AN OVERDRIVE PRIMER

THE OVERDRIVE GROUP

There are many kinds of overdrives...they cover all styles. If you play in one style you may just have one. Others... for example... cover bands doing a variety of styles and can use  more.

I started the list with the group that has the lightest distortion and the proceeding groups produce more.

Keep in mind there is a blur where one type of OD starts or stops. Some distortions are used as OD's .  Some Distortions are really only at their best as an OD. Yet another blur.
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I am in an original material Indie Alternative and I use them all ...In fact I have thirteen of them plus an antique type Germanium Fuzz and treble booster.
This was the preferred...overdrive of the mid 60's thru to about the mid 70's by guitarist that put the classic overdrive sound on the proverbial map.
I won't mention my Martin which has it's own very cool pedal.

TYPES

LOW GAIN OD

- this is the group of Ibanez ts808 and Klons of which there are  dozens of clones and Me-Too pedals.  They can be pushed to be fairly aggressive but what they do that others can not... is give you a crisp clean distortion that leaves the tone of the guitar going thru unaltered.

 In styles like funk where a completely clean sound has no bite and might muddy a bit they give you a nice crisp edge for  fast strumming of both open and muted chords played with a brisk rhythm.

FENDER BROWN & TWEED OD

- these are not so unlike the ts808 but are warmer and fuller and considerably more aggressive.. Great for a fuller or assertive sound to back up vocals. They give you a very sweet sound for fills. They to can be pushed but if they are they muddy up a bit.

BLUES OD

-these were derived from the sounds of the Chicago (and others) blues players from the 50's who usually used underpowered budget amps cranked up full. They can be harsh and nasty sometimes even a bit muddy if pushed... but they have incredible bite. The sound is exciting but not too full and leaves a lot of space for the band. They are especially very good for playing muted sounds. They also work great when you double up a riff with the bass player.

MODELED OD
-these are overdrives that imitate the classic distorted sounds of  amps like the Mesa Boogie MKII  a Marshall Plexi or JCM800...or a Vox AC30  Some do a stellar imitation of the distortion of the amps they are copying. Others simply give you a good impression of the sound. All are very usable.
They go medium to heavy on the distortion. 
Personally I love them. I have one for a JCM800 and another for a  Plexi and one that gives me that sweet middy sound not so unlike a Boogie. This way I can get a Brit or American sound depending on the tune.

  METAL OD
- yes... in a word Metal. All have excessive distortion are massive sounding. Playing them is the most fun you can have and still keep your clothes on.

There is the AMERICAN METAL sound-
A huge bass with screaming highs that is  scooped (or cut) in the mid range.
and...often just  a little peak in the upper mid range at 1k that gives them a singing quality to the sound.

There is the classic BRIT METAL sound-
The bass is just a bit higher then the mids...the mids are crushingly massive  with that little peak at 1k and the highs just barely peak over the mids.



 BOOSTERS &  PREAMPS
- some guitarist like to get some or all their distortion from their amp...but they can get more by pushing a booster or pedal preamp. Others use the ts808 for a booster by turning up the level/volume but backing off the gain.  Stevie Ray Vaughn never turned his off...he just backed off the volume on his Strat.  Lately the re-discovery of the use of the defunct mid 60's  Rangemaster treble booster has fostered a resurgence in clones...that keep your tone clean and natural but depend on the amp to do the work.  (check the treble booster Post)

AMP MODELING
-this is a grey area. Some pedals are a complete imitation of a specific amp and can even be recorded direct. I am sure that most players use them thru their amp first and occasionally for recording. Because many guitarist use these for OD  I thought I would include them. Many are very good and some are both great sounding  and cheap too. I do not consider them OD as such.  They are in a completely new category.

But!!! Many guitarist buy them only to set them up to use as an overdrive...so where applicable I will put them in with the Modeled OD's.

THE CHANNEL OVERDRIVE
-many of the other overdrives are used this way...but it is fast becoming the cutting edge way to work. 

One uses an amp with basically one channel. 
Back to basics...as before the 70's all amps had only one channel.
This is your clean channel. 
You choose a great overdrive to be your second channel. 
You then can add whatever other pedals you like.It has many key advantages. Your sound is mostly contained in your pedal board. You can get a great sound at any volume level. Lastly...if you have to rent...beg...borrow or steal many varied amps for the gig. It does very little to destroy the sound that you carefully put together.

CONCLUSION

... as for popularity the most popular OD's in the last 2 years are usually based on the Marshall JMC 800 or a hot rodded Plexi...I feel it is because they take screaming distortion to a level that is just short of the sound loosing its tube amp roots before turning the sound into an unidentifiable abstract tone or a Fuzz.
They are my personal favourite. I have a few.



FUZZ PEDALS AS OD

-the Fuzz has it's own post. 
Fuzz pedals have always been used as overdrives.
lately the combination of teaming a very early generation mid 60's Germanium fuzz pedal with a like wise era treble booster has been rediscovered and a variety of both fuzz and treble boosters have been cloned or modified and are rapidly becoming the first choice OD of many.
(check both the Fuzz and the Teble Booster Post's)