Felt the same about the Rumble 100- mostly trying in stores, so take that FWIW. Could not seem to get much definition at "lower" volumes. That said, I once tried a Sansamp BDDI V2 into the effects return of a Rumble 100, and wow- that added a ton of definition, bypassing the front end altogether. That said, I really like that Ampeg RB108- as you mentioned, its very tight, quick, and enjoyable to play for home practice. The RB-112 is pretty solid and can certainly get louder with a drummer, etc., but there is something about the 108 and the RB-110 (my current home combo) that I really enjoy- easy to dial-in, warm, and punchy without "tearing down the walls".