I have a question about Aguilar and Bartolini preamps. Even when they are set flat, do they add gain? By that I mean, if I ran the pickups passive, would they have the same amount of output as when I ran them through the OBP-1, NTBT, etc.? Is there an inherent amount of gain associated with connecting an Aguilar of Bart pre? I think I heard that the Aguilar is supposed to not have any gain when set flat. Is this correct? Also, Barts have a gain trim pot. Does this pot boost gain, as well as reduce it?