Topband: Binocular cores for 2N5109 preamp

[Steve Flood]

Having built a few of the 2N5109 push-pull preamps, I'm now wondering how to use the BN-73-202 binocular core for the transformers rather than the 43 toroids.  It appears that Tom W8JI uses these in a preamp photo on his website, and I vaguely remember another post or website that did so. 

The 4:1 Z ratio on the input and output appears to be an easy 2 turns/4 turns, but when I introduce the center-tap for balance, the inductance changes.

The feedback transformers look like a straight-forward 2turns/9turns without concern for balanced/unbalanced.

Steve, KK7UV