When to Use Your Amp’s Effects Loop

by Mitch Gallagher

In my opinion, we live in the Golden Age of Guitar Gear. Yes, I know that there are certain lust-worthy vintage guitars, amps, and pedals, but the vast array of great gear available today — much of it amazingly affordable in relative terms — is unrivaled. But all that gear brings a lot of questions. Let’s focus in on just one of those questions today — but it’s one that can make a big difference in your tone: where do you place your pedals; in front of the amp or in the amp’s effects loop?

WHAT

A couple of definitions first. “In front of your amp” means connecting the pedals between your guitar and the amp’s input. Run a cable out of the guitar, to the input of the pedal(s), then come out of the pedals into the amp. This is the “old-school” way of connecting pedals, and it has served well in many situations since the late 1960s.

“In the amp’s effects loop” begs a bit more explanation. Broadly speaking, there are two sections in a guitar amplifier: First, there’s the preamp, which takes the incoming guitar signal and boosts it up — maybe to (or past) the point of distortion — and shapes the sound using tone controls. Following the preamp section we have the power amp section. This section takes the signal coming from the preamp and radically cranks it up to the level where it can drive a speaker.

But it’s the “in-between” point that we’re interested in here — the junction between the preamp and the power amp. We can break that junction and send the signal out of the preamp to be processed by effects, then bring the processed signal back in to be amplified by the power amp. (Thus the original name for an amplifier effects loop: preamp out/power amp in.) Back in the day, this resulted in some compatibility issues, since the output from the preamp can be too hot to drive many pedals. But today, most amplifier effects loops use buffering circuitry so that everything connects together happily. 

LOOPY

There are two ways that an effects loop in a guitar amp can be set up. With a series effects loop, the entire signal coming from the preamp routes out of the effects loop to be processed and is brought back in — the idea is still “preamp out/power amp in,” but usually with buffering and proper signal levels. This works great if you want to process the complete signal and/or can control the wet/dry balance of effected vs. unaffected signal inside your pedals with their built-in mix or blend controls. In most cases, this is the type of effects loop you’ll see in guitar amps.

The second approach is a parallel effects loop. In this case, the signal from the preamp is split before it continues on to the loop. One side routes straight to the power amplifier, so it remains dry, with no effects. The other side routes out of the effects loop to be processed, is brought back in, and mixes with the dry signal. This is handy when you want to blend wet and dry but you don’t have control over wet/dry mix within your pedals.

One other detail: some amplifier effects loops feature level controls or can be switched from +4 to -10 or to instrument level. This allows the loop to feed studio-quality rack gear or regular guitar pedals equally well. Generally, if you’re using rack gear, you’ll want to be at +4. if you’re using pedals, you’ll want to be at the lower setting.

CONNECTIONS

With that background information out of the way, let’s talk about where to connect your pedals. As with most discussions of guitar gear and tone, you’re going to see a lot of “it depends” sorts of comments here. That’s because there really is no right or wrong with this topic, you won’t damage any gear by hooking it up “wrong,” and you’re not going to hurt my feelings if you don’t follow the “rules.” The goal is to achieve the tone that you want. Whatever you have to do to make that tone happen is just fine.

Let’s get one thing out of the way, right away: You can connect all your pedals in front of the amp, just like Jimi did back in 1969 — even if your amp has an effects loop. No harm no foul, and no one says you have to use the loop. The “it depends” part of this is that you may or may not like how all your pedals sound when  connected in this way, depending on where you get any overdrive/gain/distortion you’re using from, pedals or the amp.

If the amp is serving as a clean, neutral platform, and you’re generating any overdrive/distortion/fuzz using pedals, this will work just fine. In this situation, conventional wisdom says to route out of your guitar, into your gain/dirt pedals, then into time-based effects (delay and reverb), then into the clean input of the amp. 

Modulation (chorus, flange, phase, rotary speaker, et al) and other effects (filters, EQ, pitch shift, et al) can go either before the dirt pedals for a more washed out sound or after the dirt pedals for a more intense effect. Typically you would not run your time-based effects in front of the dirt pedals, because the distortion tends to compress incoming signals, changing the relationship of the delay to the dry signal and making things messy. But it depends! Some players want that kind of sound. Reverb is very rarely used before dirt pedals; it just doesn’t distort very well.

We can take this same approach — but integrate the effects loop into it — if you’re using the preamp of your amplifier to generate your gain/distortion/overdrive/fuzz. Put any boosts or overdrives in front of the amp to hit the input harder. But put time-based delays and reverbs into the loop to process the distorted sound. This will give a cleaner response and more defined sound from delays. As before, reverb tends to work best at the end of the chain — in this case, “end of the chain” meaning last in the effects loop — but of course, it depends… Modulation and other effects can go either in front of the amp or in the effects loop depending on the result that you want from them.

EXCEPTIONS

There are a few types of pedals that work well either in front of the amp or in the effects loop…depending on what you want. We already mentioned modulation effects. Another example is a volume pedal. You can place it at the front of your chain, to control the volume from the guitar feeding into your pedals and amp. You can place it last in the chain in front of your amp, as sort of a master volume control for the effects chain. Or, you can place it in the effects loop as an overall master volume control for the whole rig, before or after delays and reverb — if it’s in front of delays, you can use it to create “swell” and “ambient” effects. it depends on how you want to use the volume pedal.

SUM IT UP

Here are basic guidelines (not rules) that will help you get started with figuring out how to route your pedals. Note #1: in all of these, modulation and other pedals (filters, pitch shift, EQ, etc.) can be placed in several different locations, depending on the result you want. Note #2: some wah pedals prefer to be the first pedal in the chain, before any buffers.

Clean or dirty amp with no effects loop, or clean amp with gain from distortion/overdrive/fuzz pedals:

Guitar

buffer, tuner, wah & compressor, if used

modulation & other pedals (option 1)

dirt pedals

modulation & other pedals (option 2)

delay

modulation & other pedals (option 3)

reverb

Amp Input

Clean amp with effects loop, with gain from distortion/overdrive/fuzz pedals:

Guitar

buffer, tuner, wah & compressor, if used

modulation & other pedals (option 1)

dirt pedals

modulation & other pedals (option 2)

Amp Input

Amp Effects Send

modulation & other pedals (option 3)

delay

modulation & other pedals (option 4)

reverb

Amp Effects Return

Dirty amp with effects loop, with gain from amplifier’s preamp:

Guitar

buffer, tuner, wah & compressor, if used

modulation & other pedals (option 1)

Amp Input

Amp Effects Send

modulation & other pedals (option 2)

delay

modulation other pedals (option 3)

reverb

Amp Effects Return

EVEN SUMMIER

To sum it up even more, put your tuner, wah, and gain pedals in front of the amp. (Optionally modulation and other pedals too, if you like that sound.) Put your time-based effects (delay and reverb) in the effects loop. (Optionally modulation and other pedals, too, if you like that sound.) 

THE BOTTOM LINE

Should you route your pedals in front of the amp or in the effects loop? Sure! You should! Both can work very well, depending on the sound you want. There is “Conventional Wisdom,” but use that as a starting point, not as a rule inscribed in rock. Experiment! You won’t hurt anything, and you may find combinations of pedals and routings that you like. 

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Mitch Gallagher, is one of the leading music/pro audio/audio recording authorities in the world. The former senior technical editor of Keyboard magazine and former editor-in-chief of EQ magazine, Gallagher has published thousands of articles, is the author of seven books and one instructional DVD, and appears in well over 500 videos on YouTube. He teaches audio recording and music business at Purdue University/Indiana University, and has appeared at festivals, conventions, and conferences around the world.