An introduction to computer audio
Some companies don’t use USB audio in isochronous transfer mode.
They implement their own solution using bulk mode transfer.
Bulk mode is asynchronous by design.
As it is bulk mode,
In case of isochronous mode it is exactly the reverse.
As long as the DAC is the only one connected to an internal hub, bandwidth is in general not the problem using USB high speed mode.
Inherent to a vendor specific solution is that he either supports your OS or not.
The advantage of USB audio is that it is natively supported by Win, OSX and Linux.
However in case of USB audio class 2 on Win you need a third party driver too.
Anyway this solution does audio over the USB without using the USB audio of the operating system.
High-speed asynchronous USB D/A converter
1x USB (USB female Type B)
16, 24, 32 bits
44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384 kHz
2 x S/PDIF (RCA and 75 Ohms BNC)
1x AES/EBU (XLR)
16 and 24 bits, 44.1, 48, 88.2, 96, 176.4, 192
1x optical (Toslink)
16 and 24 bits, 44.1, 48, 88.2, 96
SNR: 121dB (A weighted, 192kHz, 24 bits, 20kHz bandwidth)
THD+N: 0.0003% (192kHz, 24 bits)
Windows 7/ Vista /XP
OSX 10.6 Snow Leopard - 10.7 Lion compliant
Windows XP (from SP2), Vista, Vista 64, 7: Full ASIO multi-client operation of WDM and ASIO 2.0. WDM (DirectSound) with stereo and multi-Channel support.
Mac OS X (10.5 or higher) Intel: Core Audio, Core MIDI.
Using the same USB interface as his bigger brother.
More technical information about USB audio can be found here.