AQ Jitterbug Measurements

[Andre Marc]

I have seen a couple of very enthusiatic reviews over at CA with people using 2 JBs on the source: one in series, and the second on an unused port, and then feeding the Regen.

I have seen that as well. I am still hesitant about using 2 Jitterbugs, since theoretically one should suffice, but I would have to try it myself.

The REGEN will perform even better, the cleaner the data it receives, so that makes sense.

 

[YashN]

I have seen that as well. I am still hesitant about using 2 Jitterbugs, since theoretically one should suffice, but I would have to try it myself.

I think there's also sound theory behind why two would be better, with the second in a parallel port, but this is where the user feedback rather than the manufacturer description can be interesting as a confirmation in the field.

There is also a reason why more than two isn't recommended.

 

[Orb]

Just received my Hi-fi News magazine for the month and they reviewed the Jitterbug
The reviewer was John Bamford and he is a pretty good guy (if a product has a quirk or SQ problems he will say) and yeah he was very impressed, note he just used the one Jitterbug and with it plugged into the port he used.
From the measurements Paul Miller noted it can improve the rise time of the eye pattern, and reduce both jitter and noise of the DAC - key point here is that he tested a 'hub' powered DAC, however John Bamford did feel he noted it improved very well engineered DACs such as his own reference one (T+A DAC8).

Regarding the rise time improvement, Paul Miller did note that this was very relevant for one of his USB cables (has a bunch going back to when doing a group test and USB investigation) that was on the limit of the standard before the Jitterbug was installed and then comfortably within it afterwards, so this sort of ties in with Mike Lavorgna's experience with the Lightspeed cable stutter at higher rates being resolved with the Jitterbug.
Cheers
Orb

 

[jkeny]

OK so this has two filters - that makes sense as the common mode filter on the data signal is different to the filtering needed on the VBUS/GND.

Amir is correct, I feel - the circuit probably consists of some CM chokes on the data lines & inductors on the VBUS/GND lines - not something an engineer is going to be protective of the IP or bragging rights

 

[ar-t]

That is a bold claim, and needs to be backed up by facts and names. A post citing an anonymous source accusing Audioquest of being liars is
simply amateur hour. There has to be a higher standard.

"The design of Jitterbug involved a number of people including Gordon Rankin (who also designed the AudioQuest DragonFly DAC), and Steve Silberman, Garth Powell, Bill Low, and Joe Harley all from AudioQuest. Here's a bit more from AQ:

Gordon had been discussing ways to reduce the noise that plagues computing devices and it seemed clear to him that two distinct filters were needed: one to address the noise over the data line and a second to address the noise over the 5V power line. Additionally, Gordon had explored where such a device might be most effective and decided it should be at the host (computer), rather than at the client (DAC). Later, we learned that placing the filter at the host offered the additional benefit of using two filters (one in series and one in parallel) per bus, or of using USB filters on the unused ports of streaming devices."

http://www.audiostream.com/content/...b-data-power-noise-filter#BFbEf6Ziud55epKc.97

1.) He may have intentionally misled me.

2.) I may have intentionally misled my buddy. I really do have a cousin, who is some 6th-rate mafioso. Who is to say some of his bad habits have not rubbed off on me?

3.) "Discussing ways to reduce noise" and "involved" are not the same as "designing". "Involved a number of people" probably included me, to some extent, since I talk to several of those people. And I have discussed these very topics with them. I probably even measured something, at one time, without knowing what it is.

4.) Assuming I did measure something, what it was, what is is supposed to do, and who did what with it are not important to me. Sending us $ is all we care about. "You send stuff, we measure it." Simple as that.

5.) I have nothing to add to this, so do not try to drag me further into it. Anyone who does will be blacklisted. End of story.

And the last time I looked, Amateur Hour was some TV show, with Ted Mack.

 

[Andre Marc]

1.) He may have intentionally misled me.

2.) I may have intentionally misled my buddy. I really do have a cousin, who is some 6th-rate mafioso. Who is to say some of his bad habits have not rubbed off on me?

3.) "Discussing ways to reduce noise" and "involved" are not the same as "designing". "Involved a number of people" probably included me, to some extent, since I talk to several of those people. And I have discussed these very topics with them. I probably even measured something, at one time, without knowing what it is.

4.) Assuming I did measure something, what it was, what is is supposed to do, and who did what with it are not important to me. Sending us $ is all we care about. "You send stuff, we measure it." Simple as that.

5.) I have nothing to add to this, so do not try to drag me further into it. Anyone who does will be blacklisted. End of story.

And the last time I looked, Amateur Hour was some TV show, with Ted Mack.

Huh?

 

[Orb]

OK so this has two filters - that makes sense as the common mode filter on the data signal is different to the filtering needed on the VBUS/GND.

Amir is correct, I feel - the circuit probably consists of some CM chokes on the data lines & inductors on the VBUS/GND lines - not something an engineer is going to be protective of the IP or bragging rights

Considering its price did you expect much more?
OK did anyone actually at all bother reading that document I linked several times now , it shows what chokes and inductors to use, and relation of the GND lines within a PC and its subsidiary systems-bus
Once more unto the breach, dear friends once more : http://www.murata.com/~/media/webrenewal/support/library/catalog/products/emc/emifil/c35e.ashx
They also show some measurements applying filters, correct GND, and importantly limitations of suppressing noise for USB and its use.
Cheers
Orb

 

[YashN]

OK did anyone actually at all bother reading that document I linked several times now , it shows what chokes and inductors to use, and relation of the GND lines within a PC and its subsidiary systems-bus
Once more unto the breach, dear friends once more : http://www.murata.com/~/media/webrenewal/support/library/catalog/products/emc/emifil/c35e.ashx
They also show some measurements applying filters, correct GND, and importantly limitations of suppressing noise for USB and its use.

Yup read that before you posted any link to it: was researching the use of CMCs for USB. Excellent doc as it details several different implementations according to the device type.

Murata has a lot of cool info, some of it isn't in downloadable pdf though.

 

[wisnon]

I wonder how the JB compares to the iFi i-Purifier and the even more expensive Aubisque filter?

 

[Andre Marc]

I wonder how the JB compares to the iFi i-Purifier and the even more expensive Aubisque filter?

The iFi, as I understand it used at the host end, the Jitterbug at the source end.

 

[jkeny]

Huh?

We don't know if this is Pat or his alter-ego, mafioso cousin, Jocko so best not to ask questions

 

[jkeny]

Considering its price did you expect much more?
OK did anyone actually at all bother reading that document I linked several times now , it shows what chokes and inductors to use, and relation of the GND lines within a PC and its subsidiary systems-bus
Once more unto the breach, dear friends once more : http://www.murata.com/~/media/webrenewal/support/library/catalog/products/emc/emifil/c35e.ashx
They also show some measurements applying filters, correct GND, and importantly limitations of suppressing noise for USB and its use.
Cheers
Orb

Well I thought it was just some inductors on the Vbus & gnd - I didn't know that they had any CM chokes on the signal lines.
Yes, I had read the Murata document before - a very good doc detailing their range of offerings & the noise reduction measurements of each offering

 

[Andre Marc]

We don't know if this is Pat or his alter-ego, mafioso cousin, Jocko so best not to ask questions

LOL.

 

[Orb]

Yup read that before you posted any link to it: was researching the use of CMCs for USB. Excellent doc as it details several different implementations according to the device type.

Murata has a lot of cool info, some of it isn't in downloadable pdf though.

Yeah, sadly out of the loop for a few years now myself since retiring
Still nice them and a few other manufacturers do have some open guides/application notes if one knows where to sort of look to begin with.
Cheers
Orb

 

[dallasjustice]

Jocko Homo's cousin, maybe. The world's most intersting audio engineer, for sure!!

 

[jkeny]

Jocko Homo's cousin, maybe. The world's most intersting audio engineer, for sure!!

I agree he's interesting & funny too - don't know about the world's most interesting bit, though.

 

[Joe Whip]

I was able to get my hands on a second jitterbug, so I now have one in the port feeding the Wyrd and into the DAC and one in the unused USB port which happens to be right next to the Thunderbolt port which is what I sue to connect the SSD drive. I find that using a second Jitterbug further improve the sound. Adding a second gives you just a little bit of more of everything one Jitterbug gives you. On my system, I find that the use of the Jitterbug in the unused USB port gives the biggest improvement. perhaps because of its proximity to the Thunderbolt port? I look forward to hearing how they interact with my forthcoming DAC upgrade.

 

[Andre Marc]

I was able to get my hands on a second jitterbug, so I now have one in the port feeding the Wyrd and into the DAC and one in the unused USB port which happens to be right next to the Thunderbolt port which is what I sue to connect the SSD drive. I find that using a second Jitterbug further improve the sound. Adding a second gives you just a little bit of more of everything one Jitterbug gives you. On my system, I find that the use of the Jitterbug in the unused USB port gives the biggest improvement. perhaps because of its proximity to the Thunderbolt port? I look forward to hearing how they interact with my forthcoming DAC upgrade.

Thanks Joe:

I just got my Jitterbug but have not yet had time to plug it in.

I now have in house the SOtM USB hub, an UpTone REGEN, a Schit Wyrd, and some LAN filters.

 

[Elberoth]

Jocko Homo's cousin, maybe. The world's most intersting audio engineer, for sure!!

I love his posts

 

[Andre Marc]

JA published analog jitter measurements using the AQ jitterbug. I don't think the article is online yet since I just got the magazine in the mail yesterday.

JA's measutements showed no significant difference with the j Dunn jitter test. The ONLY repeatable differences were shown at inaudible levels whilst measuring the crappy AQ dragonfly. Two other more expensive DACs showed no difference.

Of course, many will say that JA's measurents don't matter because:
1. He didn't have specialized gear made by Tektronix designed to measure USB packet noise.
Or
2. Measurements don't matter because "I heard it."

Those who advocate the first objection may have a point. But I don't think it's very strong since listeners don't listen in digital. IMO, the burden is on the proponent claiming that a jitterbug can improve sound if that's what they are claiming. I've read all kinds of subjective opinions on various fora about the jitterbug, Schiit wyrd and the Uptone Regen. The claims being made are getting comical. I read one guy say that his bass had improved so much that he had to turn his sub down by 4db after interposing a USB regenerator. If that were true, it would be easy to measure these difference in the analog domain. Turns out, measurements once again prove elusive.

Is this a case of mass hysteria? Is everyone claiming to hear huge differences suffering from placebo effect? What do you think?

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."