What makes the biggest difference in sound quality?

1. Quality of Recording
2. Overall placement, rack & cable management.

Assuming that folks are happy with their gear, they experiment with cables. Most often the result is a mishmash of kit cross talking affecting each other.

Ted's products are innovative, and almost always improve the sound. (tried with my Devialet/Boenicke combo), but are very awkward to manage.

As most of the competition, they are contributing to the mess. Improving on ergonomics is the next step.

Run an A to B to C comparison of 3 sources on my integrated / DAC Devialet 250.

1. mac mini + Lifatec Glass Toslink
2. mac mini + Intona USB Isolator + Oyaide Continental 5S USB cable
3. Project CD Box RS2 T + Kimber Kable KCAG Coax

The test involved instant switching between the 3 systems, playing for 2 mins each for maybe an hour. Same song s running on all 3 sources.

System 3 edged slightly, with system 1 (optical) second, but the differences were very subtle. To the extend I could hardly remember them had I played the systems each on a different date.

I suspect most quality DAC makers have managed to isolate the digital input from any artefacts that may come along, to such an extend that interconnects have a much lesser impact than say power input and speaker cables.