![]() ![]() The grid carries a negative voltage and is connected to an input source, which, in the case of this amp, is a fluctuating audio signal. The Triode In a triode, there is a third electrode in addition to the anode and the cathode, called the grid. However, this isn't much good for amplification, so let's move on to the next step in the vacuum tube hierarchy: the triode. Since electric current flows from negative to positive and never the other way around, the current can only flow one way in a diode. The potential difference is due to another electrode, called the anode or plate, which is positively charged and therefore exerts an attractive force on these enthusiastic little particles, causing them to whip across the vacuum from the negatively charged cathode. If a negatively charged electrode (as in it has an excess of electrons, in tubes it's called the cathode) is heated by a filament, the electrons in it become 'excited' and, if a sufficient electric potential difference or voltage is present, they will actually be emitted from the electrode. Vacuum tubes are said to be thermionic, meaning that heat is used to encourage the emission of electrons from an electrode. The Diode The most basic vacuum tube is a diode, so named because of the two electrodes which it contains. If the interior of the lightbulb were not a vacuum, the filament would experience combustion due to the high temperature in the presence of oxygen and be destroyed. A good example is the early lightbulb, inside of which a filament was subjected to a current which caused it to produce energy in the form of light and heat. A vacuum tube is just a glass tube that's had all the air sucked out of it. In order to appreciate what more or less goes on in this amplifier, we need to take a look at how a few things work, and first up are the vacuum tubes themselves. Quick Intro to Tubes A project such as this one can teach you a lot of about electricity and electronics. An old trick is to keep your left hand in your back pocket all the time, so if you do get shocked, it hopefully won't reach your heart.Īlso, you'll need to know how to read a schematic, solder, and use a hand drill. When testing the amp out for the first time, use something like a twelve volt power brick instead of plugging directly into the wall, just to be safe, as well as to prevent things from exploding or melting. Discharge all capacitors through a resistor connected to ground, preferably with a voltmeter across it to be absolutely sure the cap has completely discharged. Some of the capacitors in this amp will hold onto a charge for a long while after the power has been switched off. If you decide to work on it with the power on, be careful. ![]() It involves high voltages and a lot of current that can make you feel decidedly unpleasant or even decidedly dead. This project is dangerous in a very serious way. Except, of course, for these next few sentences. Keep in mind that I am just a dude on the internet - take everything I say with a grain of salt. Going through the process of purchasing parts, planning, and executing is a useful experience for any maker. You can learn a lot about electricity and electronics from a project such as this. ![]() That being said, they look damn cool, and some people seem to think they sound pretty nice, too. Tube amps, unfortunately, aren't the most practical things in the world they consume a great deal of power, get very hot, and are big. However, tubes can also be used to amplify a stereo signal from another audio source such as a CD or MP3 player. You usually hear about tubes being used in guitar amplifiers, because they distort in a way that suits guitar playing. Vacuum tubes are old electronic components that act like transistors, controlling a lot of current with a little current. Ever wanted to build a highly dangerous, inefficient, yet awesomely retro piece of electronics? Well, I have. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |