I'm thinking of getting an A/B box for switching between my electric bass and EUB. I wish it had an internal buffer (most of my pedals are true-bypass) and a separate volume control for each input. Are there any on the market? I made a search and found only 2-channel preamps (such as Bassbone and Microbass 2) with built-in EQ, DI and some other features that I don't really need.