For some time,Triode Electronics has been offering a 30W "Universal" SE transformer that nominally has a 1250 ohm primary impedance, but can do 5k if the 16 ohm tap is used at 8 ohms. It looks like an interesting candidate for output in a 813 "Super Schade" amp I've been considering. The price is about 10 bucks more than a Hammond. Has anyone tried this one? They're on sale now.