THE EFFECTS LOOP: what it is and how to use it

Hello and welcome to this week's article! Today we're going to talk about an important aspect of every amplifier and mixer: the FX LOOP!
What is it?
The effects loop, talking practically, it's a part of a sound's Signal Chain (Click here for a dedicated article!), set between the preamplifier and the power amp (therefore, AFTER the Gain Related Area), and its relevance has been increasing through the years with the increasing of the amount of gain required from the players: if we set a Delay BEFORE the Gain Related Area, the repetitions will be distorted as well, often with chaotic results if the gain is high.
To make sure the effect is clean, the only solution is to set it after the gain area, and that's what the Fx Loop is for: we're going to take the signal of our preamplifier (and therefore of any stompbox set in the input of the amp) from the SEND out and we're gonna send it to the IN of our effect (for example, a modulation unit), then we will go from the OUT of our effect to the power amp via the RETURN of our amplifier.

There are two types of Loop Connections: Serial and Parallel.

- Serial: This is the simpliest connection, and it's the aforementioned one: Guitar -> Preamp -> effect -> Power Amp.
The upsides of this connection are the simplicity and the compatibility with any effect, the downside is that usually, except for the most expensive amplifiers, the signal with effects in the loop gets slighly degraded.

- Parallel: in this case we could say that the signal is split in two: part of the signal will be effected (Wet) and part will not (Dry). Most of the times, in amplifiers that features a parallel loop will even be possible to choose between Serial and Parallel; to know if our amplifier features a serial or parallel loop we just need to connect a jack cable in the send out: if our amp becomes mute, the loop is Serial.
The upsides of this connection are the fact that the Dry signal is not degraded, since it doesn't pass from the loop, the downside is that we will have less flexibility, and that if we use a digital
effect we're gonna set the signal to 100% Wet, because due to the AD-DA conversion, the processed signal could be slighly delayed, generating unpleasant results when used together with the Dry one.
Finally, since Parallel loop effects only one part of the signal, if we use a Booster, or an Equalizer or a Tremolo, they won't affect the Dry sound, and will lose most of their effectiveness.


Some digital floorboards (such as the Pod Hd or the latest Digitech ones) also lets the user to connect them with a Four Cable Mode, in order to separate correctly the effects that needs to go in the Input of the amp from the ones that must go in the Loop, and to connect them to the correct plugs while still using the preamp of the amplifier, without replacing it with the digital one (if we wanted to use just the preamp of the floorboard the connection would have been much easier: Guitar -> Floorboard -> Return of the amp).

Finally, there is an Effect Loop in the mixer too, in order to connect an external hardware or software unit and to place the effect after the Channel Preamps. The Dry-to-Wet ratio is controlled by the FX control present in the channel. This feature is present in the DAW mixers too, and the process of loading an effect and sending it to the various tracks in different amounts is explained in the article dedicated to the FX TRACKS.


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