I am hearing so much with this combination. I just installed a Virtual Dynamics Master digital cable between those components and I am hearing so much more than I have ever before, even with the Amphenol glass.
I am learning that it is more than just 1's and 0's entering the DAC. Even though I don't exactly understand how or why the sound is different, I am pretty sure that jitter has to be the root cause of the difference.
Kijanki came to my home and explained slew rise times to me. I am a ex-digital technician and I had always worked primarily with clocked circuits. The signal from my Teac to the Valab coming through either glass or copper is asynchronous. If I understand correctly, the rise time on the toslink is pretty slow. Also any jitter in the Teac can bleed out on the rising edge of the low to high transition and enough noise on that part of the signal could possible be enough to trigger a false "1".
Any further comments on my description is very welcome... I think I am beginning to understand this a little bit better.