Rbstehno....yes, some of the glass cables sound better than plastic. Which glass toslink and jitter device are you using?
Macallan7....if it sounds good, leave it alone for now. Let your ears and mind get used to how it sounds and if you feel "itchy" in the future, introduce another DAC. I personally feel that most the jitter devices and "digital talk" is misleading. A good DAC can offer a big improvement, but I feel like most of it's character and presence is part of the "analog" design of the DAC. The "digital" side is important, but it doesn't seem to be the most difficult, and has very little to do with the character.
This goes against what most people think. A lot of focus is given to the "digital" aspect of the DAC, but as long as your music is uncompressed and/or lossless, and is clocked natively, everything just sings. The only DAC with jitter that really impressed me was the Altmann Attraction, but the DAC itself sounds wonderful, and when switching the settings on the Altmann, I (as well as several other listeners) could not determine what was better or not. I also really like the Naim DAC (which includes some jitter feature), but again, I like the character and presence of the DAC.
I have also heard subtle differences in different methods of getting a file to play (direct computer, Airport Express, Apple TV, Sonos, Linn DS, Naim DAC, Naim UNITI, NAS, etc....), but nothing major. I wonder how much is just in my head. I understand than some people have heard major differences in sources, and agree that some computers and streaming devices have issues. Some even go far into saying they can tell the difference in software used to rip/archive the file....I'm undecided on that claim for myself....so far.... ;)
The best thing I can recommend is keep it simple and have fun.... ;)