Pair of 10K:8 49% nickel output transformers to get 7W out of an 841 @ 35ma. Inductance is 150hy's with a +-5ma window and the top end is flat to 50K before the squirrels show up.
These 4 are for the 801 running at 25ma and the same +- 5ma window. One pair is a simple 4:1 stepdown and the other is the first (gasp) phase splitter I will take credit for.
This is a fun topic and I will leave you with a sense of scale.