Characteristics of HP-IL Transformers?

[Hans Brueggemann]

haha, good catch, martin! they are as symmetric as i can measure them with my RLC meter. note that L = n^2 x AL. hence, a center-tapped winding with pins 1,2,3 and pin 2 being the center tap shows
inductance between 1-2 = L, but
inductance between 1-3 = 4 x L.

btw, according to my scientific findings (i.e., guesstimate the number of turns on the highest inductance...), toroid cores with AL >= 6000 nH will do the trick. will be trying to dig up a useful core later.