Here starts our understanding vacuum tube guitar amplifiers. We start from the very beginning. What is a guitar amplifier?
A guitar amplifier is composed by three elements:
- The preamp, that gets the low signal generated from the guitar pickups and boosts it in order to make it able to drive the power section
- The power amp, also called the output stage, that takes the output of the preamp and increases the signal energy so it can drive the loudspeakers and produce sound (a lot of sound!)
- The speaker cabinet, a stand alone enclosure that contains one or more speakers (have you ever heard about the so-called “Marshall wall”?)
If the preamp section, the power amp and the loudspeakers are placed in the same cabinet, we have a combo amp. A guitar combo amp is an all-in-one solution, and usually it's not possible to change one of the three parts composing the system. The good news is that the preamp, the power amp and the speakers of a combo guitar amp are perfectly designed to work together, so you don’t have to waste time finding the right settings that make them work good.
When the guitar preamp and the power amp are placed in the same box, we talk of head amp. An head amp has to be connected to an external speakers cabinet. This is a more flexible solution than a combo amp, but it's important to find the speakers cabinet that fits well with the head amp.
The most flexible solution is the rack amp system. In a guitar rack amp, preamp and power amp are separated and distinct. You can connect a Marshall jmp-1 preamp to a Mesa power amp, and send the output to a Peavy cabinet. The setup of a rack system requires some efforts but don't worry, we will see how to get the right sound in the next sections.
Actually there is also a fourth additional option, that consist in connecting your guitar to your computer. Really, there are some powerful software that simulate through digital computation the sounds of guitar amps and pedal effetcs . Results are very realistic . One of the best guitar amp modelling software I tried out is Amplitube by Ik Multimedia. Here's a complete introduction article.
You can have tons of guitar amps and effects all in your laptop . Give it a try, it's worth it (you can have a quick introduction watching the video below).
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