Guitar Gear

Overdrive Creates Distortion

Overdrive is the process of overloading a device and the end result – what you hear – is distortion. Here are the fundamental ways distortion is created.

As I like to put it: overdrive is a verb, distortion is a noun.

As you can see above, there are different ways to overdrive. But in the end, all overdrive methods produce a distorted signal. Yes, each kind of distortion sounds different, but that is all dependent on where the distortion is occurring. As the illustration above shows, distortion could be only happening in the amp (booster pedal or guitar volume). It could be happening in the pedal (overdrive and distortion). It could be happening in both pedal and amp.

A Quick Word on Tube Amps with Respect to Distortion

I have to make a bit of a clarification on where the distortion happens when it comes to tube amps. For those with tube amps, some come with a master volume, while others do not, and the distortion characteristics are different depending on the type of tube amp.

With amps that don’t have a master volume, typically the full power of the preamp section goes directly to the power amp; they interact with each other directly. At high enough gain what you’ll typically get is a combination of power tube distortion and preamp distortion. This produces a fairly warm, overdriven sound. As a result, getting just moderate amounts of break-up can make your ears bleed. It’s VERY loud.

For amps with a master volume, as it was explained to me, the master volume acts as a floodgate, controlling the amount of power that will go from the preamp into the power section. In this case, distortion will come primarily from the preamp tubes. This kind of distortion tends to be a bit more “fizzy,” square-wave kind of distortion. The advantage here is that you can control your output volume much better, but unless you open up the master volume, you won’t get that power tube distortion.

And one more note with respect to master volume: Some amps, no matter how much you turn up the master volume will never saturate the power tubes. I’ve heard that Mesa amps are set up this way. Almost all the distortion comes from the preamp. That’s not a bad thing. Mesa amps always sound BIG.

What About Speaker Distortion?

Just like overloading a device (tube, etc.), a speaker can also distort if the power thrown at it is greater than its capacity to play cleanly. I didn’t originally include this in the figure above because usually, the focus of overdriving and distortion tends to be on what you put in front of the amp and at the amp itself.

With speaker distortion, the speaker goes “out of round” and produces a distorted sound. Usually, it takes A LOT of power to make this happen – read: it’s loud. And with some speakers, it may not sound very good, as speakers are not all made the same.

Speaker distortion tends to be harsh, so that sound alone may not be at all pleasing to the ears. However, it is generally accepted that as an added dimension to an already distorted signal, it can provide some real magic.

With the speakers I use (Jensen Jet Falcon and Jensen Jet Electric Lightning), the speaker distortion presents itself as a high-frequency component to my sound. It’s barely perceptible, but I know it’s happening because I don’t hear it at lower volumes. I measured the output volume threshold when this happens, and my amp has to be producing at least 95dB of volume before it comes on. But when it does, WOW! It adds yet another dimension to my tone.

And as I mentioned above, not all speakers are equally built. Size, sensitivity, and even the cabinet can affect how and if a speaker will distort. So you will have to play around with different speaker configurations.

This is just some starter information. How you achieve the distortion you want to hear takes a lot of experimentation. But that’s where it gets fun! But buyer beware: There’s a literal, monetary cost to experimentation, so as I always say, take your time and evaluate as much as you can yourself without paying for it. For sure, gather opinions, but avoid getting something purely on someone else’s recommendation. In other words, verify, verify, verify…