Effects pedals are small boxes filled with electronics that manipulate the sound signal running through them. Usually they are set on the floor and have a footswitch, or pedal, to engage/disengage the effect so you can keep playing with your hands.
Depending on the type of effect, pedals have a number of knobs and switches that allow you to alter an effect’s parameters to the desired sound you want.
We can divide effects pedals into two categories: multi-effects pedals and dedicated effects pedals...
A multi-effects pedal is a single unit capable of many different types of effects. It used to be that the more effects packed into a single unit, the poorer the quality of each effect. This is improving as technology improves and becomes cheaper. But, I still think it’s somewhat true.
A multi-effects pedal is a great introduction to effects. You can learn what each one does, how to adjust the effects settings, and whether you will really use certain effects much.
Dedicated Effect Pedals
A dedicated effect pedal means it only produces one type of effect. If you know for sure you want to use a particular effect often, I recommend a dedicated effect pedal. If something was built to do one specific job, it probably does it pretty well.
If you plan on using several effects often, you can chain several dedicated effect pedals together with no problem. Just as with bass amps, anytime you go modular you have many more options when upgrading.