MID BOOST is a midrange-frequency boost. You can use this to add fatness to your clean or overdrive tones, or even make single coil guitars sound thicker and less scooped. We particularly like MID BOOST with the overdrive mode. With the toggle switch in the UP position, MID BOOST is on. In the DOWN position, MID BOOST is off.

My self assembled OTS sounds great but I realized after tweaking that the mid boost is probably not working right.  When I toggle up, it boosts but cuts all the highs as if my guitar tone knob was all the down. 

It doesn't sound like this is right.  Any tips?  Maybe wired something backwards or shorted another thing?

Thanks_

Which model OTS? Most of these have been out for quite a while, and I've never seen any other complaints about the mid boost not working - I'd think that if this is something that just got fixed, none of them would have worked up to this point (and mine on my bluesmaster works fine).