AudioQuest JitterBug USB noise filter

I got an early start on computer audio. At the end of the last century I was using WinAmp with first a CardDeluxe PCI soundcard, then a similar card from RME, to play files on a Windows PC. After I became a MacPerson, I used FireWire audio interfaces from pro-audio company Metric Halo and an inexpensive USB-connected ADC/DAC from M-Audio. But it was with the USB version of Benchmark's DAC 1 that the computer began taking over from physical discs for my music listening. At first I used iTunes au naturel, but as I acquired more high-resolution files, I began using Pure Music to handle all the tedious audio housekeeping, assigning as a dedicated music server a G4 Mac mini I'd bought in 2006.

When Apple stopped supporting G4 machines in 2012, I bought, on the recommendation of Pure Music's Rob Robinson, a new Mac mini fitted with a 2.7GHz Intel i7 processor and 8GB of RAM. This I now run "headless"—ie, with no keyboard, mouse, or display—under the control, via our home network, of my MacBook Pro. I've used the mini as the primary source for all of my equipment reviews since 2012; it remained continuously powered up for almost three years without any problems until, one day this past June, it died.

According to the Apple Genius Bar near the Stereophile office, not only had the mini's internal power supply failed, its logic board was toast: It might take a week to repair it, depending on the availability of parts. Assuring the genius that I'd backed up my data with Apple's Time Machine utility, I left it with him and returned home to a week of playing CDs on my Ayre Acoustics C-5xeMP universal player.

Enter the JitterBug
This is when things got weird. Every disc I played sounded more solid, more corporeal than I remembered from the many times I'd played the same tracks from the Mac mini. The low frequencies sounded more authoritative, much as they had when I bought a Mark Levinson No.31 CD transport (now long since retired with mechanical problems). In hindsight, the system's sound with the computer-audio source now seemed consistently more ethereal. With one exception.

Before the Mac failed, I'd been experimenting with a sample of AudioQuest's JitterBug that I'd been given at the 2015 Consumer Electronics Show. The JitterBug, a small device costing $49, resembles a USB memory stick in size and appearance, except that it has a female Type-A USB port on the other end from the usual Type-A male plug. It is intended to be plugged into the computer's USB port, with the USB DAC plugged into its other end. According to AudioQuest, there is also a sonic benefit if a JitterBug is plugged into any unused USB port in any device that's connected to your system—even ports on devices that aren't in the direct signal path, such as a NAS or a router. However, AudioQuest warns against using more than two JitterBugs on one USB bus or in series.

Under the hood
The JitterBug is a purely passive device. All of its components—small numbers of surface-mount resistors, capacitors, inductors, and what appear to be common-mode chokes—are carried on a small, multilayer printed circuit board connecting the input and output ports. This board is housed in a plastic case just wide enough to prevent two JitterBugs from being plugged into the adjacent horizontal USB ports on my 2011 MacBook Pro. The case is also slightly too thick for two JitterBugs to be plugged, side by side, into the vertical USB ports on my Mac mini. (For my listening, I used a short USB extender cable to plug the second JitterBug into one of the ports of both computers.)

A USB connection comprises just four electrical contacts. The outer pair carries 5V DC (VBUS) and the supply ground; the inner pair carries the data signal in an antiphase, packet-based format, one element of this pair labeled Data Positive, the other Data Negative. When the positive data are at 3V, the negative data are at 0V, and vice versa, so that any noise contamination in the line will be common-mode and thus be rejected by the data receiver. The signal level doesn't change for a logic 1, but the signal level is inverted for each change to a logic 0. Each packet consists of a sync byte, followed by a packet-identification byte, then the data, and then error-checking bytes calculated from the data's content. If the error checking detects a problem in the packet's transmission, the receiver asks the source to resend that packet; otherwise, the source is asked to send the next packet. The USB receiver stores the incoming data in a temporary buffer before forwarding it to its destination.

AudioQuest says that the JitterBug conditions both the 5V voltage connection and the biphase data connections, restricting the connection's radio-frequency bandwidth to that appropriate for USB 2.0's maximum specified data rate of 480Mbits/s. As a result, there are said to be improvements in signal/noise ratio and reductions in jitter and parasitic resonances.

Listening
Back in October 2011, Stereophile spun off AudioStream.com, edited by Michael Lavorgna, to cover computer audio; earlier this year, Michael enthused over the AudioQuest JitterBug: "49 bucks buys you some of the soundest improvements I've heard for anywhere near the price." He later wrote, "I've now heard the JitterBug do its thing . . . a number of times in different systems and I easily heard sonic improvements each time." I have learned to trust Michael's ears. Even so, I wasn't expecting the degree of improvement the JitterBug wrought with the first recording I played, comparing the sound with and without the 'Bugs, via my newly repaired Mac mini. (The following comments are an amalgam of my experience with all the DACs I used for the comparisons.)

The low frequencies acquired more of the authority I experience with CDs. A song that has stuck with me for more than three decades is "Wallflower," from Peter Gabriel's fourth solo album, Security (original UK CD, Charisma 800 091-2). This very early (1986) CD suffers from the ills endemic to the primitive digital transfers of those days, but I've found that every improvement I make in my system pushes those ills a little further into the background. Listening to the ALAC file ripped from the CD, the dramatic tom-tom strokes that punctuate the buildup to the song's anthemic refrain sounded more solid, better defined in space and time, with the JitterBug. Similarly, with Phish's cover of Little Feat's "Time Loves a Hero," recorded live in 2010 (16/48 FLAC, downloaded from www.livephish.com), the drums and bass guitar both had more impact, and were better differentiated in the mix.

But it was in the midrange that the JitterBug most strenuously announced its presence. In my review of GamuT Audio's RS7 speaker elsewhere in this issue, I mention Leonard Shure's performance of Schubert's Piano Sonata in B-flat, D.960 (24-bit/96kHz WAV files). Antony Tommasini of the New York Times had written, of the CD of this performance (Audiofon CD 72010), that Shure's piano sounded clangorous in some of the most impassioned fortissimos. Without the JitterBug, yes, it does; with the JitterBug, the piano sounded more natural, more smooth in these passages.

The same was true with Martha Argerich's live performance of Rachmaninoff's Suite 2 for Two Pianos, with Gabriela Montero (ALAC files ripped from CD, Warner Classics 623594). Not only did the two pianos sound more liquid in the midrange with the JitterBug, there was a better sense of those pianos as physical objects/instruments in space. Similarly, the applause sounded more like hands clapping than generic noise.

These specific comments were all gleaned from my listening to the JitterBug in my big rig, with the PS Audio PerfectWave DirectStream and Bel Canto Black DACs. To check that I wasn't imagining things, I repeated much of my listening using a first-generation AudioQuest DragonFly and a Meridian Explorer, primarily with Sennheiser HD-650 headphones.

Overall, I would say that the JitterBug eliminated what I described as the "ethereal" character of computer audio, bringing it very close to what I experience from spinning CDs.

Conclusions
You can see from the "Measurements" sidebar that I could find no significant effect that the JitterBug had on the analog signals output by three of the DACs I had to hand. Yet with those DACs and others, I heard an improvement in sound quality that I can attribute only to the JitterBug. I hate when that happens!

Last June, Michael Lavorgna wrote that "measurements obviously have no direct correlation to enjoyment." I have no hesitation in declaring, loudly and longly, that I can think of no way to spend $49 that would make me more enjoy my computer-based audio than the AudioQuest JitterBug. Try one—or two—for yourself.

COMPANY INFO
AudioQuest
2621 White Road
Irvine, CA 92614
(949) 585-0111
ARTICLE CONTENTS

COMMENTS
doak's picture

Now combine it with an Uptone Audio Regen and hold onto your hat.
I am, simply, a VERY happy user. :D

AllanMarcus's picture

The Mac mini also has TOSLink out (via a mini plug). I'd be curious for you to try an optical cable and compare it to the USB, both with and without the JitterBug.

doak's picture

TOSlink tops out at PCM 24/96 and does not do DSD at all.
Hence, IMO, is not a "contender."

meloman11's picture

No measurable difference in jitter? Yet, Audioquest claims "measurably reduces jitter and packet errors".

BradleyP's picture

If it sounds different and there is no difference in the measurements then either your ears are fooling you OR you aren't measuring the right things OR your equipment isn't sensitive enough. Given the multiple reviews all reporting the same sonic improvements, I don't think you are fooling yourself. So, what do you think the difference is?

John Atkinson's picture
BradleyP wrote:
Given the multiple reviews all reporting the same sonic improvements, I don't think you are fooling yourself. So, what do you think the difference is?

If I knew, I would have reported that in the review. I used a very short, premium USB cable between the JitterBug and the DACs, but Gordon Rankin, the JitterBug's co-designer, has recently said that he finds it easier to measure the effect of the device by using a very long USB cable. That is something I need to try.

John Atkinson
Editor, Stereophile

doak's picture

Discussion with designers and "industry insiders" here:

>http://www.whatsbestforum.com/showthread.php?18311-AQ-Jitterbug-Measurem...<

John Atkinson's picture
doak wrote:
Discussion with designers and "industry insiders" here: www.whatsbestforum.com/showthread.php?18311-AQ-Jitterbug-Measurements/page2

I was puzzled by the HiFi News measurements, as Paul's eye-pattern graphs actually indicate that the JitterBug increases the risetime of the data waveform, not reduces it, which it looks as if he is saying. This actually what I would have expected given that the JitterBug low-pass filters the datastream.

However, by filtering out excessive RF noise on the data signal, this will presumably make life easier for the receiver at identifying bit transitions.

John Atkinson
Editor, Stereophile

tonykaz's picture

ghost writing for our JA?

Tony in Michigan

SN's picture

Today's measurements devices are more precise than our ears.
A big red SNAKE OIL ALERT should be shown if the gear's measurements clearly indicates no audible (positive) effect.

Regards,
your ears' and economy's best friend.

Venere 2's picture

It didn't take long for the measurement Talibans to show up.

It would seem that the editor of Stereophile, who has listened to thousands of different components over a career spanning decades, and who is also a musician; is fooling himself into believing he hears an improvement with the Jitterbug.

My ears have also been deceived by the Jitterbug. I guess I am better off believing some guy on the Internet...

tonykaz's picture

That makes it a nice little gizmo for the cable drawer if it doesn't work out.

This is Great 1980s Peg Board stuff for the Audiophile shops to help out with their paying Rent.

Back in the Day, little parts like this carried my Esoteric Audio Salon thru slow months of Summer.

Audiophiles love these little trinkets.

Monster Cable had a Full line of his kind of stuff, all were good sellers.

Jason Stoddard at Schiit is the onlyist one that po-po's all this junk.

The rest of us in the Business know fully well that Audiophiles are all about trinkets "moving the performance needle" after they shot their Wad on the Big Gear.

Litz headshell wires, tip-toes, Cramolin, directional Interconnects ( with Arrows ), Stainless, Nylon, Alum. headshell screws, Headshells by Koetsu, Fidelty Research and many others.

I had a 40' Wall of this stuff, all Audiophile rated and specific, it's amounts to a complete product line in and of itself. And, it's at least 50 points, plus nobody returns this stuff.

I even had customers that collect interconnects and speaker cables.

Phew, this IS HighEnd Audio ( the hobby ) : the Neurotic, Psychotic tendencies mechanically enabled.

But now we have Apple iTunes and DACs. Not a lot of gizmo stuff for "the" Wall.

I say: let em have their fun, nobody's gonna get hurt by this thing. Besides it's Audioquest taking over from Monster Cable, somebody gotta make and sell the Gizmos.

Noel Lee at Monster scored his Big with the Beats Headphone, it's time for somebody new.

Tony in Michigan

bernardperu's picture

Hi John, I know the Remedy Reclocker is USD$350 more expensive than the JB and it only does Toslink and Coaxial. But since you have used premium DACs, cables, etc, USD$350 is really not much.

Have you heard the Remedy? Would you prefer it to the JB?

Based on my experience (I also have the PS DirectStream), no single piece of gear (other than Speakers and matching Amps) makes such a great difference as the Remedy Reclocker, assuming one is to spend up to USD$3,000 on gear (I'd rather pair the Remedy with a USD$500 DAC than buying a USD$3,000 DAC and don't get me started on cables!)

Sorry for not talking about the Jitterbug, but they seem to compete.

If there is one question about the Jitterbug I would like to ask, it would be:

1) For my PS Directstream: Do I buy the Jitterbug + a 2m USD$50 USB cable or a USD$1,000 Audioquest USB cable?

Thanks!

doak's picture

IMO if it doesn't pass DSD, it's a non-starter.

barrysea's picture

I'm running audio files from my computer to the AQ Jitterbug, to Schitt's Uber-Bifrost and Asgard 2, through Senn HD650's, to my ears. JA was right, the music sounds great.

The Jitterbug is unbelievable, which many people will agree, but I say screw the measurements; trust your ears.

smileday's picture

I guess the computers JA used had good quality USB.

I can measure the difference in the quality of the USB digital audio outputs of my Mac mini (Late 2012) and my Toshiba laptop (Satellite P-50A). Even when I unplug the power adapter from my Toshiba laptop, the output from my Toshiba laptop is of poorer quality.
(Difference in jitter side bands or in spurious tones? I am not sure. It would be safe to say spurious tone.)

I measure it by looking at the spectrum of analogue audio output (20Hz – 20kHz, 20Hz – 50kHz, or 4kHz – 14kHz, etc.) of the connected outboard DAC. I used two $80 - $150 AD/DA converters sold in the musical instrument market: Behringer U-PHORIA UMC204HD, Focusrite Scarlett 2i2. Each product has both AD converter and DA converter.

Arthur.'s picture

Still, it's a nice product that offers an audiable improvement for basic users and for portable machines - that is if AudioQuest will ever snap out of their shell-shock and start shipping it before someone else invents something better - and many companies are planning to...

Eugene Gearty's picture

I have used the JB(X2) on 3 different systems for 2 days: My HiEnd system via a Benchmark USB DAC, my kitchen computer with a NuForce uDAC through Bose self powered speakers and my desktop office rig a Nuforce iDAC through a Zen Triode 3wt. amp.
I sincerely cannot tell the difference enough to make a $49.00 difference.
I have a considerable lot of money tied up in my HiEnd rig and have been doing this for 30 years so it's not about being cheap. Many times I have noticed improvements with various tweaks..
I'm just saying the packaging alone cost more then the JB itself.
This is NOT the way to keep the HiEnd industry on life support.
Perhaps 10 bucks or 2 for 15 bucks might make it so I don't have to pay the return shipping.

prerich45's picture

Ok, I've seen the measurements and all. I understand that science says this device does nothing, however, my ears tell me different. When I no longer have the sound of my mouse tracking, or keyboard typing, or hard drive working through my speakers.....somethings working!!!! It's dead quiet when not playing media!!!! Sounds better overall as well!!! I don't know what this thing is doing scientifically - and frankly, I don't care - it got rid of the annoying mouse/keyboard noise!!!!! Well worth the $48 I paid for it!!!!

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