Distortion Pedals
The Most Prolific
Category of Pedal
If you are shopping for an array of pedals you will quickly find that distortion/overdrive/fuzz pedals outnumber every other category of pedals by a wide margin. I'm not certain exactly why that is the case but I suspect that it's because the subject of distortion is in itself a culture with its own lore, even its own mythology. A savvy manufacturer stands to profit greatly by catering to every faction with a product that appeals to its own tastes.
The Roots of Distortion
Any time an amplifier outputs something different than a louder version of the signal that is fed into it there is a measure of distortion at work. In the real world, all amplifiers distort slightly all of the time, but unless they are turned up a bit, the amount of distortion is minimal and only serves to add a bit of warmth to the sound. Amplifiers that distort very, very little tend to sound sterile, even harsh. I once had a solid state amp that was exceptionally clean but it was not very good sounding. I always fought ice-pick highs in any live performance situation. On the other hand it was dead reliable and would amplify to its full potential cleanly. The problem is; hardly anyone wants to sound like that.
When guitar amps first became readily available in the post WW II they tended to be fairly small. In many cases these were single-ended Class A amps that were not all that efficient and amplifiers in the 10 watt range were the rule of the day. In a living room they were clean but even a small gig would come close to the limits of the amp. Blues musicians entering the world of electric guitar found themselves playing with the natural distortion of these little amps once they turned up . . . and they quickly learned to exploit the sound, not to mention the sustain that came with it.
The British Blues revival of the early '60s brought the intentional use of distortion to a new level. When Eric Clapton recorded with John Mayall he used a Marshall amp of 30 watts turned up about as far as it would go. The result was a sound that has set a standard for electric Blues artists ever since.
Up to this point the distortion we've discussed has been the natural result of turning an amplifier up beyond the point that it can stay clean. There is, however, a problem with this method, it gets loud very quickly. When Rock 'n' Roll began to be performed in huge venues, distortion was never a problem, but as the big name acts were forced to use larger amps in order to play large venues it became impossible to produce the same sound in smaller venues unless they had a separate set of amps just for smaller jobs. Aspiring artists that bought the amps they saw their heroes use found that they couldn't get the same sound as their heroes. A Marshall stack turned up to the point of distortion would rattle the windows of a suburban bedroom and probably end up with a visit from the local Police.
In the '60s various effects pedals became popular using solid state technology. Distortion pedals were popular both with big name acts and with those that wanted to emulate them. While the quality of the distortion was somewhat different from a turned up amplifier the consistency was much greater. At any volume level distortion was available with the click of a footswitch.
Fuzz vs. Distortion vs. Overdrive
One of the first things you notice as you approach this subject is that there are three major divisions within the distortion pedal world. The first kind of distortion producing effect I ever heard of was a Fuzz pedal. Some people still refer to all distortion devices as Fuzz pedals but these day the term usually refers to the most aggressive of these devices.
If you think of the signal coming from a guitar as a sine wave of the fundamental frequency, distortion would be variations in that sine wave. A sine wave is the natural result of AC generation and a guitar pickup is a simple AC generator. Another way of having current that varies at a certain frequency would be a square wave. A square wave could be described as switched DC. Instead of the graceful arc of a sine wave a square wave is either full on or full off. Instead of a musical tone the sound of an amplified square wave would be harsh, more of a buzz than a steady tone. Many early Fuzz pedals altered the guitar signal to make it very harsh, much more like a square wave than a sine wave. The graceful peaks of the sine wave were clipped off and replaced with a flat topped form. With one of these pedals a flame-top Les Paul could sound like a chainsaw. There were, of course, degrees to all of this and less extreme settings were possible as well. While no standard definition exists to my knowledge when I hear the term "fuzz pedal" this is what I think of.
Overdrive pedals tend to be at the opposite extreme of the continuum. Most overdrive pedals are based upon modifying the sine wave in a more subtle manor, preserving, at least to some degree, the graceful nature of the sine wave but modifying it to produce a sound similar to an amp working hard for its keep. Most overdrive pedals use an asymmetric waveform to accomplish their task with the result that the sound tends to be complex and interesting. Such an approach tends to be touch sensitive and more like playing an amp on the edge of breakup. This sort of sound is popular for songs that are short of "hard rock" but still need an edge that a clean guitar doesn't provide.
Distortion pedals split the difference between all out fuzz and an overdrive pedal. Once again, there are no standard definitions to categorize these pedals, what one manufacturer calls a distortion pedal may be called an overdrive pedal by another manufacturer.
So What Do You Need?
The answer to this is dependant upon what sort of music you intend to play and what sort of amp through which you are playing. As an example, one of my favorite amps is my Fender Deluxe Reverb and it's natural sound has a lot of character. For many situations I don't need anything whatsoever to add character to the sound of this amp with any of my guitars. I use two different overdrive pedals and with the Deluxe even subtle use yields great results.
The two overdrive pedals I use are a Boss SD-1 Super Overdrive and, ironically enough, a Boss FDR-1 Deluxe Reverb pedal. The FDR-1 is setup for subtle overdrive, just a hint of an edge to the sound, while I setup the SD-1 for more gain with the tone control turned fairly high to emphasize upper harmonics. The FDR-1 pedal is actually a modeling pedal that creates it's distortion with a digital model instead of by overloading the circuitry of the pedal. The SD-1 is one of the least expensive pedals in the Boss lineup but in my opinion it is one of the best sounding pedals on the market. The controls are truly effective and you can get a great variety of sound by using the full range of all three controls.
I mention these pedals not to promote the pedals as much as to demonstrate how I use these pedals and to explain why I chose them. The point is that each pedal has a task for which it is optimized. The FDR-1 provides a predictable level of overdriven sound and makes its contribution reliably. The SD-1, in contrast, is extremely touch sensitive and even at high gain settings can go from fundamentally clean to profoundly overdriven depending upon how hard it's being pushed by the guitar.
With just these two pedals I can get any overdriven sound I need. If I played heavy metal I might need something more extreme but for Classic Rock and Blues this works well. None of this would work if the default sound of the guitar and the amplifier were not good to start with.
I use the same setup with my Twin reverb and it works quite well. The biggest difference is that the Twin doesn't display nearly as much character as the Deluxe at lower volumes. It tends to be fairly predictable and exceptionally clean. It is all but impossible to push into natural overdrive at any comfortable volume. The voicing is similar to the Deluxe, both amps are based upon the same basic circuit design. For this reason it's no surprise that both of them respond similarly to overdrive pedals.
Perhaps the biggest surprise is the effect it has on my third tube amp, a Fender Pro Junior. This amp definitely has plenty of Fender DNA influencing its sound but it's more of a distant cousin as compared to the sibling relationship between the Deluxe and the Twin. The Pro Jr. breaks up naturally at fairly low volumes without a pedal and the effect of the two overdrive pedals on this was quite different from what it was on the two Blackface amps. The SD-1 pushed it into serious breakup complete with incredible levels of sustain. What was most surprising was the effect that the FDR-1 had. Instead of pushing the amp into heavy breakup it has the effect of fortifying the clean sound of the amp. The amp stays on the edge of breakup but sounds stronger. My conclusion is that the front end of the Pro Jr. is more susceptible to being pushed into overdrive. The SD-1 boosts the level of the signal and the amp responds by breaking up. The FDR-1 creates it's effect by digital modeling and doesn't necessarily boost the signal level so the amp stays clean and only reflects the changes created within the pedal.
In my opinion the best way to approach overdrive and/or distortion pedals is to have a task in mind and find a pedal to fulfill that task. If there's another task it may be legitimate to assign another pedal to that task so that you can switch at will without having to change any settings on the pedals themselves. In some cases this may result in you having more than one copy of the same pedal simply setup differently. As an example, an SD-1 set for high level and low gain might be a great clean boost with some tone shaping while another SD-1 set for low level and high gain would provide some breakup. If both pedals were used together the result would be even more breakup and sustain. Two pedals, three sounds available just by selecting the right settings and using the footswitches.
Ultimately the overdrive/distortion pedals you choose will come down to a matter of taste and finding something that compliments both your music and your other gear. Many music stores have displays that allow you to sample a variety of pedals in a pre-arranged pedal-board. A little time spent with one of these devices will narrow your choices quickly as you eliminate the pedals you are unlikely to ever use and focus on those that suit your sonic goal. I would suggest that, if practical, you make your choices over the course of at least two visits, one to narrow the field and the second to re-compare the pedals that suit your tastes and make a final selection. No matter which pedal you select you can be sure that the manufacturers of these pedals will be burning the midnight oil to come up with even more offerings to fit the ever changing tastes of the guitar community in its collective quest for the ultimate ovredriven sound.
