Effects Loops Demystified!
Hi everyone, welcome back to the Corner, where we’re nothing short of obsessed with our pedalboards this week. Last week, we took a look at our effect pedals and the order we run them in—today, we’re digging a little deeper and talking about effects loops. Some people swear by them, some people loathe them, and some people don’t know what they are or what they do. We’ll try to answer some common questions about effects loops and make everyone nice and comfortable with Send and Return jacks. Cool? Cool.
So what is an effects loop? Basically, an effects loop is an input/output that enables a user to insert effects between the preamp/eq section and the power section of an amplifier. Here’s an example:
Image credit glab.com
Originally amplifiers were built without an effects loop only allowing effects to be run straight into the front of an amp. This arrangement is perfect for the guitarist running an overdrive, fuzz, compressor, or booster or for those using the amplifier for clean tones, running all effects into the front. The problem is when the gain channel of an amplifier is used for an overdrive tone. In general time-based effects like delay and reverb, and modulation effects, like chorus and phase, tend to sound more natural when applied to the signal after it is overdriven. As a basic rule of thumb, most guitarists prefer to add modulation to an already overdriven signal. When the modulation is applied before the overdrive, it can lead to a duller sound or in the case of a delay, the effect could wash out. If a guitarist is using a pedal to achieve the overdriven tone, then there is no problem running all effects into the front of the amp. Usually in this setup, the overdrive and gain or level boosting effects will be first in line after the guitar with time-based and modulation effects coming after. With the introduction of higher gain preamps that produce overdrive, manufacturers started creating effects loops so that modulation and time-based effects could be inserted into the amplifier after the overdrive channel, and before the power amp, thus keeping the overdrive first in line.
Parallel and Series Loops
So now that we have a basic understanding of what an effects loop is and why they exist, let’s look at the two most common types of effects loops. A series loop means that 100% of the signal is interrupted between the preamp and power amp. The signal is sent out of the amplifier via the Send jack, run through the effects of choice, and then returned to the amp via the Return jack. This is the most basic form of effects loop and is perfectly viable for most applications. Since the entire signal is applied to the effects, a series loop may not be the most transparent way to run your pedals depending on the effects used. Series loops are also typically designed for line level effects. In the case of a series loop it’s a good idea to set the effects level controls to minimum and bring it up to match the level of your amplifier with no effects in the loop. This is called Unity Gain.
Much like a professional mixing console, a parallel effects loop splits the signal with the dry signal both sending through the loop and remaining in the amplifier. This allows for greater transparency, as the dry signal never leaves the amplifier 100%. Most parallel loops will have a blend control on them allowing the effected signal from the Return jack to be blended with the dry signal. This allows greater control over effect depth and gives the user control over how much of the effect is present in the output. The catch about parallel loops is that they work best with effects that can output 100% wet signal. Since the dry signal is already present in the amplifier and can be blended via the effects loop, having the dry signal present on the output of the effects themselves can lead to a very faint effected signal. This is why some processors and digital effects have a “kill-dry” function. If your effects cannot output 100% wet signal, a parallel effects loop may not be the best choice.
Tube and Solid State Driven Loops
Now let’s discuss how the effects loop is “driven” and what this means. In order for an effects loop to perform optimally, the signal coming from the Send jack needs to be of similar level to your guitar and low impedance. When this signal is returned it then needs to be amplified. There are effects loops that are op-amp driven and tube driven. The primary difference between is one of headroom and transparency. The typical op-amp that is used is capable of a lower voltage swing than a tube. If the output level of the tube preamp is not taken into consideration when designing a solid state driven loop, these op-amps can be driven into a full clip fairly easily. Keep in mind though that most amplifiers are designed with all these factors in mind and any components in the effects loop, be they solid state or tube, are spec’d out to avoid unnecessary clipping and provide the best possible match for that amplifier. Many builders prefer solid-state loops to tube driven loops because they produce fewer undesirable artifacts. Some will say that a tube adds additional “warmth” to the signal but this is subjective.
To Buffer Or Not to Buffer?
We’ll keep this one simple. Most modern amps come with a buffered effects loop to help compensate for the lower level output of most stompboxes. In a non-buffered effects loop this lower output can cause a somewhat anemic tone. A buffered effects loop makes up for this signal mismatch and cures the problem. If you’re suffering from the woes of a non-buffered effects loop, there are products that are designed to help such as the Ceriatone Klein-Ulator. Most mainstream amplifiers will have a buffered effects loop while boutique amplifier builders may only offer this as an additional option.
Do I Need an Effects Loop?
If you have to ask yourself this question, then you probably don’t need one. As we discussed earlier, the order of effects relative to the source of overdrive can play an important role in getting the perfect tone. If you are running an amp clean or just breaking up, then you probably don’t need an effects loop. If you’re only using a compressor and a boost pedal, you don’t need a loop. If you have 4 chorus pedals, 3 delays, a reverb, 7 phasers, and 3 flangers (hey, it could happen) AND you are getting your overdrive tone from the Lead channel of your amplifier, you would probably benefit from a loop. If you are using the above but getting your overdrive tone from 4 different pedals instead of the amp, you can avoid needing a loop by putting these pedals first in your chain. No matter how many effects you run, if you have a setup similar to the one mentioned (a LOT of effects) you might find that a nicely buffered effects loop can reduce noise and provide a very pristine path for your modulation and delays. Most of the talk about effects order relative to the source of overdrive is a starting point. It certainly won’t hurt anything to run delay and reverb into a fully overdriven amplifier input. While the tones created may not be for everyone, they may be for you so as usual, trust your ears over any articles or opinions.
Now there are pedal-based units out there that provide an effects loop on your pedalboard. These are not the same thing but they do provide some great functionality such as true-bypass for those vintage tone suckers or a blend control such as the Xotic X-Blender. This allows you to mellow out those over the top effects or use a kill-dry function with it to create your own unique blend.
So there it is: effects loops made easy (hopefully). As in all things guitar, whether or not an effects loop is “for you” depends on your ears and no one else’s. I personally like to keep things simple but when cranking the JTM-45, I sometimes wish I had an effects loop for the Echoplex. That being said, I still love the warmth when plugged directly into that sucker so I don’t feel the need to add a loop or get an amp with a loop. As always, we love to hear what you guys are doing with your rigs—if you’ve got any tips or tricks with FX loops, be sure to share them in the comments below!