I2S 2:1 switching module

Right I don't remember for sure because swapped channels several times.

The other Simple DSD Modulator still worse, no music & a lot of noise in both channels in native DSD pass trought mode.

But both sounds pretty good with no noise converting PCM to DSD.
 
Is this correct:
You are using Amanero?
You have DSD_ON connected between the USB board and the DSD Converter?
You have MUTE connected between the USB board and the DSD Converter?
All the I2S wiring from the USB board to the DSD Converter board is very, very short length?
All the I2S signals from the USB board to the DSD Converter board is a dedicated ground just for that signal?
 
A fast 2-channel scope would definitely help to compare the input I2S signals to the output I2S signals. They should look the same, only slightly time shifted. But all should be time shifted by exactly the same amount, in which case there should be no problem.