We are aware of the issues with the DPS driver in Windows 8 and newer machines. We are in the process of rebuilding the driver right now. But in the meantime:
When you quit DPS it should be switching back to your original output device automatically in Windows Sound Preferences. Are you saying there is still lag even when DPS is not running and the Default Output Device is not set to (Speakers) Digital Power Station?
Also, if you are using Adobe Audition or any other audio editing software, I recommend not using “Default Device” in the Audition audio setup window. When you allow Windows to route the audio, there is a chance for lag or other unreliable results. I recommend setting Audition’s outputs manually to connect directly to your output device of choice. This will also prevent it from interacting with the DPS driver.
Let me know how this works for you.