Advice needed - New Frontier

My McIntosh MA6500 integrated amp's controls are fritzing/ buttons not working unless power off and on the system.  I'm thinking maybe instead of repairing I add a McIntosh C22 tube preamp and just use the MA6500 as the amp. Can I expect a noticeable sound quality bump?  I could also go solid state with a Mc C49 preamp, or just replace the whole think with a BAT tube integrated, which would cost $10k instead of $5k :(.

FYI speakers are B&W CM10s, DAC is Chord Qutest, and cables/ interconnects are Nordost AX Angels.