Hello. I have been following this interesting thread, and I have to admit that this amplifier has amazed me.
The output transformer solution is wonderful, 2 transformers with paralelled secondary windings, overcoming the push-pull known problem described by Manfred Mornhinweg (ludens.cl).
However, I have seen a picture of the PA-1000 with a different transformer, one with a single ferrite bead and some sort of flexible copper tape as primary. Which transformer is the PA-1000 using at present , the parallel secondary with 4 ferrite beads or the single bead with copper tape primary winding ?
My personal opinion is that the copper tubing primary winding provides better coupling than a copper tape.
![Image](http://www.oh3ac.fi/kuvat12/juma10.JPG)
73 DE LU6PSG