Wow!
You are correct, they were the F’s. I wonder where I came up with 7? I built a couple of Halfler DH 220’s bridged and their preamp in 1980 and in 82-2(?) I built the 400. The bridged Halfers listed more watts, but the Dynaco made the Ohms sing. As I said earlier, I gonna have to pop the top and check most of the caps. I wonder if there’s update videos on YouTube?
JD