UAC2 (USB Audio Class 2)
UAC2 is the USB Audio Class 2 standard - the driver-free protocol that lets modern USB DACs work with any operating system without vendor drivers. Supports up to 32-bit / 384 kHz PCM. If your DAC needs a special driver on Windows, it uses older UAC1.
UAC2 (USB Audio Class 2) is the standard USB protocol for audio devices. Any DAC that’s “USB Audio Class 2 compliant” works with:
- macOS (native, no driver)
- Linux (native, no driver)
- iOS/iPadOS (native)
- Android (native)
- Windows 10/11 (native since 2017)
vs older UAC1
UAC1 is limited to 24-bit / 96 kHz. UAC2 handles up to 32-bit / 384 kHz PCM plus DSD via DoP (DSD over PCM).
Why it matters
Older Windows (pre-2017) needed vendor drivers for hi-res USB DACs. On modern OS, any UAC2 DAC just plugs in and works. Simpler = better.
Check compatibility
DAC specs will state “UAC2 compliant” or “driver-free on macOS/Windows 10+”. All modern budget audiophile DACs (AIYIMA A80, FiiO K11, Fosi S3) are UAC2.
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