I know, it's not a bass amp, but I've heard of them being used for it. I just picked up a mid to late 70s Dual Showman Reverb in real good shape. These are 100 watt RMS all tube heads. I've hooked it to my Ampeg B25B cab with the 2-15 421A Altec speakers. Of course, it sounds sweet with a Strat, but almost as good with a Danelectro Longhorn bass with flats. A huge reverb that sounds really interesting with it full on with the Longhorn. 
