Amir at ASR claims Uptone won't sell the ISO regen to him...

[PeterSt]

5 minutes ago, mansr said:

What exactly do you suggest is missing?

 

The way we use USB Audio is not so much error corrective, like the normal usage. So a hdd connection is allowed some error rate (though don't ask me where and how this is written out) because it will be corrected.

Well, really no need to elaborate further.

[PeterSt]

20 minutes ago, mmerrill99 said:

Are you saying that USB audio has bit errors?

 

Shouldn't but can have. Nothing prevents from it.

And users of a device which I won't name now are just accepting them. Not that they realize. 

[mansr]

1 minute ago, PeterSt said:

The way we use USB Audio is not so much error corrective, like the normal usage. So a hdd connection is allowed some error rate (though don't ask me where and how this is written out) because it will be corrected.

Well, really no need to elaborate further.

Yes, as stated in the spec, USB audio uses isochronous transfers with error detection but without retransmission on error. Why do you insist there is no spec?

[PeterSt]

13 minutes ago, mansr said:

In my testing, I had to try pretty hard to provoke bit errors over USB.

 

How did you know you had USB errors ?

[PeterSt]

4 minutes ago, mansr said:

Why do you insist there is no spec?

 

You have trouble reading Dutch now.

Have fun with your error detection without correction. OK ?

And tell the manufacturers.

[Speed Racer]

3 hours ago, pkane2001 said:

Assuming no bits are flipped in transmission, the only effect an improved, regenerated digital signal can have on the analog output is to affect timing errors. I.e., reduce or increase jitter.

 

You are looking at too narrow of a picture. If all you consider is the digital signal itself, there would be zero reason to to buy any type of decrapifier. You have to consider the effect ground loops, AC leakage, etc., have on the receiver USB PHY. In other words, you need to consider all aspects of what the ISO Regen does and how it might affect the music to judge its effectiveness. Not just jitter....

[PeterSt]

38 minutes ago, Jud said:

 

[pkane2001]

Just now, Speed Racer said:

 

You are looking at too narrow of a picture. If all you consider is the digital signal itself, there would be zero reason to to buy any type of decrapifier. You have to consider the effect ground loops, AC leakage, etc., have on the receiver USB PHY. In other words, you need to consider all aspects of what the ISO Regen does and how it might affect the music to judge its effectiveness. Not just jitter....

 

OK, I considered them... And yet, all these effects get corrected on the digital side before entering the DAC with ISO REGEN.

 

How does anything a digital decrapifier do in the digital domain translate into an improvement in analog signal? A friend used to make optical USB isolators and sell them for $25 about 10 years ago. I suspect that this will break up current leaks and ground loops just as effectively. So, what else does ISO REGEN do that a $25 piece of kit doesn't? Reduce jitter, perhaps?

[mansr]

8 minutes ago, PeterSt said:

How did you know you had USB errors ?

I captured the digital output of a USB to S/PDIF interface. With a proper USB cable, there were no errors. With a tangled mess of wires in place of a cable, errors started showing up.

[PeterSt]

20 minutes ago, PeterSt said:

 

[rickca]

3 minutes ago, PeterSt said:

Can't we change the subject to MQA or so ?

Then you have to deal with the MQA thought police.

[Sal1950]

49 minutes ago, Jud said:

 

Alex sent me and @lmitche each two identical looking ISO Regens, asking us simply to listen and separately let him know what we thought.  The only difference between the two was a strip of blue painter's tape on the top of each, where in black magic marker the letter "G" was written on top of one, and the letter "M" was written on top of the other.

 

I plugged each ISO Regen into my system in place of the original Regen.  I only had to listen to each once to know that I very much preferred "G."  The whole thing took maybe five minutes because the difference was so apparent.  (I liked both G and M better than the original, but of course that comparison was non-blinded.)

 

Afterward I learned @lmitche's experience was pretty much a carbon copy of mine.

Well there ya go.  You should present that as a paper to the AES.  LOL

[Jud]

1 minute ago, Sal1950 said:

Well there ya go.  You should present that as a paper to the AES.  LOL

 

Nope, I'll just happily listen to my rig with an item in it that I blind tested a prototype of, and it passed with flying colors, same as with the other tester.  Anything in your system that you personally and another person independently have blind tested?

[Jud]

23 minutes ago, pkane2001 said:

 

OK, I considered them... And yet, all these effects get corrected on the digital side before entering the DAC with ISO REGEN.

 

How does anything a digital decrapifier do in the digital domain translate into an improvement in analog signal? A friend used to make optical USB isolators and sell them for $25 about 10 years ago. I suspect that this will break up current leaks and ground loops just as effectively. So, what else does ISO REGEN do that a $25 piece of kit doesn't? Reduce jitter, perhaps?

 

At least as I understand what John has explained about the theory of operation, there are two aspects to it.

 

First, as with the original Regen, a cleaner signal allows the USB PHY receiver chip in the DAC to work less hard, creating less self-noise in the DAC circuitry.

 

Second, the isolation prevents both ground and leakage currents from utilizing the DAC circuitry as part of their pathways.

 

Both of these should help keep noise out of sensitive clock circuitry in the DAC, and the isolation should help to avoid some ground and leakage loops that might create noise in the overall system.

 

One comparison to the optical isolators you are familiar with is that although they provide isolation, they can have relatively high levels of self-noise and may therefore not be the best choice to use in DAC circuitry.

[mmerrill99]

8 minutes ago, Jud said:

One comparison to the optical isolators you are familiar with is that although they provide isolation, they can have relatively high levels of self-noise and may therefore not be the best choice to use in DAC circuitry.

All isolators introduce jitter, some more than others. Optical isolators also do not work at high speed USB 2, which is what most USB audio now utilises

[Jud]

1 hour ago, Ralf11 said:

 

No.  I looked for it and did not find it.  Neither did another person.

 

What makes you think the above, and do you have any connection with the business or principals?

 

They still do not have the guarantee on any other product pages (as of last night).

 

I have no axe to grind in this fight and do not use a USB connection.

 

Then you will want to take along with you the next time you buy lottery tickets the customer in the ISO Regen launch thread who on April 26th of this year noted the 30 day risk free trial for it, since he apparently foresaw it on the website more than a month in advance of when you say it appeared.

[PeterSt]

 

47 minutes ago, mansr said:

I captured the digital output of a USB to S/PDIF interface. With a proper USB cable, there were no errors. With a tangled mess of wires in place of a cable, errors started showing up.

 

Of course. But my Dutch was this :

 

1 hour ago, PeterSt said:

How did you know you had USB errors ?

 

 

[pkane2001]

9 minutes ago, mmerrill99 said:

All isolators introduce jitter, some more than others. Optical isolators also do not work at high speed USB 2, which is what most USB audio now utilises

 

Great. So, the effect of ISO REGEN is then to do what... reduce jitter compared to an optical isolator?

[mmerrill99]

19 minutes ago, pkane2001 said:

 

Great. So, the effect of ISO REGEN is then to do what... reduce jitter compared to an optical isolator?

You don't seem to understand that your $25 optical isolator cannot isolate at this 480Mbps speed so your claim "it will break up current leaks and ground loops just as effectively" & asking what the ISO Regen does is silly - the ISO Regen does actually " break up current leaks and ground loops" at the USB speeds now used in audio, unlike your optical isolator

[Jud]

23 minutes ago, pkane2001 said:

 

Great. So, the effect of ISO REGEN is then to do what... reduce jitter compared to an optical isolator?

 

Hi Paul -

 

I would guess it's not impossible to do the degree of noise reduction in the DAC itself as is done with the ISO Regen - one could essentially have an ISO Regen inside the DAC, or in other ways reduce aspects of self-noise and ground and leakage currents.  (Though recall one reason BADA said it kept its USB/SPDIF converter separate from the DAC was for noise reduction purposes - perhaps avoiding radiated EMI [I don't know, just blathering here]?)  But I think you'd agree the concept of keeping noise out of the DAC clock is solid.  And my impression at least from what I've read is that John seems to have had a pretty good handle on component selection and circuit and board design to accomplish that intended goal.  

 

We're then left with the topic of whether any reduction in noise accomplished by the ISO Regen will be audibly evident in the analog product.  The blind testing is for me a fairly strong indication *some* change is making it through to the analog side.  I can always be flat wrong, but the amount of readily identifiable difference between the two units with no expectation bias operating, plus the identical results from the other tester, does leave an impression even from these anecdotal results.

 

Of course we then run into the issue of figuring out whether the change (crediting for the moment the notion that I'm correct about the existence of a change) and the mechanism causing it are as John intended.  For that we may have to wait awhile.

 

[pkane2001]

39 minutes ago, mmerrill99 said:

You don't seem to understand that your $25 optical isolator cannot isolate at this 480Mbps speed so your claim "it will break up current leaks and ground loops just as effectively" & asking what the ISO Regen does is silly - the ISO Regen does actually " break up current leaks and ground loops" at the USB speeds now used in audio, unlike your optical isolator

 

Please explain how an optical isolator will not stop ground loops or leakage currents.. By the way, current audio standards require well under 100Mbps bandwidth.

[mmerrill99]

23 minutes ago, pkane2001 said:

 

Please explain how an optical isolator will not stop ground loops or leakage currents.. By the way, current audio standards require well under 100Mbps bandwidth.

If a channel can't pass the USB signal, your question is nonsensical - your optical isolator can block everything including the 480Mbps signal so dead silence is guaranteed

 

No matter how much you protest, current USB audio uses 480Mbps as it's de facto standard

[mansr]

4 minutes ago, pkane2001 said:

Please explain how an optical isolator will not stop ground loops or leakage currents.. By the way, current audio standards require well under 100Mbps bandwidth.

USB wire speed is 1.5 Mbps (low speed), 12 Mbps (full speed), or 480 Mbps (high speed). If 12 is insufficient, you must step up to 480. That said, optical technology capable of far higher speeds is readily available (Ethernet). I don't know what USB products exist, if any, but that doesn't mean there are none.

[MikeyFresh]

4 hours ago, mansr said:

Those people all sell their own various magic potions intended to remedy this supposed problem. I won't go so far as to call them liars, but they have more than a little motive to exaggerate the severity of the issue. It is trivially true that band-limiting a signal involves some amount of "smearing" in time if the input has high-frequency content that gets removed. Low-pass filtering and smearing are synonymous, insofar smearing can be considered a technical term at all.

 

 

Sure sure, "those people" sell "magic potions intended to remedy this supposed problem".

 

Have you posted your beloved detailed measurements refuting the efficacy of these magic potions, or debunking the very existence of any supposed problem yet?

 

You won't call them liars, except that effectively you just did, and you are taking shots at a pretty well respected group there, no?

 

Why would you take such a direct shot at the integrity and ethics of that group?

 

Full disclosure: I own/use nothing at all offered by the folks you snipe at.

 

You are clearly very intelligent, but posts like the above begin to call everything into question. Why would you do that to your self?

 

I don't know who you are nor do I care, but you can't be in any position to make such proclamations. Who died and left you head of the audio consumer protection police unit?

 

 

 

 

[pkane2001]

15 minutes ago, mmerrill99 said:

If a channel can't pass the USB signal, your question is nonsensical - an optical isolator can block everything including the 480Mbps signal so dead silence is guaranteed

 

No matter how much you protest, current USB audio uses 480Mbps as it's de facto standard

 

The only reason ground loops and leakage currents are a problem in a conventional circuit is that they are traveling along pathways that were not designed to filter them out. In an optical isolator, it is trivial to filter out all noise and leave the data signal since they both come through the same input.

 

Regardless of USB speed, the actual audio data rate is a lot less than 480Mbs. Isochronous transfer protocol allows the endpoint to decide what portion of the overall bandwidth will be used for the transfer. None of the commonly used audio protocols/formats approach anything close to 480Mbs.