I recently purchased a new Windows 8.1 desktop PC and combined it with a Schiit Modi USB DAC. I frequently experience clicks in the audio playback, but with rather peculiar behavior. I'm fairly certain that the "clicks" I hear are due to insufficient data being sent to the USB DAC, so that it has to fill in the gaps in the playback with a click or gap of some sort. I've been testing various changes for the past two days.
My computer was restarted after each change to guarantee the changes took effect.
These modifications have no effect:
-Changing USB port
-Changing USB port power settings
-Disabling all other devices on the same IRQ channel such that the USB DAC is alone on both its USB hub and IRQ
-Disabling antivirus and all other such processes/services
-Disabling all superfluous graphical effects
-Disconnecting all other external devices and replacing HDMI monitor with VGA
-Adjusting advanced system performance options to optimize performance of background services rather than programs
This modification affects audio playback, but has no effect on the "clicking" problem:
-Changing bit and sampling rate settings in the Windows advanced playback properties and/or in the media player options
This, bizarrely, appears to fix the clicking problem and allows my audio to play flawlessly:
-Keep a web browser window open
I'm not joking. If my media player is the only program open, then I hear a click about once per second. If I keep a Chrome window open along with my media player, then I can listen to music for hours and not hear a single click. I don't understand it, but I guess I've solved my problem. Considering how shaky this "fix" seems, though, I wouldn't be surprised if it stops working tomorrow.
I am using iTunes version 220.127.116.11 (that's a lot of ones) for playback. iTunes playback preferences are set to "Windows Audio Session", 44.1 kHz, 24-bit. Windows playback properties are also set to 44.1 kHz, 24-bit. All equalizer/effects are disabled in both iTunes and Windows. My USB 2.0 cable should be fine and is 6 ft long. Changing from "Windows Audio Session" to "Direct Sound" fixes the clicking problem, but produces crappier sound quality overall.