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Anatomy of Guitar Tone: Preamp Before Overdrive

Preamp Before Overdrive [Anatomy of Guitar Tone]
Preamp Before Overdrive [Anatomy of Guitar Tone]

Hey everyone. This is Mark Marshall with and

I was thinking a lot this week about overdrive pedals, and whether placing an EP booster before the overdrive pedals would change the character of the overdrive.

Now, what I mean is by setting up the overdrive pedals so it’s at lower gain and using the EP booster to really hit the pedal so it gets more gain, versus just cranking up the gain knob on the overdrive pedal itself.

Sometimes I noticed that when I’m using a singular overdrive pedal for having a heavier overdrive sound, it starts to get compressed as I push up the gain knob, so I’m always searching for ways to combine pedals so that the signal doesn’t get quite as compressed and saturated sounding.


In the examples you hear, I didn’t get a super heavy overdrive pedal, but I think we can still hear the differences when I A/B them.

This example, I’m using the EP booster from Xotic, and I left them both — the dip switches are in their factory position, which is 3dB boost on and the bright switch on. I was using that in front of this Effectrode Tube Drive pedal. I was using basically two different settings on it.

Now, I should note that I did swap out the top 12AX7 for a 12A7 just for a little bit lower gain, because I use it mainly as a preamp just to warm up my tone a little bit, particularly when I’m touring and I’m stuck with backline amps that may not be my choice.

I think there’s a difference to my ears when the EP booster was paired with the tube drive. It was just a little bit more open, maybe a little bit more presence, and definitely just a tad less saturation.

Now, we’re really splitting hairs here, but I really believe when you’re recording guitars and really trying to get your sounds to really gel, a lot of these small little elements and ingredients add up and they make a big difference.

So it may seem rather minuscule, but I think in the long run, all of these things really add up, and I think about them a lot when I’m recording guitars or designing a pedalboard for a gig. My pedal arrangements may change, my choices may change, depending on the dynamics of the music I’m playing and styles.

It’s good to know all of these little tricks and keep them in your back pocket for when you’re using an overdrive sound, and you just need more saturation, but you’re just feeling like it feels too small and too compressed, and you can pull this trick out and use it.

[isolated guitar, tube drive only]

[EP booster and tube drive]


Mark Marshall

Mark Marshall is a producer, songwriter, session musician and instructor based in NYC. More at