Pass is solid state.
With that said, if you go solid state, the Coda S5.5 will be your best bet. Long thread elsewhere on this forum which I've linked. Many happy users including myself.
I've had decades of experience with low powered tube amplification. Lots of good suggestions above. I would say your best current bet, especially if you don't mind a pretty simple build, would be the Elekit TU-8900, also linked below.
Finally, as also suggested above, your biggest bang for the buck would be upgrading your crossovers. A suggestion is linked below.