I've never actually heard it before

I’ve never actually heard it before.

Question: If I add “OF” after heard, does it make any difference?
[I’ve never actually heard of it before.] and [I’ve never actually heard it before.] are different?

Thank you!!!

Yes. Just “heard” means you have heard directly. The difference is small though.

@Demolinator is correct, the difference can be slight. You give no context for this example, but let’s use this:

“There’s a rumor that somebody did something.”

  1. “I have not heard it” means I have not heard the rumor.
  2. “I have not heard of it” means, perhaps, that I have not heard about the subject of the rumor, I have not heard about somebody doing something.
    That’s almost the same thing. But on the other hand:

“I think that Beethoven’s Ninth Symphony is wonderful. Listen…”

  1. “I’ve not heard it before” means that I have not heard (listened to) that symphony before now.
  2. “I’ve not heard of it before” means that I hadn’t known about that symphony; I didn’t know of its existence.
    That’s a much bigger difference.