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

[jacquesr]

3 hours ago, cpvniii said:

Superdad: Few have ever cranked up a going concern from nothing and grown it over a number of years, iterations, new product development and roll out, managing cash flow, distribution, taxes etc. I have used your product and I like it. I can here the difference. I own 4 Dacs and all of them sound better "to me".But my real point here is a rather simple but an oft overlooked one.

The real power in any business is to be at a point where you can choose who you will do business with.

Congratulations. You are there. I wouldn't do business with anyone who wished me and my company harm.

It doesn't matter who is right and who is wrong. That is 3rd grade stuff. What truly matters in life is what is right....and what is wrong. And furthermore, just because someone has the right to be an ass doesn't mean it is the right thing to do. Carry on.

Being a business owner myself, I totally agree with you. Some customers can destroy your business. Choose wisely. Avoid Dicks and some other first names too. PM me for a list. Who said CA could be so much fun.

[elcorso]

I honestly do not see the need to bring discussions from other forums to this one.

 

Nor to attack (or defend) one who is not present in this, Amir.

 

The only thing I can say about Amir is that he is more "objectivist" than Prof. Scott.

 

We are moving to "climate change". Beware, it is a much more controversial issue than whether ISO Regen works or not, and what measures of it serve us for something.

 

As for climate change, it is better to observe in glaciers what happened millennia ago. Recall that time is quantum, so 10 or 20 millennia does not make much difference. Meanwhile, China continues to consume millions of tons of coal, which maintains North Korea's economy. Even if they say they still agree with the Paris Protocol now.

 

Roch

[Ralf11]

45 minutes ago, pkane2001 said:

* * *

I want to understand

[1] what it does,

[2] how it does it, and

[3] whether there is some objective proof (in the form of measurements) that the device achieves these goals. 

[4] I also would like to hear that others found that the device works, producing the advertised effect. 

 

...

[JohnSwenson]

As Alex mentioned I will soon have test equipment to do accurate phase noise measurements of very low phase noise clock systems, and thus be able to actually measure DAC clocks in system while playing music.

 

The measurements of analog out from DACs is a much harder concept. Remeber we are trying to measure the difference on an analog waveform due to very small jitter differences. You can't just do this with a $200 ADC and an FFT. It takes a high resolution ADC with a clock system that has a jitter level significantly lower than what you are trying to measure. To get decent resolution in the output the FFT needs to be done over a very long time, over which the reference clock is not wandering, which will mess up the results.

 

The APs are not even close to being able to do this. I don't know of ANY existing test equipment that can do this.

 

The test @jabbr mentioned, playing a pure tone through the DAC and doing a spectrum and looking at changes in the "skirt" is probably a very good way to test this, but with existing test gear the skirt from the test equipment is going to be wider than what you are trying to see, again not a particularly useful test.

 

It seems to me that the most promising measurement system is to use a cross correlation phase noise system that has been designed to work at audio frequencies. This at least theoretically has the resolution to distinguish differences in the audio out due to jitter changes in a good DAC, but nobody has built one. That will have to be something else I look into building.

 

So "just sending it out to a third party to measure" is not going to be a particularly useful test, since nobody else has any test equipment that is going to be able to measure the effects that the ISO REGEN is designed to produce. Of course they can measure unrelated things like noise floor, but that is not the same as measuring jitter effects in the range we are addressing.

 

John S.

[lucretius]

4 hours ago, Jud said:

 

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?

 

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?

[esldude]

43 minutes ago, JohnSwenson said:

As Alex mentioned I will soon have test equipment to do accurate phase noise measurements of very low phase noise clock systems, and thus be able to actually measure DAC clocks in system while playing music.

 

The measurements of analog out from DACs is a much harder concept. Remeber we are trying to measure the difference on an analog waveform due to very small jitter differences. You can't just do this with a $200 ADC and an FFT. It takes a high resolution ADC with a clock system that has a jitter level significantly lower than what you are trying to measure. To get decent resolution in the output the FFT needs to be done over a very long time, over which the reference clock is not wandering, which will mess up the results.

 

The APs are not even close to being able to do this. I don't know of ANY existing test equipment that can do this.

 

The test @jabbr mentioned, playing a pure tone through the DAC and doing a spectrum and looking at changes in the "skirt" is probably a very good way to test this, but with existing test gear the skirt from the test equipment is going to be wider than what you are trying to see, again not a particularly useful test.

 

It seems to me that the most promising measurement system is to use a cross correlation phase noise system that has been designed to work at audio frequencies. This at least theoretically has the resolution to distinguish differences in the audio out due to jitter changes in a good DAC, but nobody has built one. That will have to be something else I look into building.

 

So "just sending it out to a third party to measure" is not going to be a particularly useful test, since nobody else has any test equipment that is going to be able to measure the effects that the ISO REGEN is designed to produce. Of course they can measure unrelated things like noise floor, but that is not the same as measuring jitter effects in the range we are addressing.

 

John S.

I do believe everything in your post is as stated.  To me that brings into question how audible such a thing as very low levels of jitter would be.  We really have very little reason to believe such jitter levels result in anything that can be heard other than people saying they hear it when they think it has changed or know the gear in use has changed.  Also the differences in the signal that are caused by such low levels of jitter are swamped by a myriad of other uncontrolled effects upon the signal.  Like ambient noise levels to name just one.

[sdolezalek]

2 hours ago, wgscott said:

 

Don't know if I am included in this, but if so, your memory couldn't have served you more incorrectly.

 

No professor, you are one of the ones that consistently seems to put science in the proper perspective.    That was why I included the caveat.  Doesn't mean you can't throw the cat among the pigeons once in a while, but seemingly just for fun. 

[sdolezalek]

2 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....objective, repeatable measurement is key to testing the performance of any electronic device. 

 

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? 

 

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.

 

I think the real questions are understanding what to measure, and what to hear in a blind test.  We can measure differences that have no audible impact on sound and we can hear differences in blind tests that don't show up in a measurement because we aren't measuring the right thing.  We can also hear clear differences and may choose the less accurate sound as preferable.  Similarly, without listening, it is really hard to tell which among a whole series of measurements is most important in identifying more accurate sound.  

 

I fully agree with your notion of research because it tends to at least identify both what measurements and what hearing opinions exist.

[wgscott]

2 hours ago, elcorso said:

I honestly do not see the need to bring discussions from other forums to this one.

 

Word.

[jabbr]

2 hours ago, JohnSwenson said:

The test @jabbr mentioned, playing a pure tone through the DAC and doing a spectrum and looking at changes in the "skirt" is probably a very good way to test this, but with existing test gear the skirt from the test equipment is going to be wider than what you are trying to see, again not a particularly useful test.

 

It seems to me that the most promising measurement system is to use a cross correlation phase noise system that has been designed to work at audio frequencies. This at least theoretically has the resolution to distinguish differences in the audio out due to jitter changes in a good DAC, but nobody has built one. That will have to be something else I look into building.

 

 

I have a few questions.

 

The suggestion I made of a measurement on the analog output of the DAC assumes the jitter would measurably widen the frequency band. This would be with a high resolution spectrum analyzer. What information leads you to state that existing spectrum analyzers do not have sufficient resolution? What resolution are to estimating would be needed?

 

In the second case you are measuring the phase error of the DAC clock. which isn't itself in the audio frequency range. Certainly frequency offsets in the audio frequency range are easily measurable.  The internal mixer of my system has a minimum frequency of 5 Mhz and so should be fine with most DACs. One can use an external mixer when lower frequencies are needed. (e.g. Rutgers' appoach)  In any case these measurements can be made with current equipment, and have because, well, DAC clocks have been measured. Are you looking at measuring something else?

 

Not that a digital approach wouldn't be great, just will postpone the measurements until some date after which the measurement system is developed.

[firedog]

7 hours ago, plissken said:

 

No, I'm pointing out that a online retailer is simply missing some site basics. I'm not pushing anything off. I tried the Schitt Wyrd because they list the returns policy for each product on the respective page. It didn't do anything for my Emotiva Stealth DC-1 so it went back. Same with the AQ Jitterbug. I'm thinking the DC-1 isn't powered by the USB bus and the C-Media in it can be externally powered. 

 

I wanted to try the Uptone Regen awhile ago but didn't see anything about what happens if it didn't do anything for me. Yes I could have called the manufacturer or just deal with an outfit that makes that conspicuous. 

 

Kudos to Alex/Uptone putting the 30 day MBG on their product page BTW. 

Okay, but I used to deal professionally with lots of SMB web site owners like Alex. Don't forget that these businesses are essentially one man shows, with possibly a very small number of employees who do very specific tasks like assembly. Usually the owner does all the "executive" functions, and in addition helps out with production, transport, shipping, etc. 

 

As odd as it may seem to you and others, having the perfect web site or 100% accurate and up to date web site is the last item in their list of priorities. 

 

Running the actual business and keeping actual customers supplied and happy takes up so much of their time that they rarely get around to web site upkeep. It's easy for outsiders to say that is a mistake, but I think most of these small business owners are very aware of what's most important to keep their business running and cash flow coming in. They correctly see web site maintenance, etc., as a secondary issue. In a perfect world it would be otherwise, but reality doesn't work like that. 

[Don Hills]

3 hours ago, jabbr said:

...

In the second case you are measuring the phase error of the DAC clock. which isn't itself in the audio frequency range. ...

 

I thought it extended all the way down to 0 Hz.

What is the other name for a constant phase error?

[unbalanced output]

Just opened this thread by accident. The discussion here resembles the one about class D amps. Somehow people get obsessed with meaningless measurements performed with inadequate equipment and who fail to appreciate how hard it is to switch from D to A world. The idea of the Regen is a great one, however it has its application. It will not improve every system, it will not be seen on many generic measurement tests.

 

Disclaimer:  I currently own no Uptone audio products nor I believe the Regen is needed for my DAC, however I can only be thankful for them that this option is there for those who may profit from it

[unbalanced output]

@jabbr, the idea is good however it may be trickier than it seems. When calculating an FFT, you're implicitly  smoothing out the effects of jitter since a typical FFT algorithm will assume nojitter in its own time increment. It seems to me you have to be significantly below the jitter error of the clocks youre trying to measure (i.e. with and without Regen) in order to get meaningful results. Just for the sake of demonstration, one could intentionally pick a bad clock. Im not sure if artificially adding jitter to the signal would be representative since it would never be a truly random sinal, however it would be a fun thing to do in the end.

 

[semente]

12 hours ago, mansr said:

Alex made it personal. He can fix that by selling a device to Amir.

 

I don't see why he should if he doesn't trust Amir's ability to perform meaningful, unbiased, measurements.

Which is not to say that I would not be interested in learning if people like the Regen's sound because it does what it's supposed to (isolate) or because it adds a "nice" coloration.

 

R

[mansr]

10 hours ago, Jud said:

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.

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.

[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.

[mmerrill99]

 

27 minutes ago, Jud said:

 

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?

I agree, Jud

 

What seems to be missing in this whole discussion, on both sides, is that doing relevant measurements, capable of revealing audible differences of the type reported for the ISO Regen requires focusing on the likely theory of operation & deriving a set of measurements that will best uncover whether this theory shows in the measurements.

 

To my way of thinking, Amir's approach lacks the necessary dedication & focus to achieve meaningful measurements. His measurements are cursory & generic in nature & people have to judge their validity. IMO, they would certainly not qualify as in any way definitive in answering the question of the audible effectiveness of this device.

 

It's interesting to note that those who seem to be so invested in measurements don't seem to be able to bring themselves to admit this aspect of measurements - they seem to talk about them as some sort of absolute & incontrovertible factor

[mansr]

8 minutes ago, Jud said:

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.

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?

[jabbr]

2 hours ago, unbalanced output said:

 

@jabbr, the idea is good however it may be trickier than it seems. When calculating an FFT, you're implicitly  smoothing out the effects of jitter

 

 

4 hours ago, Don Hills said:

thought it extended all the way down to 0 Hz.

What is the other name for a constant phase error?

 

Ok so there are two different measurements that we've been discussing and I need to clarify what is what:

 

1) Measure "jitter" or more properly phase error in the DAC clock: This is done with phase error measurement equipment. There are several ways to measure phase error using both analog and digital techniques, so-called "vector network analyzers", the venerable HP 3048A and newer equipment such as the John Miles TimePod as well as offerings from Keysight nee Agilent nee HP.

 

Phase error is provided as a plot : http://www.crystek.com/crystal/spec-sheets/clock/CCHD-575.pdf -- in this case the Agilent E5052A was used to take the measurements. See how the phase error rises as the offset frequency goes down? Thats called "close in" phase noise. Yes this phase error goes down to an offset frequency of zero. But phase error is always measured with respect to the clock frequency e.g. 11 Mhz, 22 Mhz. "Jitter" is 11 Mhz +/- offset where offset varies from 0 to ...

 

2) Measure the effects of jitter at the analogue output of the DAC: I've been discussing "line width" and widening of the peak in a number of recent posts. If you take a pure tone -- and for the sake of our discussion here, a 1KHz sine wave tone generated at 24 bits 352 kHz, or DSD256 or DSD512 (for the sake of our discussion) and take this digital stream and send it to the DAC, in an ideal situation the DAC will emit a pure 1kHz sine wave.

 

Phase noise, specifically close-in phase noise will cause a distortion in the output of the pure sine wave. What does this look like? It causes the "peak" in the spectrum to widen. That's called "linewidth". It goes up with increasing phase error. If we take the DAC output and run it through a spectrum analyzer such as the Audio Precision that "Amir" uses (quotes because i've never met him and he's not here  then what would be a thin line at the 1kHz frequency will spread out. This is caused by applying the phase error curve as above, to the pure tone.

 

Hopefully this makes more sense, and (2) is proposed as a way for folks who have a spectrum analyzer to measure the effects of clock jitter on the analogue output

 

3) I'm not being coy here: if the linewidth of a pure tone does not measurably widen with a high quality measurement e.g. not single Hz increments but let's say 0.1 Hz or better increments, then jitter at the DAC clock is not having an appreciable effect on the analogue output. I don't know that 0.1 Hz increments are the specific resolution needed but you know, basically if the 0.1 Hz phase error is not significant your clock is doing a great job

 

[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.

[jabbr]

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.

 

There are two sides to this coin:

 

1) Measurements are only good if the correct measurements are done. Any scientist worth their NaCl knows that someone doing a measurement with an agenda will produce skewed results. Even the choice about which measurements to perform or even which equipment to use can affect an agenda and skew results.

 

2) I agree that it is incumbent upon vendors to produce measurements, especially if the vendor is espousing "white papers" and theory of operation. We see all too much voodoo enshrined in pseudo-science and complicated engineering talk. Explanations that the measurements won't demonstrate are fine unless the vendor is espousing a particular mechanism of effect. 

 

3) I know that I discuss a lot of theory but I'm not selling anything, so my advice is free  and you get what you pay for  ... that said, I've considered commercializing certain things, but if I ever put my name behind a product (as opposed to consulting), it would be accompanied by extensive measurements (and also listening experience -- of course!)

[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.

[Don Hills]

20 minutes ago, jabbr said:

Ok so there are two different measurements that we've been discussing and I need to clarify what is what:

 

1) Measure "jitter" or more properly phase error in the DAC clock: ... 

 

... See how the phase error rises as the offset frequency goes down? Thats called "close in" phase noise. Yes this phase error goes down to an offset frequency of zero. But phase error is always measured with respect to the clock frequency e.g. 11 Mhz, 22 Mhz. "Jitter" is 11 Mhz +/- offset where offset varies from 0 to ...

 

2) Measure the effects of jitter at the analogue output of the DAC: I've been discussing "line width" and widening of the peak in a number of recent posts. ..

 

Phase noise, specifically close-in phase noise will cause a distortion in the output of the pure sine wave. What does this look like?...

 

 

For 1): ... So to my layman's mind, the other way of looking at this is that the clock is constantly speeding up and slowing down by random amounts. These speed variations are more pronounced over longer time periods. An analogy might be driving a car, and randomly stepping on the accelerator or brake. The longer you step, the greater the speed deviation. This neatly leads to your 2), where the analogue signal output of the DAC also varies in "speed" (frequency) as the clock speed varies. As you say, this is measurable.

 

Things get interesting when you try to determine what amount of variation is likely to be audible. There have been tests performed with different types of phase noise, and the worst audible case is still orders of magnitude beyond the performance of any competent DAC.

 

For example, most people seem to be quite comfortable with the "jitter" (wow and flutter) performance of turntables, although they are audibly bad. This is easily shown. Play a 1 KHz tone from a test LP. It sounds ok at first, then you start to notice small anomalies. It doesn't quite sound as solid and substantial  as it should. Then change to the same tone from a test CD or other digital source. The difference is not subtle. But the effect disappears when you compare music on the turntable and digital source, even though the same effects are present in the musc as were audible in the test tone.