Yes I have tested the D30 Pro with the optical output of a Google Chromecast Audio. Works perfectly. I also tested it with USB audio from a laptop - again works well. I've tested the TV optical output with a Beresford DAC (in fact this has been in use for >10 years) and again it works well.
I tested with an ARC extractor. So I took the HDMI (ARC) output of my TV into the ARC extractor, then the optical output from the ARC extractor into the D30 Pro optical input. It behaves exactly the same as when connected to the optical output of the TV -- the D30 Pro displays the sample rate...
Yes, I tried to explain in my original post: I've used the TV's optical output with a Beresford TC-7520 DAC for many years without issue. The Beresford is quite happy with the TV's output, the D30 Pro is not.
I've bought a Topping D30 Pro to use as a DAC and pre-amplifier between my television and my self-built Hypex UCD400HG power amplifier. The TV is a Panasonic TXP50V20B (12 year old Plasma display). Digital audio and video arrives at the TV from various sources over HDMI, the audio is then sent...