USB2 High-Speed Isolator

Computer-based audio playback may not have the best audio quality through its USB interface. By default, laptops and desktops use switching-mode power supplies. For laptops, the DC jack uses 19V, but internally DC-DC converters are used to generate 12V, 5V, 3.3V and the lower voltages used by the motherboard. When audiophiles use 19V linear power supply for laptop used to play music connected to hi-fi system, the use of DC-DC converters internally resulted in less-than-desired sound quality when used for audio playback.

This is also true for serious computer-based music servers and streamers. If linear power supply is used through the motherboard’s ATX connector, voltages lower than 3.3V will be generated by the motherboard using DC-DC converter, causing the motherboard’s ground to be noisy.

One way to address this problem is to isolate the noisy ground. A separate 5V DC power supply which does not share the same DC ground with the computer is required. The USB signal is then regenerated / repeated, resulting in cleaner USB signal and better sound quality.

Using USB Isolator between computer and DAC

AA USB2 Isolator

Our USB2 High-Speed Isolator is based on Texas Instruments USB2 Isolator chip which provides 5kV isolation. Even if the USB DAC already have USB isolation implemented internally, the use of external USB2 Isolator may improve the sound quality further.

We have tested AA USB2 Isolator with the following DACs:

DACHas USB GND Isolation?Any SQ Improvement?
Holo May KTEYesYes
Denafrips Terminator PlusUnknownYes
Chord Hugo TT2 with MScalerUnknownYes
Chord Dave with MScalerUnknownYes
Marantz SA-10 USB B DAC InputYesYes
Matrix Audio xSabreUnknownYes
MSB ReferenceYes (ProUSB Input)No
AA USB2 Isolator DAC Tests

We have also tested AA USB2 Isolator with the following digital sources:

Digital Music SourceAny SQ Improvement?
Windows laptopYes
Intel NUCYes
Roon NucleusYes
Sony HAP-Z1ESYes
Innuos Zenith Mk2Yes
Lumin U1/U2 MiniYes
HiFi Rose RS250No
AA USB2 Isolator Digital Source Tests

The combination of digital source and USB DAC used will determine the final outcome whether AA USB2 Isolator is capable of improving the sound quality.

The USB2 High-Speed Isolator is now ready for order. These are the pictures of the latest version which can be used internally inside AA Music Server or used externally with any other music servers / streamers or laptops.

105 mm long
70 mm wide

The size is relatively small, even though it looks big in the pictures.

PCB slides into a Hammond extruded aluminum case
PCB taken out from the enclosure
From music server / laptop
Bottom view

The introductory price is RM1,200 without 5V DC LPSU. We plan to offer our own 5V 1.5A low-noise LPSU very soon.

AA USB2 Isolator is available for demo at Stars Picker Audio Library, Kota Damansara, PJ.