AQ Jitterbug Measurements

dallasjustice

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Apr 12, 2011
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#21
Well thought out response, sir.

That being said. Addressing your points:

1-What is the "burden of proof"? Secondly, how do you define "wild claims" aside from the guy who said he had to turn down his sub by -4dB?

2-"Just because an RF engineer with a $40,000 Tektronix Lab Research piece of equipment says he can see an "improvement" in USB "packet noise", does NOT mean that anyone will be able to actually hear that "improvement" in the analog domain or there will actually be an "improvement" in the analog domain."

It also follows that it IS possible that there IS an improvement in the analog domain? No? Can't have one hypothesis without the other, no?
Andre,

To answer your question: Sure, anything is possible. I don't discount the possibility that the ear can hear something which standard analog measurement cannot yet reveal. That's a real possibility.

When I talk about "burden of proof", I am referring to my own standards. I don't expect other folks to agree with my standards. Having said that, I do think any claim which says there are was a 4db difference is bass is 100% the product of placebo effect. I only use that as an extreme example to make my point. There are folks posting under the influence of placebo effect (PUI). I am sure I am guilty of having done it myself over the years. In my world, if I can't be certain of something, I don't ever make any definitive statements about it. Other folks don't have standards. They just say whatever comes to mind and don't think about how others may use that information for their own purposes.

I remember a couple of years ago, I got the very first totaldac USB cable. Vincent sent it to me for free because I was a good customer and had bought a lot of expensive gear from him. I told a few folks that I had this cable and they wanted me to write a "review" about it. I never really said much about it. The reason is that I can't be certain that it really improved anything in my system. I still use the cable in my system even though I don't own any totaldac gear anymore. But I would never recommend that someone else buy it.
 
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Joe Whip

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Feb 8, 2014
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#22
Kind of sums up my view as well. I really have to be sure that I hear an improvement before I make any claims. If I have to think about it after listening really hard and running listening tests, then I just take it as no improvement or difference. If I think that I may or might hear a difference, I really don't and just move on. Think long, think wrong!
 

Orb

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Sep 8, 2010
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#23
I think I misread the graph on the MBP. The 1khz sinewave had alot fewer IM products when run off a battery, not the other way around. That makes more sense to me. I guess the A/C supply for the MBP is so bad it's able to cause pretty easily measureable distortion in the DAC.

Of course, I strongly believe taking measurements on a $150 DAC isn't "real world." I've taken alot of measurements using RMAA and my Lynx Hilo's analog input. I've tried a variety of servers and high-end power supplies. I've never seen ANY variation. However, I am working on measuring J test jitter using RMAA. Once I get it working, I will probably start a new thread and show different "tweaks" and how they may or may not have any affect on the analog output of a well designed DAC.

I think the best way to summarize my view on measurements related to digital is the following:

1. Just because I can't measure a change in the digital front-end using analog domain measurements, doesn't mean there aren't any changes. However, the burden of proof is still on those making the wild claims since the analog measurements create a presumptive impression for me, if there are no changes in the analog domain.

2. Just because an RF engineer with a $40,000 Tektronix Lab Research piece of equipment says he can see an "improvement" in USB "packet noise", does NOT mean that anyone will be able to actually hear that "improvement" in the analog domain or there will actually be an "improvement" in the analog domain.

Michael.
Did you just do a 1khz digital tone or a complete sweep of the 20hz-20khz?
Hi-fi News showed improve measurements with DACs quite a fair bit beyond $150 when doing their MacBook vs Melco N1A.
Thanks
Orb
 
Apr 3, 2010
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#24
Love to read the review when it comes online. I just put one on order and will do a test on my system/measurement.

For now, this kind of thing is very hard to evaluate since every system is different and this box by definition will have system dependent performance.
 

Andre Marc

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#25
Love to read the review when it comes online. I just put one on order and will do a test on my system/measurement.

For now, this kind of thing is very hard to evaluate since every system is different and this box by definition will have system dependent performance.
I don't believe it will be system dependent. There is not a single USB output on the market in any device that does not generate noise.
 

Andre Marc

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#26
Andre,

To answer your question: Sure, anything is possible. I don't discount the possibility that the ear can hear something which standard analog measurement cannot yet reveal. That's a real possibility.

When I talk about "burden of proof", I am referring to my own standards. I don't expect other folks to agree with my standards. Having said that, I do think any claim which says there are was a 4db difference is bass is 100% the product of placebo effect. I only use that as an extreme example to make my point. There are folks posting under the influence of placebo effect (PUI). I am sure I am guilty of having done it myself over the years. In my world, if I can't be certain of something, I don't ever make any definitive statements about it. Other folks don't have standards. They just say whatever comes to mind and don't think about how others may use that information for their own purposes.

I remember a couple of years ago, I got the very first totaldac USB cable. Vincent sent it to me for free because I was a good customer and had bought a lot of expensive gear from him. I told a few folks that I had this cable and they wanted me to write a "review" about it. I never really said much about it. The reason is that I can't be certain that it really improved anything in my system. I still use the cable in my system even though I don't own any totaldac gear anymore. But I would never recommend that someone else buy it.
Understood.

In essence USB audio has many, many issues, and this is why you are seeing many of these solutions appear.

Trust me I have had lots of laughs at some of the computer audio tweaks and fixes that have it the market, some of them absurdly priced.

But when a product works, and it is a modest upgrade, I take note.

BTW, when you see the usual online slobbering over products, it is easy to separate the credible posters from the shills and cheerleaders.
 

Orb

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Sep 8, 2010
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#27
I don't believe it will be system dependent. There is not a single USB output on the market in any device that does not generate noise.
But some DACs may have superior galvanic isolation, although I get the feeling it is not as clear cut as it seems; some with good engineering at the upper price mainstream/entry high-end tested (none so far tested without improvement but was limited check as part of the review) have been found to improve using the Melno USB connection compared to the MacBook.

Now it would be interesting to see the internal design of the Jitterbug compared to the Halide Bridge (or those equivalent to that design solution); Halide Bridge and comparable designs were noted for reducing noise from the USB, I appreciate these designs were for changing the interface to S/PDIF but same principle applies.
Cheers
Orb
 

Andre Marc

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#28
But some DACs may have superior galvanic isolation, although I get the feeling it is not as clear cut as it seems; some with good engineering at the upper price mainstream/entry high-end tested (none so far tested without improvement but was limited check as part of the review) have been found to improve using the Melno USB connection compared to the MacBook.

Now it would be interesting to see the internal design of the Jitterbug compared to the Halide Bridge (or those equivalent to that design solution); Halide Bridge and comparable designs were noted for reducing noise from the USB, I appreciate these designs were for changing the interface to S/PDIF but same principle applies.
Cheers
Orb
There in lies the biggest myth. Not a single DAC on the market offers true "galvanic isolation". This is a marketing term when used in high end audio.

Once you believe this premise, it changes the game.
 
Apr 3, 2010
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#29
I don't believe it will be system dependent. There is not a single USB output on the market in any device that does not generate noise.
Immunity of DACs to USB noise is different. That alone will create a situation where unless you test a good number of them, it is hard to make a universal statement.

Generated noise is also different from each computer and the nature of it. If the noise for example is coupling externally to the USB cable, it can do that just as well after this black box.
 

Andre Marc

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#30
Immunity of DACs to USB noise is different. That alone will create a situation where unless you test a good number of them, it is hard to make a universal statement.

Generated noise is also different from each computer and the nature of it. If the noise for example is coupling externally to the USB cable, it can do that just as well after this black box.
I highly suggest everyone reads this article by John Swenson, the main designer behind the UpTone REGEN and many other digital products:
http://uptoneaudio.com/pages/j-swenson-tech-corner

DISCLAIMER: I HAVE NO AFFILIATION, FINANCIAL, OR OTHERWISE WITH UpTone Audio. I purchased a REGEN at full price.
 
Apr 3, 2010
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#31
I highly suggest everyone reads this article by John Swenson, the main designer behind the UpTone REGEN and many other digital products:
http://uptoneaudio.com/pages/j-swenson-tech-corner

DISCLAIMER: I HAVE NO AFFILIATION, FINANCIAL, OR OTHERWISE WITH UpTone Audio. I purchased a REGEN at full price.
I like John and have no issues with what he is explaining. But what he is saying is fully quantifiable and he sadly has no numbers at all in there. It would take me two minutes to measure all of that and show the effect.
 

Andre Marc

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#32
I like John and have no issues with what he is explaining. But what he is saying is fully quantifiable and he sadly has no numbers at all in there. It would take me two minutes to measure all of that and show the effect.
Enough with the measuring.

What DAC, and USB source do you own, and wht USB filter/isolating products have you listened to?
 

mauidan

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Aug 2, 2010
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#33
I like John and have no issues with what he is explaining. But what he is saying is fully quantifiable and he sadly has no numbers at all in there. It would take me two minutes to measure all of that and show the effect.
I'm guessing he doesn't have the necessary test gear, or there would be measurements on the UpTone website.
 

Orb

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#34
Guys one other consideration before going at this; you need to ensure there is no additional influence caused by mains (the other connection to the devices that is usually forgotten about).
Yeah should be negligible and measurable for a product baseline but still need to make sure it is controlled environment (or at least how it is influenced), further compounded by switch mode PSUs (especially external ones).
Cheers
Orb
 
Apr 3, 2010
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#35
Enough with the measuring.

What DAC, and USB source do you own, and wht USB filter/isolating products have you listened to?
I have a Mark Levinson DAC driven by Berkeley USB to AES/EBU converter. I see no signature of USB noise as he is mentioning in there down to near -130 dbFS. I don't own a filter but as I said, I have the AQ one on order. Supposed to be here this week.

Note that I was trying to defend this category of product, not the other way around by saying that a single measurement of lack of effectiveness may not represent all combination of systems.
 

Andre Marc

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#36
I have a Mark Levinson DAC driven by Berkeley USB to AES/EBU converter. I see no signature of USB noise as he is mentioning in there down to near -130 dbFS. I don't own a filter but as I said, I have the AQ one on order. Supposed to be here this week.

Note that I was trying to defend this category of product, not the other way around by saying that a single measurement of lack of effectiveness may not represent all combination of systems.
Ok, a couple of questions. What is feeding the Berkeley? Why even do a conversion?

I would very much appreciate your listening impressions of the Jitterbug when it arrives. Mine is in transit as well.
 
Apr 3, 2010
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#37
Ok, a couple of questions. What is feeding the Berkeley? Why even do a conversion?
This is the Berkeley USB to AES/EBU bridge, not their DAC. I am using it to interface my computer to the ML DAC which doesn't have USB input.

I would very much appreciate your listening impressions of the Jitterbug when it arrives. Mine is in transit as well.
Will do :).
 

Orb

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Sep 8, 2010
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#38
This is the Berkeley USB to AES/EBU bridge, not their DAC. I am using it to interface my computer to the ML DAC which doesn't have USB input.


Will do :).
So in other words similar to the Halide Bridge (and comparable products) I mentioned earlier that would be interesting comparing internal design-componentry to the Jitterbug :)
Cheers
Orb
 
Apr 3, 2010
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Seattle, WA
#39
So in other words similar to the Halide Bridge (and comparable products) I mentioned earlier that would be interesting comparing internal design-componentry to the Jitterbug :)
Cheers
Orb
Yes. I also have the Audiophilleo USB to S/PDIF bridge that I will test with. I will also take apart the AQ and do a write up/show images of what is inside it. Time allowing, I will also scope out electrically and see what is there. Or isn't :).

How much are the other devices like it by the way?
 

Andre Marc

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#40
This is the Berkeley USB to AES/EBU bridge, not their DAC. I am using it to interface my computer to the ML DAC which doesn't have USB input.


Will do :).
Oh yes, I realize the BADA is a convertor. I assumed also the ML DAC is a legacy product with no USB input. An oldie but a goodie!! I believe
John Atkinson had this DAC for years as well.
 

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