AQ Jitterbug Measurements

[dallasjustice]

With a well engineered USB DAC, data stream rise time is irrelevant to what comes out of a DAC. That's what JA's measurements revealed. I look forward to Amir's measurements as well. Feel free to believe as you wish. I'll stand by what I said.

Michael.

FYI, HiFi News & Record Review just published measurements of the Jitterbug saying it clearly made a positive difference in rise time and reduced jitter.

Also Gordon Rankin posted on several board about his explicit involvement in the design. Perhaps you and your buddy should post an apology for the
cavalier remark about having "heard" he did not design it?

"We did allot of research on the damn thing. We made boards that could be reconfigured into about 10 different devices, then we tweaked and tweaked some more.

Then we gave the resident sound guy Joe Harley all of them and he picked this one out as the best sounding."

 

[microstrip]

Thinks become much funnier when you mix two devices: http://www.audiostream.com/content/usb-accessory-roundup-uptone-audio-usb-regen-audioquest-jitterbug-schiit-wyrd.

 

[Andre Marc]

With a well engineered USB DAC, data stream rise time is irrelevant to what comes out of a DAC. That's what JA's measurements revealed. I look forward to Amir's measurements as well. Feel free to believe as you wish. I'll stand by what I said.

Michael.

That is the type of nonsensical answer that starts a 1000 internet debates. What is a "well engineered" USB DAC?

Who says the data stream rise time is irrelevant? Everything matters! You did not address the jitter measurement.

Back to the design, so you are saying Gordon Rankin and audioquest are lying about his involvement? I am unclear.

 

[DaveyF]

With a well engineered USB DAC, data stream rise time is irrelevant to what comes out of a DAC. That's what JA's measurements revealed. I look forward to Amir's measurements as well. Feel free to believe as you wish. I'll stand by what I said.

Michael.

I don't understand that comment either. Please elaborate how JA's measurement's revealed this to be the case.

 

[dallasjustice]

"Everything matters". Is this where I'm supposed to turn my brain off?

Actually, it doesn't. If you know how a well engineered USB receiver works, you would know the rise time on the square wave ONLY matters to the extent it produces a data error.

If you read what I said about Gordon and what AQ says about who designed the jitterbug, you would find they are consistent statements.

That is the type of nonsensical answer that starts a 1000 internet debates. What is a "well engineered" USB DAC?

Who says the data stream rise time is irrelevant? Everything matters! You did not address the jitter measurement.

Back to the design, so you are saying Gordon Rankin and audioquest are lying about his involvement? I am unclear.

 

[Andre Marc]

"Everything matters". Is this where I'm supposed to turn my brain off?

Actually, it doesn't. If you know how a well engineered USB receiver works, you would know the rise time on the square wave ONLY matters to the extent it produces a data error.

If you read what I said about Gordon and what AQ says about who designed the jitterbug, you would find they are consistent statements.

"My RF engineering mafia friend tells me that Gordon Rankin wasn't the jitterbucks designer."

This is clear as day. So the answer is you are calling both parties liars. Own up to it and don't do a dance.

 

[dallasjustice]

http://i.word.com/idictionary/The
Read definition 1b.

Andre, are you THE reviewer of ToneAudio?
http://www.tonepublications.com/staff/

"My RF engineering mafia friend tells me that Gordon Rankin wasn't the jitterbucks designer."

This is clear as day. So the answer is you are calling both parties liars. Own up to it and don't do a dance.

 

[Andre Marc]

"Everything matters". Is this where I'm supposed to turn my brain off?

Actually, it doesn't. If you know how a well engineered USB receiver works, you would know the rise time on the square wave ONLY matters to the extent it produces a data error.

If you read what I said about Gordon and what AQ says about who designed the jitterbug, you would find they are consistent statements.

My friend you stepped in a pile of s h i t and now you have to wiggle and distract. That is a game for one. LOL.

 

[dallasjustice]

I'm not your friend.

My friend you stepped in a pile of s h i t and now you have to wiggle and distract. That is a game for one. LOL.

 

[Andre Marc]

I'm not your friend.

awww...

 

[DaveyF]

Mr Justice....please elaborate as how JW's measurements reveal how the data rise stream is irrelevant to what comes out of a DAC! BTW, do you not think that if the rise time on a square wave produces data error that that is not relevant?? Please explain that one too.

 

[amirm]

I am going to remind members that we are in Michael's dedicated forum. Please be respectful to him, regardless of how much you disagree. You can create threads elsewhere and say what is on your mind (which I still hope will be respectful).

 

[dallasjustice]

To be more clear, JA's measurements are about as good as they get in the analog domain to measure jitter. They showed NO CHANGE in the j Dunn test with two well engineered DACs. Maybe there is a difference. Who really knows? But it can't be measured in the analog domain.

All the other measurements Andre is talking about are digital square waves. The data stream clock inside the DAC controls the flow of data. The square waves tell the DAC either a one or a zero. As long as the square wave accurately represents the one or the zero, the data stream arrives the same as it was on the computer's hard drive(rise time irrelevant). This has been demonstrated numerous times. There's no debating this.

The only remaining question is jitter. If the USB receiver properly controls the data stream, there's really nothing a computer can do to affect the jitter inside the DAC.

Many have postulated logical explanations as to why these USB reclockers could help jitter. But nobody has ever proven their claim with a measurement in the analog domain. Maybe it's there. But there's no independent support for any of these hysterical claims.

So, I remain skeptical.

I don't understand that comment either. Please elaborate how JA's measurement's revealed this to be the case.

 

[Orb]

With a well engineered USB DAC, data stream rise time is irrelevant to what comes out of a DAC. That's what JA's measurements revealed. I look forward to Amir's measurements as well. Feel free to believe as you wish. I'll stand by what I said.

Michael.

Just a heads up, JA used to use one of Paul Miller's (editor and test-measurement guy at Hi-fi News) designed measurement suite tools before he had the latest AP - even so the Miller Audio suite he owned was quite old.
The rise time and eye pattern is important, and one reason why the review on audiostream showed how one cable worked at higher sampling rates with it in but failed with the Jitterbug removed (something about that cable is not fully ok IMO but worked better with the Jitterbug improvement to the digital eye measurements).

In many ways Paul Miller's knowledge-experience with digital associated measurements to a greater degree than JA, and that is saying something as I have a lot of respect for JA from a technical and knowledge-expertise perspective.
And you are aware Paul Miller is also measuring in the anlogue domain, and as I mentioned before one of the other regen products where their engineers look at all aspects of measurements from eye pattern to jitter-noise in analogue domain just like Paul Miller did.
IMO the key aspect here is scope-focus on what your active components are with the product, unfortunately it is not enough to look at just a limited few great engineered products and without considering other environments and say it shows the regen does nothing
Cheers
Orb

 

[Andre Marc]

To be more clear, JA's measurements are about as good as they get in the analog domain to measure jitter. They showed NO CHANGE in the j Dunn test with two well engineered DACs. Maybe there is a difference. Who really knows? But it can't be measured in the analog domain.

All the other measurements Andre is talking about are digital square waves. The data stream clock inside the DAC controls the flow of data. The square waves tell the DAC either a one or a zero. As long as the square wave accurately represents the one or the zero, the data stream arrives the same as it was on the computer's hard drive(rise time irrelevant). This has been demonstrated numerous times. There's no debating this.

The only remaining question is jitter. If the USB receiver properly controls the data stream, there's really nothing a computer can do to affect the jitter inside the DAC.

Many have postulated logical explanations as to why these USB reclockers could help jitter. But nobody has ever proven their claim with a measurement in the analog domain. Maybe it's there. But there's no independent support for any of these hysterical claims.

So, I remain skeptical.

Michael, I at least appreciate you clearly stating your position, thank you.

I don't think it corellates to real world conditions.

"..there's really nothing a computer can do to affect the jitter inside the DAC."

If this is true, the UpTone REGEN would have absolutely no effect and would be snake oil. It is not. (I know you initially referred to hearing
any differences with the REGEN as "hysteria".)

The same applies to USB cables. There would be no difference between a $5 Belkin and a $250 DH Labs. This again is not the reality.

My point is posting definitively based on theory and not experience is a tightrope.

"As long as the square wave accurately represents the one or the zero, the data stream arrives the same as it was on the computer's hard drive(rise time irrelevant). This has been demonstrated numerous times. There's no debating this. "

This IS for debate. Maybe I am nuts, but this sure sounds like "bits are bits" to me.

 

[amirm]

FYI, HiFi News & Record Review just published measurements of the Jitterbug saying it clearly made a positive difference in rise time and reduced jitter.

I just read the measurement section of that review and I would not at all get excited about what is there. Here is the snapshot:

The eye pattern was great before the insertion of the AQ (top graph) and just as great after (the middle). The difference in rise time is not material at all in this context. As long as the "eye" (open area between the waveforms) is clear -- and this one could not be more open/clear -- it makes no difference at all in data recovery. This is one solid, reliable connection in need of no improvement whatsoever. Here is some context:

The eye pattern on the right is what we worry about. The one that is on the left is an example of a good pattern which is much noisier than HiFi News example.

As to reduced analog jitter, one needs to read the fine print. They used an AQ DAC (Dragonfly)that relied on USB for its power. So no doubt cleaning that line makes a bit of difference and a bit it was. Jitter went down from very low 220 picoseconds to 166 or some such numbers. These are all in the same category and at any rate, not representative of any high-performance DAC or USB adapter with its own power supply. Here is the Dragonfly:

If yours resembles that DAC, and you care about such small differences in jitter, then yes, it is time for celebration now .

Seriously, I am in the process of setting up my lab so I will post my own measurements but for now, I don't recommend anyone get excited over these objective results.

 

[Andre Marc]

I just read the measurement section of that review and I would not at all get excited about what is there. Here is the snapshot:

The eye pattern was great before the insertion of the AQ (top graph) and just as great after (the middle). The difference in rise time is not material at all in this context. As long as the "eye" (open area between the waveforms) is clear -- and this one could not be more open/clear -- it makes no difference at all in data recovery. This is one solid, reliable connection in need of no improvement whatsoever. Here is some context:

The eye pattern on the right is what we worry about. The one that is on the left is an example of a good pattern which is much noisier than HiFi News example.

As to reduced analog jitter, one needs to read the fine print. They used an AQ DAC (Dragonfly)that relied on USB for its power. So no doubt cleaning that line makes a bit of difference and a bit it was. Jitter went down from very low 220 picoseconds to 166 or some such numbers. These are all in the same category and at any rate, not representative of any high-performance DAC or USB adapter with its own power supply. Here is the Dragonfly:

If yours resembles that DAC, and you care about such small differences in jitter, then yes, it is time for celebration now .

Seriously, I am in the process of setting up my lab so I will post my own measurements but for now, I don't recommend anyone get excited over these objective results.

Amir, thanks a bunch for posting this. HiFi News online is premium content only, not free, like sphile. I am assuming those are scans! Any issue with posting the rest?

Thanks for your interpretation of the results. I very much look forward to your lab being set up as well.

 

[amirm]

Amir, thanks a bunch for posting this. HiFi News online is premium content only, not free, like sphile. I am assuming those are scans! Any issue with posting the rest?

My pleasure. These are screen snapshots from my digital subscription. Under Fair Use doctrine in US, this is allowed but full copy of the article would obviously not qualify. So I hope you understand me not doing posting the full article (which is all subjective and unrelated to the measurement section). Digital subscription is pricey (37 pounds or $57) but given the unique work that Paul Miller does, is perhaps justified .

 

[Andre Marc]

My pleasure. These are screen snapshots from my digital subscription. Under Fair Use doctrine in US, this is allowed but full copy of the article would obviously not qualify. So I hope you understand me not doing posting the full article (which is all subjective and unrelated to the measurement section). Digital subscription is pricey (37 pounds or $57) but given the unique work that Paul Miller does, is perhaps justified .

Yes, totally understandable. I knew it would be a stretch..figured I would ask!

 

[dallasjustice]

The jitter measurements look very much the same as JA's measurement. Did Paul Miller also measure with a better quality DAC? The higher quality DACs JA measured showed no difference at all.

It would interesting to see the result using your Berkeley alpha, which I think is Gordon's finest work.

I just read the measurement section of that review and I would not at all get excited about what is there. Here is the snapshot:

The eye pattern was great before the insertion of the AQ (top graph) and just as great after (the middle). The difference in rise time is not material at all in this context. As long as the "eye" (open area between the waveforms) is clear -- and this one could not be more open/clear -- it makes no difference at all in data recovery. This is one solid, reliable connection in need of no improvement whatsoever. Here is some context:

The eye pattern on the right is what we worry about. The one that is on the left is an example of a good pattern which is much noisier than HiFi News example.

As to reduced analog jitter, one needs to read the fine print. They used an AQ DAC (Dragonfly)that relied on USB for its power. So no doubt cleaning that line makes a bit of difference and a bit it was. Jitter went down from very low 220 picoseconds to 166 or some such numbers. These are all in the same category and at any rate, not representative of any high-performance DAC or USB adapter with its own power supply. Here is the Dragonfly:

If yours resembles that DAC, and you care about such small differences in jitter, then yes, it is time for celebration now .

Seriously, I am in the process of setting up my lab so I will post my own measurements but for now, I don't recommend anyone get excited over these objective results.