Some mention the EEvblog. I'm sorry to say, but the EEVblog with it's rambling is all nothing but plain bla bla and nothing to learn. You better not copy he's schematics if you want to build something that work. He doesn't even know how to make an emitter follower that doesn't oscillate. (For the record, it's not the op-amp that causes this circuit to oscillate. It's the emitter follower itself who's oscillating. It would even oscillate without feedback.)

If you wanne seem him going down? Check out this one.

http://www.youtube.com/watch?v=b7UQVZaqxg0

Base stopper resistors? Huh? Anyone.

And apart from that. He sounds like a cat.

Regards