Most amps today have more sockets than just “input”. Chances are, your amp also has two labeled “send” and “return” – the Effects Loop. What’s it good for other than a feature that might give the salesman more to talk about?
The signal that “travels” through your amplifier normally takes the following route: Input – Preamp with EQ section (generally responsible for sound and – if you want – overdrive) – Power amp (generally responsible for volume, although with tube power amps the sound is also shaped).
All well and good, the problem is that some effects (modulating effects like chorus or delay effects like delay and reverb) work and sound better if they come after any distortion or gain that is applied to your guitar signal. For example, it would not sound too good if you put the reverb before the overdrive. Why is that so? In short, you want a reverb on your overdriven signal, not an overdriven reverb.
There are some basic rules that “govern” where to put effects in the signal chain (I’ll add more specific information in later articles when talking about the specific effects):
- If the effect modulates the signal, put it after any preamps or overdrive/distortion boxes.
- If the effect boosts the signal, put it before overdrive (a compressor for example).
- There are no rules! Break them, experiment!
Now without the effect loop, all you can do is put your effect boxes between your guitar and the input of the amp. If you use an overdrive/distortion box for your sound and not the amp’s “hot” channel, all is well as long as you remember to have the overdrive/distortion among the first effects your signal travels through, in most cases before effects like chorus, delay, reverb, flanger etc (see text above).
But if you use your amp’s overdrive channel, you get the problems described above (the effect box with the delay now comes before the overdrive). This is where the effect loop comes in. The guitar signal comes from your amp’s preamp and through “send” goes into those effects that should be put behind any overdrive. The signal comes back into your amp through the “return” socket. There are little switches inside these sockets that make sure the signal goes to the right place, depending on whether a cable is plugged in or not. Therefore, you should have all the stomp boxes that should come before overdrive between your guitar and the amp’s input and all the boxes that should come after overdrive after your amp’s preamp in the effect loop.
“Ok, but I’ve got a multi-efx unit – what can I do now?” (Please note that in my eyes, something like a POD is just a sort of multi-efx: different effects – overdrive being an effect – and a way to save the parameters and sounds)?
If you want to use your amp only to amplify the great sounds you’ve programmed into your multi, you don’t want the signal to pass the amp’s preamp because the preamp EQ section will color that sound. You want the signal to go straight to the power amp. So the signal path is: guitar – multi efx input – multi efx output – amp “return”. Remember to switch off the multi-efx’s “speaker simulation” – you don’t need it, your amp has a guitar speaker, so why emulate one in addition?
If you want to use your amp’s sound, things get more complicated.
- a) easy way of doing it: Use your amp’s clean and overdrive sounds and the multi-efx only to provide the effects that should come after overdrive/distortion. Put the multi into the effect loop.
- b) But I want the full monty: I want to use the overdrive sounds of my amp and my multi and the effects of my multi-efx that usually come before overdrive (compressor for example)! Gulp … just hope your multi-efx has an effect loop, too. The signal path then is: guitar – multi – efx input – multi efx “send” (the signal has now passed the effects that should come before gain and the multi’s overdrive section) – amp input – amp “send” (the signal has now passed the gain section of the amp) – multi-efx “return” – multi-efx output (the signal has now passed the effects that belong after the gain stage) – amp’s “return” – the signal now “reaches” the power amp.
Try it, but remember to turn the volume down before you switch everything on – you might have to adjust quite a bit of controls to make it work (the volume and gain controls of your multi’s effects, the input sensitivity of the multi …)
Some amps have a series others a parallel effect loop. With a series effect loop, the guitar signal (=your sound) comes from the preamp of your amp, “leaves” your amp through the send jack, runs through the inserted effect and comes back through the return jack. 100% of your signal goes through the effect. Many people have found that their sound suffers (great tube amps and – perhaps cheaper – digital effects => maybe loss of sound).
The solution was the parallel loop: with the control, you control how much of your original signal leaves the amp and passes through the effect. The “remaining” signal stays in your amp, preserving much of your sound, and is “joined” again by the signal coming back from the effect, now with effects on it. So you can mix the dry (without effect) and the wet (with effects) signals, but keep in mind that you won’t hear much of the effects if you only put a tiny part of your signal through the effect box. The effects in the loop should be set so that they let out no original signal but 100% effect signal. You decide with the parallel effect knob how much effect you want.
Hope you’re still with me next time when we start talking about the individual effects.
About the Author
Stefan has been playing guitar on and off for about 20 years, with 10 years of teaching privately and one year in the professional program of the “Future Music School” in Aschaffenburg, Germany. When playing guitar Stefan usually plays a lot of blues and blues-influenced (classic) rock, but when writing songs, he ends up writing rock and even pop songs.