Stop USB DAC Sleep Mode & Relay Clicks on Windows
Fix audio pops, relay clicking, and startup delay on Focusrite Scarlett, Topping, Schiit, Audioengine, FiiO, and MOTU USB DACs on Windows 11/10.
The USB Audio Class 2.0 Power State Problem
Modern audiophile DACs and professional studio interfaces use USB controllers (XMOS xCORE, C-Media Unison, Savitech) that adhere to **USB Selective Suspend**. When Windows audio output is silent for over 5–30 seconds, the OS signals the USB endpoint to transition from **Power State D0 (Active)** to **Power State D3 (Selective Suspend)**.
When audio resumes, waking the XMOS receiver and re-locking its crystal oscillator causes:
- Relay Clicking: Mechanical muting relays in Topping & Schiit DACs physical engage/disengage.
- Audio Transient Drops: The first 500ms to 1,500ms of audio is muted or cut off.
- Pops & Thumps: Sudden DC offset transitions during wake create audible pops in headphones/monitors.
Supported Hardware & DAC Models
Focusrite Scarlett
Scarlett 2i2, 4i4, Solo (Gen 2 / Gen 3 / Gen 4). Eliminates ASIO/WASAPI buffer initialization delay.
Topping & Schiit
Topping E30, D10s, DX3 Pro+ & Schiit Modi 3+, Modi+, Bifrost 2. Stops mechanical relay clicks when idle.
Audioengine & Edifier
Audioengine A2+, A5+, HD3 & Edifier R1280DB, S350DB. Keeps power-saving standby circuit disengaged.
FiiO, MOTU & iFi
FiiO K3/K5 Pro, MOTU M2/M4, iFi Zen DAC v2. Prevents XMOS USB driver idle suspend state.
Continuous Low-Frequency Carrier Stream
SpeakerKeepAlive streams an inaudible low-frequency carrier signal directly to WASAPI shared mode, maintaining USB Power State D0 continuously without system overhead.