Guitar Pedal Power Guide: Polarity, Milliamp Sizing & Isolated Bricks
Guitar effects pedals are notorious for non-standard power requirements. Connecting a standard consumer electronics adapter will usually result in dead silence or fried components. Here is what every guitarist needs to know.
9V Center-Negative (⊖)
Standardized by Boss in the 1970s, the center pin is Negative (-) and the outer barrel is Positive (+). Plugging a standard center-positive adapter will blow the pedal's protection diode.
Analog vs Digital mA
Analog overdrives (Tube Screamer, Fuzz) draw only 5–25 mA. Digital delays, reverbs, and DSP modelers (Strymon, Line 6) draw 250–500+ mA. Underpowering digital pedals causes audio glitches or boot failure.
Isolated vs Daisy Chains
Daisy chains share a common electrical ground, introducing digital high-pitched whine and 60Hz hum into high-gain pedals. True isolated power supplies eliminate ground loops entirely.
Typical Current Draws by Pedal Category
| Pedal Category | Typical Current Draw | Voltage | Example Models |
|---|---|---|---|
| Analog Overdrive / Distortion | 5 mA – 20 mA | 9V DC | Ibanez TS9, Boss DS-1, ProCo Rat |
| Analog Modulation (Chorus, Phase) | 15 mA – 50 mA | 9V DC | MXR Phase 90, Boss CE-2W |
| Digital Delay & Reverb | 150 mA – 400 mA | 9V DC | Strymon BigSky, TC Hall of Fame, Boss DD-8 |
| Multi-FX & Amp Modelers | 800 mA – 3000 mA | 9V / 12V DC | Line 6 HX Stomp, Quad Cortex, Boss GT-1000 |
Can You Run a 9V Pedal at 18V for More Headroom?
Only if explicitly rated by the manufacturer (e.g. Fulltone OCD, Catalinbread pedals). Running an analog dirt pedal at 18V increases dynamic range and clean headroom. However, connecting 18V to a standard 9V-only pedal will destroy electrolytic capacitors and op-amps. Check manufacturer documentation before testing.
Check your guitar pedal power supply match
Verify voltage, center-negative polarity, and mA draw with our instant checker.
Test 9V Pedal Match in CheckerRelated Calculators & Checkers
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