Pro & Pro Plus - RCA In to Coax / Opt Out

[Witterings]

If I'm using the RCA input on a Pro or Pro Plus for lets call it "The 1st Device" device and then using the Optical out from the Pro or Pro Plus into say a Vibelink.
I'm guessing the fact the 1st device has already converted from Digital to Analogue will be ignored (as opposed to passed through), it'll be converted back to digital by the Pro / Pro Plus, then fed out as a digital signal to the Vibelink who's DAC will do the conversion?

If this is correct, might I be better off just using a digital out from the 1st device into the Pro / Pro Plus avoiding the 1st and the 2nd conversion and it'll just get passed straight through to the Vibelink which will then become the only conversion?

Real shame the Vibelink hasn't got auto input sensor the same as the streamers, I'm using that on one of my setups and works really well.

 

[harkpabst]

I'm guessing the fact the 1st device has already converted from Digital to Analogue will be ignored (as opposed to passed through), ...

If "The first device" is digital by nature and contains a DAC, then there is no way the digital source signal could be passed through its analogue RCA outputs. The devices DAC will always be in use (just like the ADC on the WiiM Pro or WiiM Pro Plus.

... it'll be converted back to digital by the Pro / Pro Plus, then fed out as a digital signal to the Vibelink who's DAC will do the conversion?

Correct.

If this is correct, might I be better off just using a digital out from the 1st device into the Pro / Pro Plus avoiding the 1st and the 2nd conversion and it'll just get passed straight through to the Vibelink which will then become the only conversion?

Probably yes, this will be measurably better. If it is really audible might be another question but there's no advantage to adding unneeded D2A and A2D conversions.

Real shame the Vibelink hasn't got auto input sensor the same as the streamers, I'm using that on one of my setups and works really well.

You can use the trigger output from the WiiM Pro Plus to the WiiM Vibelink Amp.

Edit:
In case you are asking for input switching on the Vibelink Amp then no, this is not possible. Your streamer should be the device all your sources are connected to.