Of course it can be done - I am running this type of set-up right now - what makes you question it's feasability? Although the reverse set-up seems to be more common, you're actually more likely to run into a less-than-optimal impedance match running a tube preamp (which will usually have a higher output impedance than a SS one) into a SS power amp (which tend to have lower input impedances than most tube amps). Some such combo's could lead to reduced bass response, but as a practical matter, you're usually not going to run into a problem either way. As for whether it makes sense, that depends what you're after, sonically; for me, the jury is still out on whether or not I'll be happy not having tubes in my preamp in the long run. It's been a trade-off with pluses and minuses.