Yes - I've had MAXX's die on me as well...likely for a similiar reason: wallwart 9V supplies. I wonder if 9V batteries are culprits (as much) here?
Some 9V adapters put out a bit over the top as well..plus, maybe MAXXs aren't designed for wallwart levels (?) I've gauged my RS 9V filtered adapter (lg bodied) @ an actual 11-12 V when going into my breadboard supply!
I'd try this: put a 100 or so ohm resistor pre MAXX 1044 - that should bring the voltage down just a bit. Then you might derive a bipolar supply w'out killing the nice MAXX. I'd think 8.5 V wouldn't really harm your headroom/pedal fidelity - or would it?
@ any rate tho' I plan to upgrade as per the suggestion for the LT1054 & the TC______ unit.
Biploar supplies are a must when you get into Boscorelli-land.....or , you have some circuits on your custom PT that need more headroom ; phaser-vibe-complex modulation clones,etc