Pro Plus - popping when switching inputs

[loni_zg]

Pro Plus unit is connected with analogue output to power amp.
Occasionally popping sound comes from speakers when I change through inputs, at the moment after bluetooth goes from line in to optical in. Sometimes is louder sometimes is more quiet.
I found pattern where it always pops in my case:
- turn off/unplug the streamer from power, and power on streamer again
- when unit boot, I connect it with bluetooth (Tv - paired before)
- change input with remote to line, then to optical ... in that moment it pops through speaker.

After that, in use it may or may not pop occasionally, not loud as first time.
I notice also that streamer sometimes pops when using Audirvana for playback.

I report that to WiiM support, nothing from them so far.
If I had another Wiim unit, I guess I will need just 15 min to determine if it's software or hardware issue.
Any opinions or similar experience?

 

[loni_zg]

I returned unit yesterday.
Genaraly, Pro Plus is Ok streamer, features are fine, sound is mediocre (Argon Solo sounds better/same price)
From engineering standpoint, case was cheap, no any metal chassis, maybe to many resources spent on features to little on sound/build. It is Ok streamer for use with mid-fi audio systems.