Curious if you could add a vintage tone control to an Aguilar OPB3 preamp? I've searched through some threads, but people seem to be talking about a tone control that works in passive mode only, another mode that has to also be wired in/modded. I'm very much a noob on this subject but essentially want to add my favorite feature of Roger's pre, the VTC, to an MTD US 6String with an Aguilar OPB3. Thing is, I could've sworn that I read of someone doing this already. If you're out there buddy, swoop on in and school me.