Lots of folks do this but at a minimum you have to deal with differing input sensitivities in the amps. If they don't match you'll have to figure out how to match them (easiest way is with in line attenuators). Depending on the built in crossovers in your speakers you might benefit by using an electronic crossover (the best way to solve gain problems as well) but good ones are expensive. Personally, I'd just find a powerful tube amp to control the entire spectrum. You might be surprised at what 200 tube watts (+/-) can sound like.
Has anyone mixed SS and tube amps in one system?
I am currently driving my aerial 10ts with a pair of Rotel rb980-bx amps, 125 wpc 80amps max., in a horizontal configuration. I have to say that given the low cost of these amps, the sound stage is pretty good. However, I am looking to open up the music even more. (I listen to alot of vinyl these days, mostly rock but some jazz, and I will be adding a tube phono stage soon that will help my quest for more staging.) My idea is to perhaps use these amps in monoblock (250wpc) config to drive each of the woofers and use a tube amp of about 100 to 150 wpc to drive the mids and high's. Would this pose a problem with matching amps, etc.? Should I look for another solution?