Ive read references to modifying PP OTs, adding a mysterious “gap” (mysterious to me at least) for SE use. What does that mean?
Probably this: process of adding a gap means carefully unstacking an interleaved PP transformer, restacking the E’s and I’s into non-interleaved chunks and reinserting the bobbin with a spacer. This gets you a transformer that has a lower primary inductance, but that won’t saturate as easily. It’s probably not what you would originally have designed for any given SE circuit, as the primary inductance is now lower, but it might work. And it REALLY appeals to the home-handyman tube hacker crafstman instinct.
