AudioQuest JitterBug FMJ USB 2.0 Data and Power Noise Filter at Vinyl Sound Toronto Canada

The JitterBug FMJ is a USB 2.0 data and power noise filter from AudioQuest (Irvine, California, USA), available at Vinyl Sound in Toronto, Canada. Engineered with Dual Discrete Noise-Dissipation Circuits, a Full Metal Jacket aluminium housing, and a carbon-loaded hinged noise-dissipation cover, the JitterBug FMJ is a purely passive device that requires no power from the USB hub. It addresses RF contamination on both the data and power lines of any USB 2.0 port, reducing jitter, parasitic resonances, and packet errors to deliver more spacious, detailed, and dynamic sound from USB audio systems.

Dual Discrete Noise-Dissipation Technology

At the heart of the JitterBug FMJ are two independent, discrete noise-dissipation circuits that simultaneously target RF noise on the USB data lines and the 5V VBUS power rail. Unlike a simple ferrite bead or a single-stage filter, the dual-circuit design treats interference in both the sending device (computer, streamer, or smartphone) and the receiving device (USB DAC or audio interface) at the same time. The result is a measurably cleaner differential signal that translates into blacker backgrounds, improved micro-detail retrieval, and greater dynamic contrast during playback.

Full Metal Jacket Housing and Carbon-Loaded Noise Cover

The FMJ designation reflects a meaningful engineering upgrade over AudioQuest's original JitterBug: a robust aluminium alloy sleeve that shields the internal passive circuitry from external environmental RF noise. Equally important is the hinged rubber door on the USB output port, constructed from a material substantially loaded with RF-absorbing carbon. When the JitterBug FMJ is used in parallel mode (plugged into an unused USB port with no downstream device connected), closing this carbon-loaded door prevents high-frequency noise from re-entering the system through the open female port, making the parallel configuration as effective as the in-line one.

Key Features

• Dual Discrete Noise-Dissipation Circuits: Two independent passive circuits reduce RF noise and parasitic resonances on both the USB data lines and the 5V power rail simultaneously, improving clarity in both the source and receiving electronics.
• Full Metal Jacket (FMJ) Aluminium Enclosure: A shielded alloy housing protects the internal circuitry from external environmental RF contamination, going beyond what a standard plastic-cased USB filter can achieve.
• Carbon-Loaded Hinged Noise-Dissipation Cover: The output port door is constructed from heavily RF-absorbing carbon material, further blocking noise ingress when the output port is unused during parallel operation.
• Passive Operation, Zero Power Draw: The JitterBug FMJ draws no power from the USB bus, ensuring it places no additional load on the host device and introduces no active noise of its own.
• Reduces Jitter and Packet Errors: By filtering differential noise from the data lines, the JitterBug FMJ reduces the signal-level disturbances that manifest as jitter and packet errors at the receiving DAC.
• In-Line and Parallel Operation: Use one unit in series between a computer or streamer and a USB DAC for primary noise filtering. Add a second unit in parallel to an unused USB port on the same hub for additional RF noise removal from the power bus.
• Compatible with AudioQuest DragonFly Series: Works in series with the DragonFly Black and DragonFly Red. When used with the DragonFly Cobalt (which already incorporates similar filtering), a second JitterBug FMJ in parallel mode provides further improvement.
• USB 2.0 Compliant, USB-A Connections: Fully compliant with USB 2.0 specifications and uses USB Type-A connectors (male plug on one end, female port on the other), compatible with laptops, desktop computers, NAS devices, streamers, and car audio USB ports.

Technical Specifications

Connections at a Glance

• USB Type-A male input: connects to host device (computer, streamer, NAS, car USB port, smartphone via adapter)
• USB Type-A female output: connects downstream to USB DAC or leaves port closed with carbon-loaded door for parallel use
• USB-C compatibility: use with AudioQuest's C-male to A-female adapter or DragonTail flexible adapter (sold separately) for USB-C-only hosts

Frequently Asked Questions

What is the AudioQuest JitterBug FMJ?

The AudioQuest JitterBug FMJ is a passive USB 2.0 data and power noise filter with Dual Discrete Noise-Dissipation Circuits and a Full Metal Jacket aluminium enclosure. It connects in-line or in-parallel to any USB audio chain, reducing RF noise, jitter, packet errors, and parasitic resonances on both the data and power lines of USB ports to improve sound quality from USB DACs and audio devices.

How does the JitterBug FMJ compare to the iFi Audio iSilencer Plus?

The AudioQuest JitterBug FMJ and the iFi Audio iSilencer Plus are the two most widely compared passive USB noise filters in the audiophile market. Both target USB VBUS and ground noise, but the JitterBug FMJ addresses the differential data lines more thoroughly using its dual discrete circuit design, while the iSilencer Plus takes a different topological approach. In head-to-head listening comparisons, the JitterBug FMJ is frequently noted for delivering a more three-dimensional soundstage and stronger body on instruments and vocals, while the iSilencer Plus is described as sounding comparatively flatter. The JitterBug FMJ is also available through authorised AudioQuest dealers across North America, making it particularly accessible in Canada.

Can the JitterBug FMJ be used in parallel as well as in-line?

Yes, the JitterBug FMJ supports both in-series and in-parallel operation. For primary noise filtering, place one unit in-line between the host device and the USB DAC. For additional improvement, plug a second JitterBug FMJ into any other unoccupied USB port on the same device or hub, with the carbon-loaded output door closed. This parallel configuration pulls further RF noise off the USB power bus, a technique that provides audible gains even on USB ports used only for charging or service functions.

What is AudioQuest's Dual Discrete Noise-Dissipation technology?

AudioQuest's Dual Discrete Noise-Dissipation technology uses two independent passive filter circuits built into a single device. One circuit addresses the differential USB data lines, reducing the signal-level disturbances that cause jitter and packet errors at the receiving DAC. The second circuit targets the 5V USB VBUS power rail, filtering the RF noise and parasitic resonances that the power supply of a computer, streamer, or smartphone injects into any connected audio component. Because both circuits operate simultaneously and independently, they treat noise at both the source and destination ends of the USB connection.

Is the JitterBug FMJ compatible with the AudioQuest DragonFly Cobalt?

The JitterBug FMJ is compatible with the DragonFly Cobalt, but with a specific recommendation. The DragonFly Cobalt already incorporates filtering similar to the JitterBug internally, so using one JitterBug FMJ in series with the Cobalt may help or affect performance depending on the specific host device and USB port quality. AudioQuest and dealers recommend experimenting with one unit in-line when pairing with the Cobalt. However, adding a second JitterBug FMJ in parallel to an unused USB port alongside any DragonFly model is consistently reported as a worthwhile improvement, as it reduces RF noise from the USB power bus regardless of the DAC's built-in filtering.

Where can I buy the AudioQuest JitterBug FMJ in Toronto or Canada?

The AudioQuest JitterBug FMJ is available at Vinyl Sound, an authorised AudioQuest dealer located in Toronto, Canada. Vinyl Sound carries the full AudioQuest lineup including USB accessories, DragonFly DACs, and cables, and can assist with questions about pairing, compatibility, and multi-unit configurations for your specific system.

What USB-C devices is the JitterBug FMJ compatible with?

The JitterBug FMJ uses USB Type-A connectors on both ends. For use with laptops, smartphones, or streamers that only offer USB-C ports, AudioQuest offers a compact C-male to A-female adapter. The AudioQuest DragonTail, a flexible USB-C to USB-A adapter included with the DragonFly Cobalt, also works. These adapters allow the JitterBug FMJ to be used across virtually all modern computing and mobile devices regardless of port type.

Does the JitterBug FMJ work with car audio USB ports and streaming devices?

Yes, the JitterBug FMJ is designed to work with car USB audio ports, laptop computers, desktop computers, NAS devices, and USB service ports on Ethernet streamers. Car audio systems and portable devices often have noisier USB implementations than dedicated home audio streamers, making them particularly good candidates for in-line JitterBug filtering. The passive design means no power is drawn from the host, so the JitterBug FMJ can be used with confidence across all of these applications.