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Anatomy of Guitar Tone: 9V vs 18V Power Supply for Overdrive Pedals

Some over drive pedals allow you to use either a 9 volt or an 18 volt power supply.

It’s said that with using an 18 volt power supply, it’s supposed to give you more headroom and a little bit more open sound and clarity. I want to try this to see if it is actually in fact true.

In this example, I’m going to use the Catalinbread Dirty Little Secret, which is kind of like a Marshall JMP style overdrive, and I’m going to use a Fulltone OCD.

What’s interesting is that in both examples, I definitely heard a difference. The most obvious difference was with the Dirty Little Secret. When I plugged in the 18 volt, it seemed like it was almost double the juice coming out of the pedal, so there was a lot more power, but it also really changed the EQ on it.

It was definitely a little bit more open. It felt less like it had a blanket on it. A little bit more presence.

A similar thing with the OCD, although I didn’t feel like there was a power fluctuation, there was a little bit more clarity and presence to it. It wasn’t so much treble as it was bitey. Just there was a little bit more clarity and presence.

[DLS 9 volt]

[DLS 18 volt]


[OCD 9 volt]

[OCD 18 volt]

Well, I don’t know about you, but I definitely heard a difference. The most obvious difference was with the Dirty Little Secret. I noticed that when I plugged in the 18 volt power supply, it almost doubled the output of the pedal.

So that was a pretty big give away. But once I settled it down and kind of put it back to a similar level that it was with the 9 volt, I did definitely notice that it felt a little more open and there was a little more clarity to the sound.


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Mark Marshall

Mark Marshall

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