Effects Loop / (FX Loop)
Not all guitar pedals must be connected to the front end of an amplifier. Because stompboxes may be plugged into an amp's effects loop. This is a critical function that practically any serious pedal user would expect from an amplifier, as well as another attribute that distinguishes a great pedal platform amp.
If you're not familiar with an effects loop, it's essentially an input and output section (usually located at the back of an amp's chassis) that allows you to route pedals between an amplifier's preamp and power amp sections. A preamp is responsible for giving a guitar amp its voice, whereas a power amp is in charge of amplifying sound and delivering it through a speaker.
But which pedals are employed in the effects loop of an amplifier? Most guitarists will choose to route their modulation and ambient pedals through an effects loop. Chorus, flanger, phaser, reverb, and delay pedals, in other words. Because these stompboxes are positioned after the amp's preamp stage, routing them through an effects loop produces a more realistic sound. Using effects after the preamp will not significantly alter the structure of your basic tone because the preamp will still be one of the initial parts in your signal chain.