Continuing experimentation with optical continues causing me to reassess its value in all instances. I've been using generic FMC, with lps and quality power cables prior to server for past month or so, thought I had pretty good handle on sound quality. So went back to router with lps, nice power cord straight into server (optical remains post server), much better sound quality sans FMC. This back to original configuration, always like to do A>B>A comparisons to check for confirmation bias.
IME, the two FMC, while having slightly lower noise floor, in the sense I could hear lowest level info slightly easier. it was at expense of more analytical presentation. More hifi than sense of realism I get without FMC. Transparency really took a hit with the FMC, more closed in, veiled sound quality, Decreased sound stage size, less image dimensionality, less air around performers, all contributed to less sense of performers in room.
My take is generic FMC may take more than give. Less than optimal implementation of optical for reasons given in my last post, added complexity with streaming chain may also be liability.