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?

I would be comfortable saying that the Aguliar doesn't add "gain" to the signal and its probably the cleanest set flat in terms of coloring the signal. I don't have much experience with the Bart pre amps (I love the pick ups but haven't tried the pre amps yet)

In the Aguilar, is both pots off flat? I know it's boost only.

On my Lakland, I can set the gain on the preamp to match the passive volume. I'm sure other Bart preamps can do that. OTOH on my 84 Tobias 5 string, if you turn all three bands down there is no output.

Short answer... it depends;)