I never heard the PA-5, but a good friend of mine has a PA-7 driving a pair of Magneplanar 3.5R´s, and it sounds excellent.
Very underrated amps, if you ask me.
Here´s a pic I took the first time I went over to his place to listen to his system. yeah, it was covered in dust, I told my friend he should be ashamed of himself, and he was.