Signal Chain : A Look at Effects Routing (Part 1)

By Chris Liepe Published on Feb 2nd, 2011

Even if you're just starting out, you probably own or have access to some effects pedals, a guitar amp and/or a multi-effects unit. As your collection grows, so might your confusion. You may notice that your sound gets muddier instead of 'cooler.' You may buy something because you heard it on a recording you liked and then wondered why it sounds nothing like what you initially liked. You might spend more money than you need to trying to "get the sound" when you may already have all you need in an old box in your closet.

One of those things that is never really "taught" is how to place effects in your signal chain so that you'll get the most out of them. While multi-effects generally do this for you (sometimes poorly), and offer cryptic manuals detailing how they have decided your effects will be routed, I have yet to purchase a standalone pedal that includes literature telling me where to put it in the effects chain for optimum use... and why!

In Part 1 of this series we're going to look at different amp configurations, their pros and cons and talk briefly about general pedal placement. In "Part 2" we're going to look at individual FX placement and alternative ideas to get some cool, unconventional sounds.

3 Types of Amps

Most amps on the market today deal with effects routing in one of 3 ways: serial, parallel, or input only (no effects loop). Each one of these types of situations can affect the optimal settings used on certain pedals and their placement.

Serial FX Loop

This is the most common for middle of the road amps. With this setup, there is an effects send (out) and an effects return (in). When you stick a plug in to the "send" you are completely interrupting the signal flow. The "send" would then go to your pedal(s) and then the OUT from your last pedal would go in to the "return" which returns the signal to the amp.

Effects Routing

With this setup, you are blending your amp sound with each effect in the chain, so your mix knobs on your effects control how much of your original sound makes it out the other end. This can be a cool way to work, but it means that your tone gets smashed through every little box you put in it's way. If you're using good quality effects, you really don't have much to worry about, but if you have a tendency to use a ton of pedals in your loop or you've got some old, dirty pedals, some low batteries or questionable cables you can really do a number on your tone. There are pedals you can purchase to correct for this type of issue, but I like to limit my serial FX loops to about 6 good quality, fully powered pedals. It seems like there is no noticeable deterioration in tone and I can still get what I need to out of my effects.

Some amps call the effects send a "preamp out" and the effects return a "power amp in." These terms are interchangeable for the most part but suggest some interesting possibilities.

Let's say you have a combo amp with a serial FX loop. It’s a low wattage amp and you need more power. You can go out of the FX send (preamp out) and go in to a more powerful power amp... say the FX return (power amp in) of large tube amp. Remember that there will be no sound coming out of your combo amp because your effects send completely interrupts the signal, but you might get some cool sounds mixing preamps and power amps from different amps. If you experiment with this, be sure to consult your owner’s manuals and take note of any minimum load requirements for speaker outs if you are using a standalone amp head.

Most modeling boxes such as the Line 6 Pod line, Digitech RP series, Boss GTx stuff sound and feel better (when using all of their modeling technology) going directly in to the effects return of an amp rather than going in to the guitar amp's "input." This is because the pedal board/modeling box already has a preamp built in to it. Sometimes, when you plug a preamp in to another preamp, there is a muddiness or dulling of the sound that occurs. If you do this, make sure the speaker emulation on the FX box is turned off and you'll be good to go. It also works best if your amp has a master volume control. If there is no master volume, you have no way of controlling your volume except on your FX unit output.

Parallel FX Loop

This type of loop allows your amp signal to pass 'untouched' from the guitar through the amp to the speaker and then simultaneously add the FX signal to the original tone rather than giving that responsibility to each individual pedal. Here's how this looks:

Effects Loops

If your amp has an FX level control on it somewhere, it probably has a parallel FX loop. This setup is great because it allows all the original tone through no matter what, and then you get to choose how much of the 'wet' sound you want to include in your signal with your amp. In many cases, this is cleaner, and you don't have as much of an issue with one 'bad' pedal sucking the tone out of your amp. Because you're allowing the amp signal to pass PLUS your FX signal, you'll want to make sure that your pedal's "mix level" controls are set to 100% so that you aren't ending up with a partially dry tone in addition to your completely dry tone (this can sound quite weird with certain effects).

This setup does have its drawbacks. Certain effects such as tremolos don't function well in this environment because they need control over the whole signal to generate their desired effect. For example, if you want that "ON/OFF" square pulsing effect out of your tremolo, you can't add that to a dry, raw amp signal or you won't ever have any "OFF." You'll have amp sound, PLUS the tremolo ON/OFF which will lead to a "more or less" effect... not what you intended. Jet flangers, harmonizers, rotary speaker simulations and certain other chorus effects are among those that also don't do too well with parallel setups. Delays, reverbs and subtle chorus and flange effects really shine with parallel FX loops.

Input Only (No Loop)

Unfortunately, some amps don't include FX loops. This is really a bummer because it really limits the types of sounds you can get with your amp and still use effects. You can still do it, but you have to be careful. Effects such as delay, chorus and reverb don't do so well if they are placed before distortion and overdrive, so if you want to use your amps distortion, but don't have a loop, you're pretty much out of luck.

Basic Effect Placement Guidelines

As stated earlier, we'll be going over exceptions and alternatives in Part 2, but there are basic guidelines and little tidbits that should be common knowledge before getting in to the deeper stuff. The simplest way to look at effects routing and order is to categorize it as either a "pre drive" or "post drive" effect. A pre drive effect is placed before any distortion or overdrive in the signal chain. These would be placed between the guitar and the amp input using an amp with an FX loop or between the guitar and the first overdrive/distortion pedal using an amp with no loop. Tthe amp without a loop needs to be pretty clean sounding, not overdriven, to avoid FX blurring and muddiness. Below is a good place to get started when placing your effects in order for a good, clean, workable sound. Get your effects arranged using this guide, and we'll look at intentionally messing this up in the next lesson:

Guitar ---> Tuner/Mute ---> Volume Pedal ---> Wah ---> Whammy --->Clean Boost/EQ ---> Compressor ---> Overdrive ---> Distortion (**Or using drive on amp. All effects after distortion are considered "Post Drive" effects) So... either in the FX loop or in front of a clean amp AFTER overdrives and distortions: Harmonizer ---> Chorus/Flange/Rotary/Vibe ---> Tremolo ---> Gate/Noise Reduction ---> Delay ---> Reverb.

If you'll notice, the pre drive effects are placed from 'most mild,' or the least signal altering effect (mute and volume controls), to the most 'extreme.' This is a good rule of thumb when placing your pre drive effects. Also, notice that all of the pre drive effects (with the exception of the whammy which could be considered part of the 'harmonizer family' really works well as a pre or post drive effect) are dynamics altering effects. In other words, they alter the original signal by adding gain, adjusting the volume or a specific frequency area of the guitar signal. They don't add to the signal. Modulation effects such as chorus, flange, reverbs and delays are clearly adding a pitch or time-based element to an existing tone. This distinction, for the most part is what helps classify an effect as a pre or post drive effect. The general guideline is:

Dynamics-based effects should be placed BEFORE the drive circuit (whether a pedal or the distortion on the amp) and time/pitch-based effects should be placed AFTER the drive circuit.

If you read the manuals for most multi-effects units, they explain their signal chain pretty clearly and you may not even have to worry about these basic routing rules when trying to get sounds initially, but many boxes allow you to change around your routing. They also provide what's called a semi-parallel option. This means that your pre drive effects are all run in series (one after the other in an order similar to what is suggested above) but then the signal is sent to a number of post drive effects at the same time and then combined before going to the output. This might look something like this:

This is actually quite a cool way to do things and is difficult to do with individual pedals. One of the advantages here is that you can feed the same signal to two different delay effects at the same time -- eliminating the traditional "first delay messes up the second delay problem." You can also get a cleaner delay/reverb distinction if one is not being fed in to another. This is where multi-effects units really shine!

So, dig out your pedals and effects and start seeing what you can come up with. Stay tuned for some other ideas and techniques in Part 2!