One of the key factors that create the tone of a guitar or bass amplifier is the type of tubes it uses.
Tubes, some call them valves, are of different kinds, sizes, and characteristics. But there are two main types of amp tubes in guitar amplifiers – preamp and power tubes.
Preamp tubes, as the name suggests are responsible for the preamp section of an amplifier, and a power tube works in a power section. Both types of tubes work together to provide the amplification needed for an amplifier to produce sound.
In this amp tube guide, I will explain how different preamp and power tubes are and how they work in general.
What’s The Difference Between Preamp and Power Tubes?
Preamp tubes and power tubes may seem similar at first glance, but they have distinct functions and characteristics.
But more importantly, power and preamp tubes do very different things for guitar or bass amplifiers and you should know how they work.
Most guitar and bass amps have multiple power and preamp tubes, especially high-wattage amps, but some amps might have one preamp and one power tube.
Also, there are amps that have only a preamp or a power tube that we call hybrid guitar amps.
What Do Preamp Tubes Do?
Preamp tubes are responsible for amplifying the initial signal coming from your instrument and shaping the tone of the amplifier, while power tubes amplify the signal further and produce the sound we hear coming from the amplifier.
These types of tubes are smaller and located in the preamp section of the amplifier, while power tubes are larger and located in the power amp section.
Preamp and power tubes also have different characteristics that affect the tone and performance of an amplifier. Preamp tubes have a greater impact on the tone of the amplifier, while power tubes have a greater impact on the volume and power output.
For example, if you want to increase the gain and warmth of your amplifier, you might choose higher-gain preamp tubes. On the other hand, to increase the volume and power output of your amplifier, you will need higher-power power tubes.
There are several different types of preamp tubes, each with its own specific characteristics. Some common types of preamp tubes include 12AX7, 12AT7, and 12AU7.
The type of preamp tubes you use can significantly affect the tone and gain of your amplifier. Some offer a bright tone, some are warmer, and some are great for hi-gain.
What Do Power Tubes Do?
Power tubes are larger vacuum tubes that amplify the signals coming from the preamp tubes and produce the sound we hear coming from the amplifier. They are located in the power amp section of an amp.
Power tubes are responsible for driving the speaker of the amplifier and producing the volume we hear.
They are also responsible for adding some of the characteristic overdrive and distortion sounds that we associate with tube amplifiers.
Like preamp tubes, the type of power tubes you use can significantly affect the sound of your amplifier.
Different types of power tubes have different flavors and will have an impact on the sound volume and characteristics.
Some of the most popular guitar amp power tubes are 6L6, EL34, 6V6, and others.
Experimenting with different types of power tubes can help you find the perfect balance of volume and tone for your music.
Power and preamp tubes are essential components of an amplifier, each with its own specific functions and characteristics. And the tubes are the reason why we all love tube amplifiers. Knowing how two types of amp tubes differ will give you an idea of how tube amps work and produce their famous sound.