Posted on May 02, 2016
Take a look in the back of your electric guitar amplifier, and you’ll see a row of objects that look like strangely shaped light bulbs. These are the vacuum tubes that your amp runs on. Today, we’ll take a brief (and very elementary) look at what these tubes do. There are three main types of tubes: preamp tubes, power amp tubes, and rectifier tubes.
When the signal from your guitar enters your amp, the first tubes it will hit are the preamp tubes. The preamp tubes are responsible for amplifying the signal enough to feed it to the output tubes. These tubes have a tremendous effect on your overall tone, since this is the first time your electric guitar signal is being amplified.
Simply put, power amp tubes (also known as output tubes) take the signal from the preamp section and amplify to the levels needed by the output transformer, which then sends the signal to your speakers. Even more simply put, the output tubes give you the volume you need from your amp!
The preamp and output tubes in your electric guitar amplifier require DC voltage to operate. When the first amps were being built, the only option for rectifying current was rectifier tubes. In the 1960s, solid state rectification was introduced. Even though your guitar signal never passes through the rectification circuit, the difference between tube and solid state rectification has big implications for both the tone and the feel of the amp. Today, both forms of rectification are common, and can each enhance the personality of an amp given its unique design.
Hopefully, this blog piqued your interest in learning more about electric guitar amplifier tubes. Having a solid knowledge of tubes can help you in your quest for the perfect tone, so we recommend learning as much as you can! Happy tone hunting.