You shouldn't have a problem and will be very happy with good solid state amps driving your speakers. Check to make sure the existing pre-amp and solid state amp, output/input impedances are suitable. There are too many solid state amps out there to list that would work fine with you tube pre-amp and those speakers. make sure you audition the amps in you home with your system.
My Monolith III's sound wonderful with my Audio Research REF 3 tubed pre-amp and two Mark Levinson 23.5 amps, via a Krell KBX crossover. I had Audio Research tubed amps before, but they weren't enough for the Monoliths. Nice, but the Mark Levinsons were definitely better. Not to say that there aren't some tubed amps that are just as good or better that the Mark Levinsons. But, for the money, you really can't touch these amps. AR REF 250's would be my only amp upgrade.
enjoy
My Monolith III's sound wonderful with my Audio Research REF 3 tubed pre-amp and two Mark Levinson 23.5 amps, via a Krell KBX crossover. I had Audio Research tubed amps before, but they weren't enough for the Monoliths. Nice, but the Mark Levinsons were definitely better. Not to say that there aren't some tubed amps that are just as good or better that the Mark Levinsons. But, for the money, you really can't touch these amps. AR REF 250's would be my only amp upgrade.
enjoy