An Introduction to Guitar Amps
In my last article I covered what to look for while buying a guitar. As bewildering as that can be purchasing an amp can be even worse. What is gain, besides the thing that makes it sound like ac dc? What is a preamp or a power amp? What is this about tubes?
This is not a comprehensive review (or overview) of any amps, but instead is just a helpful guide to get you through the jungle when you are buying a new amp and what to consider.
How an amp works
The amp does more than just make your electric guitar louder. It sends it through a series of circuits that change and color the signal before it actually routes it to the speakers. The diagram below shows how the signal travels through a basic amplifier.
Preamp EQ Poweramp
I am going to present a very simplified version, but if you want to delve deeper you can check out this article. The first stage is your preamp. The preamp “colors” the sound of the guitar signal. A completely “dry” signal sounds a bit like an acoustic guitar. The preamp is where you can get your tones for all your favorite songs. Dialed in, it gives you all your classic sounds whether its a clean guitar like David Gilmore in Run Like Hell or Comfortably Numb or distorted guitar like Nirvana’s Smells Like Teen Spirit. It is also where your gain stages are located. The amount of gain determines how clean or distorted your tone is.
The preamp section is your EQ is located. The EQ is where you can set your treble, mids and bass. EQ is a big a deal and varies widely from style to style. You get some basic settings here.
Your power amp does exactly what you expect it to. It powers the speaker. This can be done either with a transistor source or a series of power tubes. The tubes and transistor each give a different sound and response to the signal they are processing. If you care to delve into the different types of tubes and how they sound here is a great resource.
What do you need?
The biggest thing to try to work out is what do you need in an amp. There are a lot of things to consider when addressing this question so I’m going to break it down into smaller sections.
How will you be using this amp? Is it for small gigs, practice (practice and small gigs), jam sessions, or recording? This only scratches the surface, but each application has very specific requirements. For example there is no real need to have a 30 watt 2×12 amp like a Vox Ac30. But you might be doing enough small gigs that a Blues Junior or Ac15 would work.
Modeling and Fx
For practice you may also consider a smaller amp with a lot of flexibility built in. This is where amp that are also modelers might come in. Some of these can be had easily for under $200 like the Fender Mustang, Vox Valetronix series and amazingly versatile Boss Katana. Each one of these amps also has features that allow you to connect to the internet to download even more sounds. The options and the diversity is too big to go into here but worth checking out. I will be writing a comparison on much more in depth options like the Line 6 Helix, Fractal Audio’s Axe FX and the Kemper Amp Profiler.
The advantage of a modeler is that it includes several different amp sounds including preamp and power amp sounds. Additionally, most allow for several fx to be used at the same time, which for beginner allows you to play with certain sounds on a budget. Speaking of budget….
As always with gear have a price in mind. Don’t shy away from used gear either. Reverb is a great place to look and even Guitar Center has a decent selection that you can try out in store. Here in Colorado, for example, we also have several locations of Music GoRound which carries some great boutique and rare vintage amps, including Rivera, Mesa Boogie and even an ancient Fender Champ. Consequently, you can find great gear at a good price. Most modeling amps range around $200-300 and a good tube amp starts at about $300 used. So, you don’t have to spend $1000 to get a decent amp, but you certainly could.
There are almost as many amp options as there are guitars, consequently it becomes a very personal decision. But if you take into consideration all of the above things, you can land yourself a good amp at a price that fits your budget.