While poking around YouTube I discovered this guy Christopher Thomson, an impressionist who, to my ears anyway, does a spot-on impression of Patrick Troughton's Second Doctor.
This one is my favorite (and the main reason I'm posting this), it's a brief meeting between Two and Twelve, with Thomsom performing both. His Capaldi can use a little work, but his Troughton is marvelous.
Two: It's like looking into a mirror. A rather scary mirror.
Twelve: Watch it!

Here he delivers the Pandorica speech as Troughton.
And here he performs the Curator lines from Day of the Doctor as Troughton.
Big Finish needs to hire this guy.
This one is my favorite (and the main reason I'm posting this), it's a brief meeting between Two and Twelve, with Thomsom performing both. His Capaldi can use a little work, but his Troughton is marvelous.
Two: It's like looking into a mirror. A rather scary mirror.
Twelve: Watch it!

Here he delivers the Pandorica speech as Troughton.
And here he performs the Curator lines from Day of the Doctor as Troughton.
Big Finish needs to hire this guy.