i know frank used to use an onboard parametric eq that i think also had a 20db boost. anyone know where one can be found, or schematics to build one? there was a thing out once from chandler called a Tone-X that i think did pretty much the same thing. anyone know where to get one of those?
Frank's was custom made for him. It's main purpose was to allow him dial in any particular note to grab and feedback regardless of what room he was in or where he was standing in relation to the amp.
As far as the Tone-X goes, I'm not familiar with those. Are they not made anymore? If something was once available in a store and you can't find it anymore, it could always end up Ebay at any time. I'd watch there.
The big question is...do you need one IN your guitar? Can you do just fine using it in a "regular" way? I could see why Frank wanted it...he played on large stages all over the place which presented him with a particular problem that needed solved. If you are just playing at home or in local bars, you'd be fine just using a standard one in a rack or stompbox.