AudioQuest JitterBug USB Filter Review

[Helicopter]

It’s not about the digital signal; it’s the RF/EMI noise that gets transmitted from the source through USB that’s causing the extra distortion. The actual data transferred is exactly the same.

Amir demonstrated the device does not change what is coming out of the DAC. If I put this between a computer and a printer, and the images from the printer are the same, then we know this is not improving anything. Same goes for a computer and a DAC. The printer and the DAC outputs are not being effected by RF/EMI, so it doesn't matter.

 

[Schmidlapper]

Funny how apt your spell check analogy actually is. The source is sending several things, typically one is power, and also data. That data is transmitted in the analog domain, and interpreted at the receiving end. It is in the interpretation stage that errors can be introduced.

Jitterbug goes somewhere in front of the DAC not after.

 

[Schmidlapper]

If I put this between a computer and a printer, and the images from the printer are the same, then we know this is not improving anything.

Huh?

 

[Helicopter]

Huh?

This thing is not capable of doing anything to a DAC that it doesn't do for a printer. A properly designed USB imput doesn't pass noise through the device. We can tell the jitterbug doesn't do anything because the analog output is the same with or without it.

If you expected this to work for audio but not for a printer then you probably misunderstand how USB works. If it will not improve print quality, then it won't improve audio either, and for the same reasons.

 

[100rounddrum]

This thing is not capable of doing anything to a DAC that it doesn't do for a printer. A properly designed USB imput doesn't pass noise through the device. We can tell the jitterbug doesn't do anything because the analog output is the same with or without it.

If you expected this to work for audio but not for a printer then you probably misunderstand how USB works. If it will not improve print quality, then it won't improve audio either, and for the same reasons.

Well that is, IF it’s properly designed.

This device is for those amps/dacs where it’s not.

 

[AudioSceptic]

Well that is, IF it’s properly designed.

This device is for those amps/dacs where it’s not.

Care to suggest a few examples?

 

[mansr]

Huh?

Uh-huh.

 

[100rounddrum]

Care to suggest a few examples?

I’m hearing a difference with the Topping D90.

 

[Helicopter]

I’m hearing a difference with the Topping D90.

Maybe try a blind AB test with a family member.

Or, do you have a printer with a USB input?

 

[tmtomh]

Funny how apt your spell check analogy actually is. The source is sending several things, typically one is power, and also data. That data is transmitted in the analog domain, and interpreted at the receiving end. It is in the interpretation stage that errors can be introduced.

Jitterbug goes somewhere in front of the DAC not after.

You are making a common mistake: the fact that digital data gets transmitted electrically (as voltages) does not mean it gets transmitted "in the analogue domain." The data remains digital, which is to say binary, which in turn means that the level of precision required to determine if a 1 or 0 is being transmitted across a wire is far less than the level of precision required to reproduce an analogue signal perfectly across a wire. If digital data were actually transmitted in analogue form (as opposed to merely electrical form), then none of us would even be having this conversation because there would be no internet.

More to the point, there are already tests out there online where people have done what you are asking for: run "normal," noisy USB sources into DACs with and without USB isolator products in the chain, to see the impact on the analogue output of the DAC. There's a really good one that uses the "eye patterns" that are a favorite among audiophile proponents of these devices but I can't lay my hands on it at the moment (I could've sworn @Archimago did such a test but so far I've been unable to find it over at his blog site).

But our own Amir ran such a test a couple of years ago, albeit without eye patterns, using as a source a typical laptop's USB output:

https://www.audiosciencereview.com/...s-of-intona-usb-isolator-for-audio-dacs.2616/

He found that if you use a terrible DAC, one USB isolator helped with low-frequency noise but not with jitter. The other USB isolator didn't help at all, and in fact added extra junk into the signal. Given that the cheapest USB isolator cost more than the crappy DAC in question, the lesson seems clear: competently designed DACs are more than capable of coping with a noisy USB source, and the USB isolators make no difference. The only scenario in which an isolator made a difference was if you paired a bad $150 DAC with a $229 isolator, which is of course silly since you can just buy a properly designed DAC for less than the combined price of those two and have your "USB isolation" built in to the DAC.

 

[Schmidlapper]

If you expected this to work for audio but not for a printer then you probably misunderstand how USB works. If it will not improve print quality, then it won't improve audio either, and for the same reasons.

Your use of the word improve, is what caught me off guard. What I have experienced is print jobs corrupted at some point during printing.

So far this has been just distraction regarding my original concern that the test did not include any representative of typical use sources and which the Jitterbug was marketed to help.

 

[tmtomh]

Your use of the word improve, is what caught me off guard. What I have experienced is print jobs corrupted at some point during printing.

So far this has been just distraction regarding my original concern that the test did not include any representative of typical use sources and which the Jitterbug was marketed to help.

I get what you are saying, and for the benefit of others I will try to make it as clear as possible: You are hypothesizing that USB isolators/decrappifiers are ineffective at removing noise and jitter from the USB signal path because the source Amir is using is his AP Analyzer, which has very low noise and jitter to begin with - in other words, there is basically nothing there to filter in the first place.

I see the logic of your point there, and would refer you to my comment just above, where I link to a test Amir did with the kind of source you are asking about - in that case, the USB port of an HP laptop.

 

[Schmidlapper]

tmtomh your comments have been the most interesting and helpful regarding my original question. I try to stay out of the weeds because as soon as you enter you will say something that isn't wholly accurate or even accurate at all and then that becomes the focus of the conversation. You have graciously pointed out my inaccuracies, yet stayed on the subject, so I salute you.

Peace to all and to all a good night.

 

[Helicopter]

...
Peace to all and to all a good night.

Thanks. You too.

 

[amirm]

In actual use the audio is coming from a source which is fed to the DAC via USB cable. The source is generally a CD player, PC server, audio streamer or similar. You would use one of them as an external source for the data going in to the DAC and measure the DACs output with and without a Jitterbug installed to determine if it affects the output.

That is precisely the nature of the testing I performed. The PC in all cases was providing the USB signal. My "lab grade" device is only testing the analog output of the DAC. It is NOT the source of signal to DAC, jitterbug or combination thereof.

The analyzer is replacing your amplifier, speaker and ears, not the source.

 

[Chrispy]

Just expecting something real from Fraudioquest is the initial problem

 

[Schmidlapper]

That is precisely the nature of the testing I performed. The PC in all cases was providing the USB signal.

Thanks for the clarification amirm, I have no issue then with the test results as presented and apologize for any confusion.

 

[AudioSceptic]

Thanks for the clarification amirm, I have no issue then with the test results as presented and apologize for any confusion.

Good. I thought all along that you must be not getting what Amir's test entailed.

 

[Killingbeans]

Thanks, isn’t it the source signal the Jitterbug has any influence upon, not the DAC performance, correct?

The DAC performance is the only link in the chain that gives you an indication of audible difference.

The Jitterbug is marketed a product that assists the DAC in doing one of its functions, namely mitigating the effects of jitter from source + transmission. But the test showed that it fails to help even a "bad" DAC like the Schiit Modi 2.

Also, the teardown shows that the Jitterbug isn't anything but a simple passive filter. It does nothing that any modern run-of-the-mill DAC shouldn't already do 100 times better on its own.

Well, if you have a lot of source noise, the sound gets bright in a fatiguing way, and therefore you have more “nasties” than a filtered power source..

Why would parasitic noise from the USB power rail elevate the treble?

Or is the general consensus here that USB noise is a myth?

Other than ground loops, noise via USB should only be of concern if the DAC is exceptionally badly engineered.

 

[Veri]

Also, the teardown shows that the Jitterbug isn't anything but a simple passive filter. It does nothing that any modern run-of-the-mill DAC shouldn't already do 100 times better on its own.

This. Even if you want to believe, want to rely on your empirical experiment of using one, the truth is that this thing cannot possibly do much... shame on audioquest, but I guess the people buying these things and thinking they "improve" so much are partly to blame for being so gullible.