No buffer needed between the power amp and the preamp (Bluesbreaker). That said, I've never used a BB as a preamp. You won't know if you like it till you try it. My guess, you won't have enough tonal control. You like the sound of them which is great, but you don't send it into a flat eq'd amplifier - you send it to a guitar amp. Even when you set a guitar amp eq to look flat, it has a large mid cut and sometimes other shaping.