Is it considered a best practice to put a distortion pedal in your amp's effects loop? In general, I would say no, that's not a good idea. However, it's not necessarily going to hurt anything.
And if it won't hurt, why should we avoid it?
The details are a little bit technical, and subject to interpretation.
But for those who don't just want to take my word on it, read on for the full explanation of why you should not put a distortion pedal in an effects loop.
Read more: Best Guitar Pedals Overall
Why You Should Avoid Putting Distortion in an Effects Loop
An effects loop works by using a send and return cycle to basically place your pedals between the preamp and power amp sections of your amplifier.
This is more ideal for effects that have a wet/dry mix, like most modulation and ambient pedals. For effects that do not have a wet/dry mix, like distortion, it'll make it harder for that distortion pedal to do the job of layering your clean signal.
Again, it doesn't really hurt anything, but you gain nothing by moving your distortion pedal to your effects loop.
From our comprehensive guide on guitar pedal setup, here's a diagram that shows how this might look with a distortion pedal:
Other Gain Pedals
This is going to be true of all gain pedals. Any pedal that adjusts volume at all, perhaps with the exception of tremolo, should be left out of an effects loop. This includes the following:
All of these pedals can have an impact on your gain and are - as part of their core functionality - designed to react to volume or simply change it. Putting them in an effects loop removes their ability to interact with your preamp, meaning you lose an element of audio quality and functionality.
More Guitar Pedal Articles
The scope of this article is small, so we'll keep it short. However, we've covered a lot of other guitar pedal related topics, which we'll list here for continued reading.
To summarize, we would not recommend putting a distortion pedal in your effects loop. Instead, put it in the main line between your amp's input and your electric guitar. It'll help the distortion pedal interact better with your preamp and will sound more natural when moving from a clean to a distorted sound.
If you've got questions, we'll try and help out as much as well can.
Leave them in the comments section below.