The Classic Overdrive Pedal

Overdrive remains one of the most essential tools in any musician’s kit box. The answer to the immortal question: ‘Which overdrive pedal is the best of all time?’ will differ depending on which guitarist you’re talking to. This is because no overdrive can weave its magic on its own, instead, it all happens in the delicate interplay between your amplifier and your chosen pedal – not to mention, your carefully sculpted go-to settings. The world of overdrive is filled with myths and mysterious legends about the magic ingredients involved, but we’re here to find the truth behind it all, with a little help from the stone-cold classic that is the Ibanez Tube Screamer.

The Theory Behind Overdrive & Distortion

To explain the difference between overdrive and distortion, first we need to look at a short and simple bit of the theory. Both terms come from the sound of valve amplifiers, which take an electrical signal from an electric guitar, pushes it through a preamp and power amp section before spitting it out of some speakers where it’s turned into sweetly balanced sound waves. However, the moment an amplifier is pushed to perform above its limits, those sound waves start to shorten – a phenomenon known as clipping. Initially, the clipping is even, AKA ‘soft-clipping’, but at some point, the sound waves are cut off more brutally, AKA ‘hard-clipping’. In terms of sound, soft-clipping is a light distortion (otherwise known as overdrive), while the sound of distortion is made possible by hard clipping. Put simply, overdrive begins with light distortion and distortion starts where overdrive ends.

Picture courtesy of GM Arts

What Does Overdrive Do?

The goal of any overdrive is twofold, so an overdrive pedal can be used to internally clip the sound of your guitar before sending the distorted signal to the amplifier. At the same time, overdrive pedals can be used to boost the signal of your guitar before it reaches the amplifier. As such, an overdrive pedal can be used to give an amplifier that’s already on the edge of overdrive that extra little push, resulting in that sweet and tasty drive sound we all know and love. At this point, it’s worth understanding that all this depends on the settings of both the pedal and the amplifier involved. While some pedals are designed to have a really big impact on the sound of your amp, some are specifically designed to keep the sound as transparent as possible.

The Ibanez TS808 Tube Screamer

Even after 30 years in the game, the Ibanez TS808 Tube Screamer is still the overdrive pedal that all other overdrive pedals are measured against. This stompbox was originally designed for boosting the sound of a transistor amplifier with a more organic valve-style drive, but would soon become the ideal team-mate for valve amplifiers – especially Fender models. In fact, if you were to place a vintage Tube Screamer in front of a good clean transistor amplifier, you’ll probably be disappointed by the result. In electric blues as well as heavier styles, the TS808 is often deployed as a boost pedal, with the drive pot pulled almost all the way down while the volume is opened almost all the way up.

Despite its legendary status, the TS808 is both famous and infamous these days. Infamous, because of the considerable mid-boost it can’t help applying to anything you stick through it. Amplifiers renowned for their sparkling sound and rich trebles definitely benefit from this because it helps warm up and thicken the sound by rounding off the sharper edges of the trebles. However, with Marshalls and other amplifiers with a naturally woolly sound and an already rich mid-range, it can quickly bury all of the basses and trebles. As such, modern editions of the Screamer have tried to correct this with a more expanded EQ section or a bass boost – or both.

Snake Oil

For the true gear-head, no Screamer ever sounds exactly the same as the next. As we’ve already mentioned, the job of an overdrive is to apply internal clipping (or distortion) and it does this via an electronic circuit. With a classic overdrive pedal, this circuit is made out of two little operational amplifiers, otherwise known as opamps. For any purists, the first opamp always has to have a JRC4558 chip at its heart plus a number of diodes, while the second opamp is built out of a network of capacitors and resistors.

While renowned, the JRC4558 isn’t exactly the perfect overdrive solution. The fact that the classic MXR Distortion+ uses exactly the same chip should say enough, because, while the Screamer and the Distortion+ both share the same electronic guts, they somehow sound completely different. Even the more modern Fulltone Full-Drive features a JRC4558 chip and has its own unique sound, which means that the chip isn’t everything. All of the diodes, capacitors and resistors that go into the circuit also have a big impact on the sound. It also means that, by experimenting and swapping bits out you could, in theory, build your own ideal classic overdrive pedal – just as long as you have the technical chops and some skills with a soldering iron.

It also seems that, because it is relatively easy to build your own overdrive pedal, a lot of manufacturers tend to hit users with terms like ‘silicon/germanium diodes’, ‘LED’, ‘MOSFET’ and ‘asymmetrical clipping’, which all sounds great, but if we’re being honest, the average guitarist is unlikely to have a clue what any of it means. Luckily there are people in the world like Jamie Stillman of EarthQuaker Devices fame, who, years ago when he was a poor musician, took it upon himself to fix his own drive pedal. The internal circuit turned out to be nothing too mysterious for him so he quickly started to experiment with different components and switchings and later, started building his own pedals from scratch. His creations gained a following among the local guitarists and, in 2005, EarthQuaker Devices was founded. The company has since grown into a big player on the heavily populated effect pedal scene.

Initially, EarthQuaker Devices avoided trying to make their own Tube Screamer style overdrive, mainly because of all the different camps who swore by silicon diodes or germanium diodes and so on. Eventually, they could no longer resist but, instead of making themselves choose between one or the other, they just combined all possible worlds in one innovative pedal. The result of all of this is the EarthQuaker Devices Palisades: an overdrive that allows guitarists to experiment with an array of different clipping and diode types. With the Palisades, you don’t need to know anything about soldering if you want to build your own custom two-channel overdrive – it was all laid out for you already. The model also single-handedly ended the discussion about buffered and un-buffered bypass by simply adding a mini-switch so you could just reach down and flip between the two.

Of course, for anyone who does have a little knowledge about electronics, it’s still a lot of fun to get stuck in and experiment with your own creations. But for the guitarist that’s less interested in the inner workings, the Palisades presents an opportunity to unravel the mystery that is overdrive. The only downside with Earthquaker Devices models is the lead time. Every pedal is built by hand and, like all hand-built pedals, they aren’t so easy to get hold of. Thankfully, there are more than enough classic overdrives out there that use the legendary JRC-4558 chip, from the pretty affordable Electro Harmonix East River Drive to the pretty expensive Hand-Wired Ibanez Tube Screamer. The Route 808 made by TrueTone (previously known as Visual Sound) was a great example but, unfortunately, it’s no longer in production. Then there’s the V2 Double Trouble, which gives you two JRC-4558 reinforced overdrives for the price of one.

To Chip or Not to Chip?

For browsing guitarists, it won’t be too hard to figure out which overdrive pedals feature a JRC-4558. Because this wee chip is such a legend, manufacturers take every opportunity to mention it anywhere and everywhere. Picking out the classic overdrive that best fits your vibe is a lonely task, however – only you can know which one will work out. We recommend trying out a few in your friendly neighbourhood guitar shop. Just remember, while it’s tempting to try it out with a combo like a Fender Custom Shop Stratocaster and a hand-wired VOX AC-30, it makes more sense to test out a pedal with the gear that you usually use at home or with your band.