Windows Volume Control Disabled when K7 is Connected

[monofurioso]

OK, I'm an audio noob, so there must be a setting, or I inadvertently hit a button, but it's driving me crazy.

Everything had been working fine for the first few weeks w/ the K7 amp on my Win 11 PC. I could control audio volume/muting as per usual through Windows, but I could also adjust through the VOL/GAIN control knob on the K7.

Maybe I hit a button on the K7, but now Windows Volume control has absolutely zero effect on the volume. Hitting mute, or dragging the volume slider up and down does nothing. The VOL control knob on the Fosi does control volume. Also, if I'm watching, say a video, the Youtube volume slider works, but the system Win 11 volume is just non functional. As soon as I disconnect the K7 and go through another audio output, Win 11 volume control works fine.

Anyone with insight?

 

[Leonidas_k]

Do not have the K7, but is there any chance you have both USB and optical/coax cables connected to your PC?
If the USB port besides power can act as audio transfer connection, there is a chance that windows sees the K7 as two devices.
If that is the case, you can try to swap input/output devices to check which one is working with windows volume controls

 

[Massimo]

You need set UAC 1.0 Mode. See my review.

The UAC 1.0 mode provides microphone support with a fixed PCM 48kHz-16bit
output and is practically compatible with everything.
The second mode, called UAC 2.0, enables higher-quality audio via USB, up to
384kHz-32bit and DSD256, but requires specific configuration on Mac or
Windows.