@audphile1 - I’m interested by your description of the sonic signature of optical, as I currently have a system which is a touch too warm, with overemphasised mid-range.
This is totally my fault as I selected the USB cable (FTA Sinope - warmish, enhanced midrange) when I had some ATC SCM19s on loan from the dealer. When my SCM40s finally arrived I realised I had underestimated the warmth they impart on the sound compared to the dry 19s. However, I plan to give the 40s and Sinope a thorough burn in, and then address the USB issue first. I might ask NA nicely if I can try again their Muon USB - which I had previously rejected as being too aggressive, detailed and forward.
I think next I will try a budget optical setup (links below) to determine if the sonic characteristics work well. And if they are then gradually upgrade the components. And if not, then have a chat with NA regarding their Muon and Eno systems.
I would add that I’m finding to very tricky getting the sonic signature correct. It feels like such a fine line between too bright and too warm.
https://smile.amazon.co.uk/TP-LINK-MC220L-Supporting-MiniGBIC-Modules/dp/B001GQDRWK
https://smile.amazon.co.uk/KOMQI-135501061-TP-LINK-TL-SM311LM-MiniGBIC/dp/B001800S6M
https://smile.amazon.co.uk/StarTech-com-Fiber-Optic-Cable-Multimode-BLACK/dp/B00015G9SG
https://smile.amazon.co.uk/dp/B08Y59FXDZ/ref=twister_B08Y5GRZR4?_encoding=UTF8&psc=1