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

[Jud]

3 hours ago, plissken said:

 

Uh, his ears. As in Alex should allow for someone to setup a blind testing rig.

 

Get a windows machine and two DAC's. Feed the DAC's output into a preamp with multiple inputs. One DAC has the regen and another not. Windows can feed both DAC's the same stream at the same time.

 

This would be single blind with someone doing the input switching. 

 

I was one of two people to do blind testing on preliminary test versions of the ISO Regen.  The other tester and I each independently selected the same test version (the one closest to the current production build) within 5 minutes of listening.  Not close between the two.

 

So what you're asking for already happened.

[Jud]

12 hours ago, esldude said:

Sorry, you can't listen to that signal.  People can only listen to the analog output of a DAC.  Do you have any measurements that show any improvement in the analog output of a DAC with the Regen vs without?

 

Due to the large difference in sound between the two test units found by me and the other blind tester, I think there is some difference occurring at the analog output.  Whether this difference (which both the other tester and I heard as a substantial positive one) is in fact in the direction of greater accuracy and occurs in the way John Swenson, the designer, believes it does, may have to wait until John is able to set up the tests he wants to do.  Or perhaps someone else will be able to trace effects all the way through from digital output of the ISO Regen to analog output of the DAC.

[Jud]

1 hour ago, wgscott said:

What would be of great benefit would be to depersonalize this issue.

 

If folks could agree to do that, then the next step would be to determine what measurement or set of measurements both "sides" of the debate could agree in advance would be decisive either way.

 

The third step would be to find some competent, neutral party that has access to the equipment, to cary out the experiments.

 

We've already had independent blind testing by two people (I was one) in which the test design most closely resembling the production version of the ISO Regen was decisively chosen in a few minutes of listening.

 

If we don't get analog DAC output measurements (or for that matter digital input measurements) to explain this, then where are we?  Should we conclude the two blind testers confidently deluded themselves so strongly in the same direction (the same direction as two non-blinded listeners, including the designer)?  Or in that case would we credit the blind test results over the lack of confirming measurements and say maybe the thing works, but we're not sure how?

[Jud]

18 minutes ago, jabbr said:

 

So, assuming this is valid with a larger number of evaluators, a proper measurement would be able to distinguish something that is audible. eg if there are phase error differences that would lend support to the proposition that altering phase error is audible.

 

That's what the ideal state would be - if measurements such as you and John have proposed (or that @PeterStmay have already done or be contemplating) would turn out to correspond to the blind test preference.

[Jud]

1 hour ago, Ralf11 said:

 

I am glad you added that to your web site.

 

 

 

If by "adding" you mean "posted prominently on the product page ever since the page first appeared," then you are correct.

[Jud]

8 minutes ago, sdolezalek said:

One of the things I find quite amusing about this whole thread is that, if my memory serves me correctly, a lot of the folks who are taking the "there is no difference unless I can measure it -- science is absolute" stance here are the same ones who have expressed strong dopubts about Climate Change in prior posts on CA.  I guess "opinions" are ok in other areas of science, but audio is such a settled science that there can't possibly be an improvement we can't readily measure...

 

I am not certain your memory serves you correctly.  On the other hand, it's quite possible I'm the one with the faulty memory.

[Jud]

Just now, sdolezalek said:

stepped up here to say that you clearly hear a difference that the "measurement" addicts seem to suggest cannot exist.

 

Importantly, I clearly heard it in a blind test.

 

Several folks pushing for measurements in this thread have, in other threads involving measured differences, said the real acid test would be the ability to tell a difference in a blind test.  Here we have that.

 

I understand (and have already noted I agree) that the ideal situation is valid listening tests and measurements confirming each other, since that gives us a path toward real reproducible improvement.

[Jud]

8 hours ago, lucretius said:

 

Hmmm .... this is almost suggesting that the designers accidentally created a product which works. I would rather believe they deliberately created a product which works by building it to meet some criteria. Is it wrong to ask what those criteria were?

 

Hmm nothing.

 

My statement was preceded by and predicated on "In that case," meaning in the case where we were not successful in obtaining measurements.  So first, it is looking toward a future possibility, not assessing current facts.

 

The designer, a highly qualified and experienced engineer, has a theory of operation of the circuit.  (I.e., this is not a "shot in the dark.") Two blind tests selected the version of the circuit that ought to've worked better to accomplish the design intent.  At this point the question is whether or not measurements will become available to confirm the circuit works as designed.

 

 If we aren't able to get the measurements (not a trivial thing), then what do we think?  Maybe it works, though we haven't been able to confirm how?  Or we ignore the "chops" of the designer and the blind test results and say we won't concede even the possibility it may?

[Jud]

6 minutes ago, mansr said:

No disrespect intended, but what you have provided amounts to nothing more than an anecdote. We don't know the difference between the devices you tested, and your setup wasn't documented. This means nobody can accurately repeat it or even assess how well you accounted for incidental variables that might have affected the outcome. The number of participants was also far too small to say anything with confidence. I realise you didn't set out to perform a scientifically rigorous test, so please try not to pass it off as one.

 

Certainly it wasn't a scientific test.

 

Now will everyone who doesn't have scientifically conducted blind tests verifying a piece of their audio systems functions as claimed, and who does not completely understand the circuitry and function of that piece of equipment on an engineering level with verifying measurements, please get rid of that unscientific piece of no-good junk.

 

Once we've cleaned out our audio systems, we can start on our computers, cars, and homes.

[Jud]

11 hours ago, pkane2001 said:

 

What baffles me to no end is how so many folks get convinced that measurement couldn't possibly be useful in predicting audio performance. I'm sure that some snake oil peddlers would like you to believe that. But objective, repeatable measurement is key to testing the performance of any electronic device. This is overwhelmingly the practice of all competent electronics engineers and designers.... except, it seems, in hi-end audio.

 

If the device 'cannot be measured' or 'the measurements don't demonstrate what it does' then how do you know that it does anything positive to the signal? To me, this is a warning sign that the manufacturer or the designer don't know what they are doing or trying to hide something. Especially if they tell me that I wouldn't understand even if they tried to explain it. Try me: I'm not that dense.

 

Being able to pick the device out in a blind test is a good start, but that only proves there is a difference. Whether the difference is for the better or worse will often depend on the preferences of the listener.

 

My approach is to research a device before I buy it. I want to understand what it does, how it does it, and whether there is some objective proof (in the form of measurements) that the device achieves these goals. Obviously, I also would like to hear that others found that the device works, producing the advertised effect. Does this make me a "measurement addict"? So be it.

 

I find no problem with anything you said there.  In fact I share them (and have said in this thread that would be the ideal situation).  To a greater extent than you, at least in the audio area, I have to work from an imperfect understanding.

[Jud]

54 minutes ago, mansr said:

Nice straw man. I've never suggested that everybody must understand and personally validate the design of everything they use. It is quite sufficient that somebody does this. The problem with many audiophile widgets is that nobody has done anything to validate their operation. In some cases, the manufacturer even actively prevents others from testing it. Would you buy a car from a manufacturer who refused to let it undergo standard testing? What of a car manufacturer who was found to be rigging tests in its favour? Do they get a free pass, or are they hauled in front of court?

 

Let's use your "somebody does this" criterion.  Apologies to Bill and Dennis: since I know at least a little bit about your systems, at least as they existed at some point not too long ago, I want to use them, along with mine, as examples.

 

I believe both Bill and Dennis use digital room correction/equalization.  There is substantial academic literature regarding human insensitivity to the overall system frequency response this is designed to optimize.  Nearly all these systems use minimum or intermediate phase filters.  Is the favorable response to these systems due to overall frequency response optimization, or to a slight euphonic "reverb effect" in the audible range from the post-ringing of these filters?  I'm unaware of academic/scientific studies proving one or the other.  Why Bill and Dennis, you cock-eyed subjectivists!

 

Dennis at one time owned Spectral Audio equipment, as I do now (one bought new in 1993, the other of mid-90s vintage bought used).  Something Dennis has mentioned in the past is that the parts and circuit designs of Spectral amps are supposed to minimize "thermal tails."  (This is mentioned in information on the Spectral website.)  I don't know about Dennis, but for my part I'm not aware of scientifically conducted blind testing to assess the effect of avoiding "thermal tails" vs. possibly less costly parts and designs that might be subject to them to some minimal extent.

 

So, to put it concisely, we operate on partial information.  And within that partially informed context, we choose what to trust and what to be skeptical of.

[Jud]

12 minutes ago, mansr said:

it can't hurt to have a more correct response.

 

Are you quite certain, through scientific testing you or someone else has conducted, that it is a more correct response via-a-vis any possible reverb effect in the mid and upper portion of the frequency band?

[Jud]

5 minutes ago, mansr said:

I'm quite certain that removing, say, a 5 dB hump at 100 Hz is better than not doing this.

 

Better than not doing it if you factor in potentially adding euphonic reverb in the mid and upper frequencies?

 

You said the difference in bass was "clearly audible" to you.  Did you test this blind so as to remove any expectation bias, or even better, research the academic literature to confirm scientifically the favorable effects you thought were clearly audible?

[Jud]

17 minutes ago, mansr said:

No, I haven't done rigorous testing. However, I'm not the one selling it, so that burden isn't on me. I also have no reason to suspect them of secretly adding reverb rather than doing what they say they're doing.

 

I am not selling the ISO Regen.  I did, however, participate in a blind test of two candidate designs, where I very quickly selected the one most like the current production model because of what I felt were clearly audible differences.  The other blind test participant did the same.

 

Of course with regard to minimum phase and intermediate phase filters, there's no "secretly added" reverb.  Rather there is the potential for reverb if post-ringing has that audible effect, something various people have said is so, but that hasn't at least to my knowledge been established in the scientific literature one way or the other.

[Jud]

17 minutes ago, mansr said:

Filter ringing occurs at inaudible frequencies. Reverb is something else entirely.

 

I've read several people quite familiar with digital filtering (as I recognize you are yourself), including Miska, Peter, and whoever did the filter design work for Ayre and Charles Hansen, say that ringing, though ultrasonic, smears the audible signal over a greater period of elapsed time, creating an audible effect similar to reverb.

 

Another effect of intermediate and minimum phase filters is dispersion, spreading out the signal in time in accordance with frequency.  This occurs at audible frequencies.  The people responsible for the design of the ESS DAC chip have written that this can provide an increased sense of depth.  However, I haven't seen perception of this depth effect confirmed in the scientific literature either.

[Jud]

25 minutes ago, plissken said:

 

You might as well blind audition two minidsp with different x-over slopes and topologies for that matter..

 

Crossover slopes weren't being tested.  Circuit components were. Would you like to know which of two pieces of equipment performing the same function but  built with different parts sounded better (or if there was no difference)?

[Jud]

16 minutes ago, Sal1950 said:

I've heard you refer to various successful blind tests involving the Reg but never found any actual details, sorry if I missed them. Would you be so kind to point me to their posting or supply some further info here.

Exactly how was this test conducted? Who were the participants?  What were the various components involved, source, DAC, etc? What source material was used? How many rounds of tests were made?  What were the specific "blind" conditions. What were the final voting numbers.

TIA

 

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.

[Jud]

4 minutes ago, mansr said:

In my testing, I had to try pretty hard to provoke bit errors over USB. When they did occur, it was blatantly obvious.

 

Yes, I don't think anyone is talking about "flipping bits" or actual dropouts as events that wouldn't be pretty obvious.

[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.

[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.

[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.

 

[Jud]

3 minutes ago, plissken said:

You were comparing items that most likely have very measureable differences in output

 

You mean two versions of the ISO Regen that everyone has been going on for pages here wondering how to measure any differences from?

 

What exactly do you expect would be so wildly out of spec between two versions of USB-hub-with-isolator-chip, and what measurements or examination of the circuit topology are you basing these strange accusations on?  You talked about 120V - are you seriously thinking a USB hub will be sending that or anything else similarly far out of spec to a DAC, and that the DAC would still be playing music if it did?  Or that differences in *sound quality* would result from a comparison between two hubs that were so severely compromised?

 

Talk about needing new physics to explain some people's weird ideas....

[Jud]

12 minutes ago, mansr said:

I was fooling around with an old Cambridge Audio AVR recently. As it turned out, feeding it an unexpected, but in-spec, S/PDIF signal made it emit smoke.

 

Yes, that's just what happened with my DAC - black smoke with one hub, white smoke with the other, so of course I knew which one to choose as Regent, er, Regen.

[Jud]

6 hours ago, Ralf11 said:

 

An imaginary customer?

 

You are certainly a vociferous advocate for this co. - do you have any sort of relation with them?

 

An "imaginary customer" who posted in threads here in April? Flail much?

 

As for my relationship, first, I consider myself a friend of Alex and John's.  This has given me the mighty mental power to conjure up an imaginary customer to post in the forum here about the 30-day satisfaction guarantee back in April, more than a month before it magically appeared to you.

 

Second, as I've posted prominently in each of two forum comments where I've talked about my listening experience with the current production model, in return for testing Alex provided me a production model for free.  I did that so anyone considering purchasing one could evaluate my comments knowing this.

 

By the way, I believe what "the other person" said was that he couldn't find it in Google or in the site footer, if I understand him correctly.  If I do, it would leave you as the only one claiming to have read that full product page and not found it.