Jujinku, galvanic isolation can indeed be necessary but it depends on a number of factors as to whether it is an issue in any particular installation. You can get ground noise currents circulating. Some dacs are isolated so won't benefit from the device.

I didn't say it wasn't of value. You misread my first statement by the way. I'm talking about down stream isolation because the DAC may already have it inbuilt. My point was the point you made:

"Some dacs are isolated so won't benefit from the device."

 

[Sal1950]

For a device that seems to do nothing ... 4 pages! Perhaps we need to discuss about how to make our system better. A primer on multiple subs or ...anything more constructive would be welcome.

Where's the fun in that? LOL

 

[Sal1950]

That simply reminds me never to engage you on any subject. You always end up with nothing useful to contribute. It does always come out the same.

D, I put him on ignore long ago, his intellectual and verbal vomit is without value and may even cause brain damage with extreme exposure.
Engage at your own risk. LOL

 

[March Audio]

The manufacturers of the GI chips specify the jitter right in their data sheets. This jitter is only a secret to folks looking for it from the analog outs.

Sorry but that doesn't necessarily translate to the dac output.

Jitter in the usb data stream does not equate to jitter in the dac output.

If it's not visible in the dac analogue output it's not an issue.

 

[firedog]

Your ill thought out debate points are what are getting you into trouble:

1. Your straw man argument about galvanic isolation: It's evidently not needed on a competent DAC as Amir showed that the on/off switch doing nothing for properly designed DAC's
2. Behringer 204HD, Mytek Brooklyn, iFi. Emotiva says none of their DAC's need it. Chord says none of their DAC's. Benchmark says none of their DAC's So we are effectively into 'the dozens'

Why don't you mention all dozens or hundreds of DAC's that have their output improved by galvanic isolation?

Again, non-sequitur answer. Lots of companies say lots of things about their products. Doesn't make their claims true. Benchmark has made claims about earlier DAC models having unimprovable features/performance, and then brought out subsequent models that claim to improve the performance of the earlier perfectly performing device in those same areas. Happens with other companies, too. You're confusing marketing speak with facts.

There have been a small handful of DACs measured here. Doesn't prove anything about the rest of the DACs on the market and whether they might benefit from galvanic isolation or not. And by the way, the need for galvanic isolation could have nothing to do with a specific DAC model, but with it's environment. The same DAC might benefit from it in one setup and not in another setup. The maker of the DAC doesn't have anyway of knowing this in advance as a certainty.

Also really funny that you mention iFi to "prove" your point, as they market devices exactly parallel to the Regen and IsoRegen and make the same claims for them. They also market devices to galvanically isolate usb for your computer to DAC connection. One is called the "iGalvanic". Here's what iFi say about it:

Who benefits from the iGalvanic3.0?

Everyone who uses USB for computer audio. More specifically, the iGalvanic3.0 is the ideal solution to:

• Break ground loops
• Avoid noise-coupling in applications that require hi-speed USB transfers.

Thus, the iGalvanic3.0 is the perfect solution for computer audiophiles through to recording studios seeking maximum sound quality from their USB digital audio system.

I guess that is iFi saying none of their DACs need it....

Try again. Maybe you can come up with a good argument. So far, you are definitely scoring lots of debate points with yourself. Invective and half baked examples are not what I would call "intellectual honesty".

BTW, since in another post you wrote that you know that I'm trying to defend a position that I know is incorrect, please tell me what position I'm trying to defend.
I don't actually think I've taken a position here. Just trying to understand all sides of the argument. As far as I can understand, there are knowledgeable people on both sides of the "USB cleaner device" argument who seemingly make good points for their side.
I've tried several of these devices in a couple of different setups and have sometimes thought they made a small positive difference and sometimes not.
My present setup has galvanic isolation on the USB input and I don't hear a significant improvement using these devices.
I also am totally open to the possibility that everything I think I hear in these scenarios is due to some kind of confirmation bias.

 

[amirm]

There have been a small handful of DACs measured here. Doesn't prove anything about the rest of the DACs on the market and whether they might benefit from galvanic isolation or not.

Which DAC do you have that you say shows *any* improvement with it and are you willing to loan it to me for measurement?

For now, I have tested some of the cheapest DACs on the market, going down as low as $70. What are the odds that much higher end ones need help and these don't?

 

[firedog]

Which DAC do you have that you say works with it and are you willing to loan it to me for measurement?

For now, I have tested some of the cheapest DACs on the market, going down as low as $70. What are the odds that much higher end ones need help and these don't?

Not sure I understand your question. I used a couple of these USB cleanup devices with a Mytek 192 DSD DAC, as an example. and thought they made a positive contribution. I thought the FW input on the Mytek sounded better than the USB input until I added one of these USB clean up devices. After that I thought the USB was equal to the FW in SQ.

My present setup has galvanic isolation on the input and I don't hear a clear difference with them in line. My present setup is a Kii Three system and the input is on the Kii Control. It's fairly new and I'm still experimenting with it, so I might change my mind about that in the future.

Can't send you my device for two reasons: a) my setup totally won't work as I need it to without the Kii Control; b) I'm not in the US, so the time, cost, and hassle are prohibitive.

Historically, USB inputs of DACs, even some relatively expensive ones, haven't been the area most DAC makers put their greatest efforts into. Some manufacturers were even sort of anti-USB and said so. Obviously in the last few years that has changed for many DAC makers.

I don't think there is a strict correlation between the cost of the DAC and the quality of the USB input. I've seen some not inexpensive devices where the USB seemed to be something of an afterthought, just added on for marketing reasons, and not because the manufacturer was very interested in USB.
We can also see that DAC manufacturers often drop one USB interface and go for a one from a different source in a newer model. One of the reasons for this is probably that they decide the USB input on the older model was inferior.

 

[Jinjuku]

Again, non-sequitur answer. Lots of companies say lots of things about their products. Doesn't make their claims true. Benchmark has made claims about earlier DAC models having unimprovable features/performance, and then brought out subsequent models that claim to improve the performance of the earlier perfectly performing device in those same areas. Happens with other companies, too. You're confusing marketing speak with facts.

I'm not confusing anything. I'm seeing a Schit Modi 2 have it's poor output improved with a regeneration device. I'm seeing a $79 Behringer do what the Modi 2 does after throwing another $325 at it.

Have you seen the AP analyzer results?

There have been a small handful of DACs measured here. Doesn't prove anything about the rest of the DACs on the market and whether they might benefit from galvanic isolation or not.

It proves there are DAC's at $79, ~$350, $2000 price points that keep the output free from what is going on in the computer.

Also really funny that you mention iFi to "prove" your point, as they market devices exactly parallel to the Regen and IsoRegen and make the same claims for them. They also market devices to galvanically isolate usb for your computer to DAC connection. One is called the "iGalvanic".

Good. If they produce a DAC that needs an additional gadget to correct their engineering deficit I'll not recommend them either.

 

[Jinjuku]

What are the odds that much higher end ones need help and these don't?

Fire Dog may not understand the premise of 'sampling'.