I picked up a countryman DI for a good deal on ebay. I figured it's one of those tools that I could always use in the gig box. It also happens to have a 10 mega ohm input impedance which is perfect for piezos. I hooked it up to my Fishman Sa220, which isn't a bass amp. Much to my surprise it sounded really good, and made the EQ on the SA220 easy to work with. So much so I'm considering using the setup as a monitor for my next gig with PA support. It's also silent. I know a lot of DI'S and preamps claim that, but it's difficult in the real world with bad electrical systems in bars and such. This thing is dead quiet in my practice room. If it was humming, I'd hear it standing two feet away. So I'm going to experiment a bit more with my ampeg, but so far it's impressive for a piezo buffer.