I like the 12B4 a lot. It does suprisingly well with the Pi Two towers and Heresy's alike. Not exceptionally loud through either, but loud enough for 99% of my listening. I'd really like to hear what it could do with some high sensitivity speakers like your K-horns. It's got remarkable bass for what it is. My Seduction is not happy being mated to the 12B4, unfortunately. I think a line stage between the Seduction and 12B4 would fix that. It seems like it just needs a little boost to get it there. I wish I had heard your 12B4 through your K-horns last year.