Ok, so you’ve mastered a few licks and chords now you’re all set to become a fully fledged guitar hero. Before you take the plunge you need to find out here how your amplifier works and how to get the best from it. I’m not going to bore you with an electronics lesson but it does help to know what each of the controls does and how to get a few basic sounds. This marshall AVT-20 is a simple entry level amp with a control panel that should be pretty similar to what you have at home. The controls are over drive channel switch, gain, volume, bass, middle, treble and revurb depth. You can also see inputs for plugging in a CD or MP3 player to jam along with or headphones for silent practise which is probably your next door neighbour’s favourite feature.
First things first, plug your guitar into the input jack socket like this, power up your amp using the power switch like this but keep the volume control down on your guitar for now. First up is the channel switch, if you have a tube channel amp like this then it may be labelled as high gain, overdrive, distortion or simply channel B but basically it allows you to switch between 2 different amp sounds. The most common set up is to have one sound dialled in the mellow and clean line like this [music] And another rockier sound available like this.
On this amp whichever channel you have selected, turning the gain controller up adds distortion or overdrive to the sounds while the volume is a master control that sets the overall output level of the amp, without going into the science, most practice amps will have an equivalent to the gain control, this might be called drive, overdrive, dirt, distortion or something similar.
Basically the more you turn it up, the closer your guitar sound will get to rock and heavy metal territory. Next the bass, middle and treble controls comprise the EQ and they work in very much the same way as they would on a home hi-fi sytstem, so if you think your sound is a little bit thin and scratchy like this.
Then add something at the bottom end with the bass control like this.
Similarly, if everything sounds a little bit wooley and lacking in definition then add some high end with the treble control. Other than volume the middle control is in many ways the most important control on your amplifier. Much of an amplified guitar sound sits in the mid frequencies, so if we set up a fairly overdriven sound, you can hear how the sweep of the middle control drastically alters the type of sound that you get. With the mids rolled back it’s much more heavy metal.
But with the mids boosted the sound becomes much more like a classic 1970’s rock tone.
Distorted sounds with the middle rolled back are often referred to as scooped, if you think of a graphic equaliser, imagine a V shape with the middle literally scooped out. Sounds like this work well for heavy metal riffing in isolation and are lots of fun to play be warned though if you intend to play in a band, you might find it difficult to hear the guitar properly unless you add more middle frequencies in. Finally the revurb control, short for revurberation is useful for adding ambiance as you turn up the control, it sounds like your amplifier is in a progressive opening space like the difference between being in a bathroom and a cathedral, here’s a low revurb set up.
Now listen to the difference when we turn the control all the way up.
However, there are a couple of things to consider, revurb sounds tend to be quite forgiving in terms of technique, so if you’re practising hard and really working on something, it’s worth getting used to how it sounds without the effect engaged, as you’ll generally hear your mistakes a lot more easily. Also it tends to be nicer on clean sounds than dirty ones, as it can amplify the mush of the heavily distorted part and make the sound muddy and indistinct. Anyway that should be more than enough to get you started, just remember to not subject those delicate little ears to prolonged periods of high volume.