"do you really need off-ramp with overdrive?
i think overdrive already has an off-ramp quality(if not better) usb converter built in."
You do not need an Off-Ramp with the Overdrive.
In the past, in order to get the best possible sound quality, this was necessary because the best clock, the Ultraclock, would not fit inside the Overdrive.
Now, the Superclock and Ultraclock have been replaced with our own dual Turboclock, which fits inside the Overdrive.
"Profesional reviewers are not very helpful either because they have a tendency to declare every single DAC over 5K "the best digital they ever heard" as well."
You can certainly do your own shootout with whatever DAC you can get. I have a demo available for this. There have been some direct shootouts by Pro reviewers however, such as the Dagogo review, which compares it to Berkeley, Weiss 202 and dCS Debussey.
Steve N.
Empirical Audio