The Effect Gizmo is designed to run on either 12vDC or 9vAC, 550mA or more. This means regardless of the milliamp rating a typical 9vDC effects pedal power supply will NOT reliably work. The main symptom of insufficient power is that some loops may not actually activate, even though their front panel light is on. In a newer Effect Gizmo (with blue LEDs), the 1 and 9 LEDs if insufficient voltage is detected.