Audioquest Jitterbug Passive USB 2.0 filter FMJ

AudioQuest JitterBug FMJ, or in full: Full Metal Jacket.

The metal-clad JitterBug offers better resistance to unwanted external interference, but is technically identical to the original AudioQuest JitterBug.

The JitterBug reduces contamination from RF noise generated by computers, cars, and other devices, whether used in series (series) or parallel. The JitterBug FMJ also takes a thorough approach to environmental RF interference that exploits this vulnerable interface.

The most noticeable change is the new metal housing - but the seemingly innocuous, hinged "rubber piece" that covers the JitterBug's output port also plays its part in the JitterBug's improved performance. This small black "door" is HF-tight because the material consists of highly HF-absorbing carbon.

Use a JitterBug in daisy chain between a computer, smartphone, NAS, streamer or car audio system and a USB input. For an additional sound improvement, use a second JitterBug in another, unused USB port parallel to the first - but here with the front door on the JitterBug FMJ closed.

Used in line with the DragonFlys Black or Red, the JitterBug helps these wonderful creatures fly higher and faster than before. If you want to use a JitterBug in front of a DragonFly Cobalt, however, it is advisable to experiment. Because the DragonFly Cobalt uses part of the JitterBug filtering, these two filters working in series can improve or degrade the playback - depending on the system and environment.

Regardless of the DragonFly model or other considerations, a second JitterBug used in parallel is always a welcome improvement as it pulls more RF noise from the USB power supply. This is how the JitterBug works, and why it makes significant improvements even when plugged into a service-only or update-only USB socket.