I'm not getting involved, but I don't plan to be back until Summer Project 2025 since my Summer Project 2024 has concluded. I only have energy for Summer Projects in this hobby so I'm not full-time so I'll share my alternative POV.
I think the goal here is to quell the masses to put down their pitchforks. Toslink is a nice bandage solution, but IMO not the most optimal. But to get optimal, you need Super Caps and I highly discourage anyone from implementing Super Caps because there are real risks. This is a general Audio problem not specific to just Chord.
Yes, Toslink might initially sound better but after the brain adapts over time USB optical is the only way to achieve Chord Purity IMO. It's the right fundamentally ASYNC sound implementation to pursue. But I guess if you are feeding an HMS, Toslink will just act like a dummy feeder spitting out "Square Waves" so the Toslink Receiver just needs to decipher the 1s and 0s. But you are still dealing with digital artifacts (Harmonic Distortions) from the Toslink Source. A variance I no longer consider "Pure". After the honeymoon period with Toslink, USB optical will generally smooth out the fluctuations over time to get the "Pure" Chord Sound. It will flatten the curve, so USB optical wins out in the long run after the brain adapts.
But this is like asking your CPU Designer to build you a highly-spec PC. I would not trust my CPU Designer to do so. I don't know why there is such a dependence on the DAC Designer to hold your hand. It's a daunting task for him to take on. I see so many snitch to the DAC Designer too. They can't even wipe their buts without running to the DAC Designer. You can't expect the DAC Designer to try out every possible available modern solution either, so legacy Toslink is a safe choice for the normie user in 2nd Quarter of 2024.
Over the years, I've seen comments about the Chord USB input being defective. I remained skeptical. Yes, I h8ed USB but I not going to go as far as calling it defective. It was not until I unlocked Galvanic Isolation and used a USB optical cable (Technically, it can be considered Toslink too if you narrow it down to just the internal optical wiring). I now have the best of both worlds, but in my experience both the USB and Toslink inputs are solid.
So it is a difficult balancing act. For the 90% of normies out there, Toslink should do the job. For the enthusiast / purists there is another option, but with strings attached.
I can't take a USB chain seriously also without PCI-E in the mix, that's why I would never trust my DAC Designer to architect my chain. 90%+ of his suggestions are solid, but again his specialty is DAC Designing which has nothing to do with how to put a chain together. Doesn't even know PCI-E exists.
So toslink is a safe choice as it just feeds 1s and 0s while decoupling. But I found USB optical while also decoupling is the purest way to get that Chord Sound especially with non-amplified Live Music. While I still enjoy Toslink, the fundamentally sound thing to do is to let it go. Before 2024, Toslink camp. During 2024 as the curve flattened (brain burn-in), USB optical for the long-term as it's the right thing to do but with huge strings attached. But I'm also obsessed with Soundstage Depth since that is a thing now with USB optical.
Also, for modern DACs the goal is to feed data as close the the DAC PLL as possible. With ASYNC USB, data buffers internally near the PLL. Toslink is an external complication. Your outsourcing the data instead of handling it internally.
Before I go on hiatus, shout out to romaz (Chord Legend circa 2017) for recommending the USB optical cable at the start of COVID. It changed my Chord ARC and I now understand the Chord Sound in it's purest form but only after Super Cap supply chains replenished Post-COVID.
Tuff Hobby.
