Amp/xover for Hartley 24 subwoofer

Hi Guys. I'm running a wall-mounted Hartley 24" woofer as a subwoofer to my Maggie 20.1's. It is powered at present by a Manley 170 watt mono tube amp, crossed over at 18db/octave at 50Hz by a Dahlquist DQ-10 crossover. My Maggies are rolled off at 6db/octave at 100Hz by a simple capacitor. I'm thinking I can do better with a solid state amp and a parametric equalizer/crossover at 24db/octave (keeping the 6db/octave for the high pass). Any ideas?