I'm trying to figure out a way to take two separate effect lines split from an a/b/(a+b) box and mix them into a single output. I thought about the Boss LS-2, but I don't think this will work. What I would like to have is the option of running one effect line (channel a), or the other effect line (channel b) independently, or together - I think the LS-2 only gives you the option to toggle a or b, or run a+b together (that is without turning the routing selector knob, which is difficult to do when you're playing). So what I was wondering was whether or not there was a pedal-sized mixer that would allow me to use my a/b/(a+b) box to manage the effect lines, i.e., take in the two separate lines and mix them into a single line. Level controls would be cool too. I know this is confusing - I probably didn't explain this clearly - I'm confused just thinking about. Thanks for any help.