Hi
Lundahl IT´s and OPT´s, DIY:ed power transformers, Hammond chokes.
I´ve ordered a pair of LL1688 OPT´s, it´s a new model intended for 845 amps. I ordered mine with a slightly bigger airgap to allow 80mA instead of the original 70.
IT´s are LL1671/50mA driven by 6C19´s