Quick note on my equipment:
Schiit Audio- Bifrost (Uber)
Schiit Audio- Valhalla 2
AKG- K702 Anniversary addition.
The purpose of The Jitterbug is simple: reduce noise while improving audio quality. Does it work? Absolutely. First off, it does help as a USB filter. It reduces the amount of incoming noise and hum from a computer. The amount of noise reduced is not 100%. In fact, I noticed it varied but I would have to say it reduced somewhere around 50 – 75% of the noise coming from my USB. That may not seem like a lot, but that annoying hum went from being a serious detriment to my system, to being something I have to actively listen for. I use to have to turn my music louder than I would have liked because the hum was so distracting. Now I can have music at a very low volume and the hum is nearly gone. To be clear, if you simply want to reduce the hum from your USB, buying a ground isolator is probably your best bet, as that will reduce near 100% of the noise. Also having two Jitterbugs reduces the noise even more as they both actively work to clean your USB outputs.
The second thing the Jitterbug does, is to get you better sound. How does it work? Well without getting too technical, digital signals are susceptible to serious degradation. Most will tell you that digital signals are simple ones and zeros. This is true, but it is hardly simply. DAC’s can receive incorrect ones and zero sequences from the computer as it is transferred through the USB. In fact, this error in transfer is a big reason for distorted, muddy music. The simplest way to understand it is this; if your computer sends 22.214.171.124.1.1, but your DAC receives 126.96.36.199.1.0, the sequence is incorrect. Now your DAC still gets the music and can still play it, but I will be slightly off. A symbol won’t crash exactly the same as it should and guitars will lose some its pluck. This occurs also if your DAC has to guess what belongs in a missing section (188.8.131.52.1.?). All of this increases distortion. What the Jitterbug does, is try to maintain as much of the sequence as it can. Let’s theoretically say that it takes the sequence from only 75% correct to 85% correct. This means your DAC is now getting those missing (or incorrect) portions of information and outputting it to your headphones. Result? Better (or should I say less damaged) sound. The Jitterbug increases sound stage significantly which also allows instruments to live in their own specific space in your cans. I heard more crisp strings, tighter (not louder) bass, amplified and clearer vocals. Also more astute panning/direction of music whether computer made or live. In fact, the best way to hear the different is to listen to a live recording of an orchestra with and without the Jitterbug. You will notice how the instruments spread out more and are given more space to perform with the Jitterbug.
In closing, the Jitterbug is a good tool to reduce USB hum, but it really shines in opening sound stage, elevating instruments and playing your music from a darker, wider point. It is an absolute must for any computer headphone system. When being used with the Dragonfly Red for portable devices, it works wonders as well. The Dragonfly provides better, stronger power as the Jitterbug cleans and refines the signal. A true audio match. For only $50, this tool is an amazing addition to your music system. Listen to it for a while and go back to music without it. I guarantee you will never unplug it again.