M233 The Micro Amp+ upgrades a classic boost circuit with EQ controls, low-noise op-amps, and true bypass switching to take this powerful boost box to the next level. This pedal can be powered by a 9-volt battery, a Dunlop ECB003 9-volt adapter, or the DC Brick™, Iso-Brick™, and Mini Iso-Brick™ power supplies (not included).