The Catholic tradition seems to have a bit of ambiguity about whether Tradition can include new revelation. The current position in the CCC seems to be no new public revelation. But Protestants think some developments in the tradition go beyond the bounds of interpreting and applying the Apostolic faith.
In my opinion, all forms of Christianity work the same way, despite claims to the contrary. They all start with an authoritative source, and interpret it under the guidance of the Holy Spirit. There are two differences, which aren't quite captured by "sola scriptura."
1) Protestants believe that the church can err and has erred. I think that's more important that sola scriptura, and in fact that sola scriptura follows from it. It has two consequences: (1) they are skeptical even of the early church, so rather than using both Scripture and the early church as a starting point, they use just Scripture. (2) they rejected significant parts of the tradition from which they came. But once they did that, the conservative parts are operating in the same way as Catholics and EO. The 16th Cent confessions (or for later groups, their founding beliefs) are treated as de facto inerrant, and so is the tradition coming from it. So further attempts at major change like the 16th Cent change get exactly the same reaction from conservative Protestants as the Reformation did from Catholics.
2) Mainline Protestants believe that our own tradition can err and has erred. So we are more willing to adjust beliefs and practices. We also believe that even the Biblical authors can err and have erred. That leads to treating them the same way that we would treat normal human witnesses, rather than as oracles.
He's a little unhinged.
