Greg Fryer Treble Booster Deluxe

Well built simple Brian May signature booster. And the original unit is reasonably priced, goopless box - so you should concider getting one. Basic info from manufacturer's site:
" Powerful, rich, good treble detail"

• 35 dB gain 
• Punchy rich sound 
• Balance between fatness and treble definition
• Evokes the BM sound of mid 1970s Queen albums "Sheer Heart Attack", "A Day At The Races" and the Brian May 1980s live concert sound.

Adding volume control to the output may be worth a try... (that's 100K log pot, board output to lug 3, lug 2 is your new output and lug 1 to ground...)