There are claims that sound quality improves by having a full galvanic isolation between the PC and the DAC. Some manufacturers of USB DACs use opto-couplers to eliminate the noise from the USB connection.

Exasound provided some measurements demonstrating the difference galvanic isolation can make.


Please note that although USB2 is supported by virtually every isolator, this does not mean that all USB speeds are also supported. A DAC that can play > 96 kHz needs High-Speed ​​(480 Mbps). Cheap isolators and extenders are often limited to Full Speed.


Optocouplers are used for galvanic isolation. Of course you can also send the signal via a fiber optic cable.
This makes it possible to use a cable length greater than the 5 meters that the USB standard allows.
This is a technology employed by a couple of extenders.


Uptone Audio took matters a bit further. Their Regen is not a isolatoronly but a re-clocker as well. It re-generates the USB stream.
Their Regen generated quite a stir at various audio forums.

Likewise the Audioquest Jitterbug.


AmirM measured the jitterperformance of the Regen and the Jitterbug.

His conclusion:

We can easily demonstrate that devices like JitterBug cannot work. USB is a high-speed bus. You cannot filter it without causing the data to be corrupted. So any filtering that JitterBug performs there must be well into Megahertz region and hence outside of audible band. Since data transmission to a USB DAC is highly reliable anyway, filter does no good. As to filtering of the USB power, the DAC itself has a regulator and filter of its own. Adding the tiny bit of filtering JitterBug has is like spitting in an ocean and expecting its level to rise.


Please save your money folks. Give it to Charity. Go have a great dinner. Anything but rewarding people who build these useless devices that attempt to solve problems that don't exist.


AudioQuest JitterBug USB Filter Review - AmirM

Although the manufacturers of these products wax away about the improvements in audio quality, most of them don’t supply measurements.


USB Cleaner

USB Cleaner

Ground loop

Sometimes people complain about static noise while browsing. Often this is a ground loop. Gaming PC's with a fast GPU are prone to it.
If this is the case, a USB isolator can help.

Fortunately, a good insulator is not expensive, $70 will do.

USB Noise / Ground Loop - Best Solution -

Topping HS01

High speed compatible isolater.

MEASUREMENTS: Topping HS01 - USB 2.0 Isolator & Ground Loop Eliminator - Archimago 2022

Added 2023

Hifime High-Speed USB Isolator v2

USB Highspeed compatible isolator


Hifime High-Speed USB Isolator v2

Added 2023