Fulltone FPS-2 Adaptor
The problem with 99.9% of all wall-wart adapters is that they are NOT regulated, some straying up to 13 volts or so, causing Hum and horrible tone. Enter the Fulltone FPS-2 (200 ma.) Regulated adapter....dead quiet, and exactly 9 volts no matter what your wall AC is putting out. This has the standard 2.1mm x 5.5mm end with a positive.
FPS-2 (positive center pin) ONLY for use with 69, SoulBender & OctaFuzz. For all others, select the FPS-1.