What is a Tube Amplifier or Vacuum Tube?
Let us know first the basic principles of electricity. Electricity is compose of electrons which can be found in all atoms and acts as the primary carrier of electricity in solids. If we talk about vacuum then there’s no air and matter to it. Electrons occupy space. Same positive charges repel while opposite charges attract. Way back to history, tests and technical activities are conducted to demonstrate clearly that electrons will not just only occupy space, but they can also be controlled. Researchers proved that, electrons flowing in a vacuum from a metal substance that is being heated which is considered as the cathode attracted to a positive charged substance known as the anode can be drawn by a magnetic field.
So amps in musical instruments such as a guitar, we’re very interested in manipulating the said electrons rather than showing images with our tube amps.
It goes like this: We can see a glass envelope In the center of a tube which is a negatively charge element that carries just a minimal number of anode (positive charge), and it releases a countless electrons when it’s ready to be heated. Anode surrounds the cathode typically call it as the plate. The plate that carries anode are ready to pull the cathode’s electrons towards it. The anode’s plate, the cathode’s minimal positive charge makes the cathode seem to be negative. In a vacuum, these two elements if you put it in and power these up, electrons will react towards the plate. Adding the third element which is the grid of the two, then scientifically the electrons can be under control. Therefore, when you place cathode close to the grid and connect it, the grid to the relatively small amount of voltage coming from your musical instrument or device pickups, it can create something amazing: Small signals produce plenty of electrons, with this making the electrons travel to the plate. Electrons rushing from the cathode to the plate reflecting the signal from the device, amplifying to create multiple signals.
Now, let’s go back to cathode. Electric voltage is definitely relative because same charges repel while opposite charges attract known as the law of reaction. Therefore, cathode close to the negative grid will keep those electrons with negative charges in the right position until the musical instrument’s signal is ready to strike the grid positively to release them.