What broke. Is it a one time issue or a repeatable issue. It is a nice little amp, a bit on the warm side of neutral, for a $400 investment, but not so much if you expect future regular failure. It is an old amp, i.e. probably over 15 years but shit happens with any amp of any age.
Personally I would shop for a good quality used SS amp, if you are not adverse to their tonal qualities, with high current, to drive those speakers.
If you must have tubes be careful, high(er) power tube amps are not cheap, even used, and when so not necessarily too reliable. No free lunch there. If you have been happy with the 40wts from the SFS you might consider looking into some of the new(er) tube amps currently available in that range. Even some of the integrated ones which get some high marks.