Tube amp, more low end

I've just taken my first step into tubes, with a TAD-60. My speakers are Gallo 3.1's. I really like this amp! I can't believe how "real" the music sounds. It really is amazing. The one thing that I do feel is lacking however, is low end "slam", as well as control. I know generally speaking, this is a characteristic of tubes. But I'm wondering I there's an affordable tube amp ($1500-$2000), that will offer the magic of the TAD, but with some more low end control?

Also, the TAD is currently running el34's. Would switching to kt88's make much of a difference? If I need to spend $300 or $400 on better tubes, I'd just as soon upgrade the amp.

Than