I did an experiment the other day. I got fed up of all the audiophool networking aficianados telling me that I needed audiophile switches and cables because ethernet noise pollutes the DAC output. Yeah, whatever....
So I recorded a -120dBFs noise track in REW, converted it to flac and loaded it into Roon. With the DAC3 HGC in calibrated (0dBFS mode), I wound up the volume on the HPA4. At 0dB, there was nothing, zip, nada, SILENCE. At +4dB, I could hear a fain hiss from the tweeter (with my ear against it).
What was I hearing? Noise? A -120dBFS track? So I made another test track, this time with a -120dBFS 1 kHz 50% square wave.
Lo and behold, @ about +4 dB gain, I could hear........
wait for it........
the 1 kHz test tone!!!!!
Need to hook up my digital 'scope to the amp outputs and see what it looks like. Sure, there was some hiss with it, but the tone was unmistakeable. I'm honestly flabbergasted that a Benchmark DAC3 HGC, HPA4, and bridged AHB2s can pull an audibly recognisable 1 kHz tone out of a -120 dBFs test track.
Categorically proved that all this network noise/fibre isolation/LPS stuff is a load of hooey. Not only that, my endpoint is a humble RPi 4B with touch screen running Ropieee and powered over PoE by a PoE HAT which has a little SMPS on it.
Hats off to Benchmark Media for absolutely stunning performance!