Get an old CRT TV and you can do the same thing. It can permanently distort the picture. I'm not sure why that is but I managed to ruin mum and dad's 26" colour telly in the early 80s with a magnet lol
Weird: I'm still not through all of the Sixty Symbols videos, after being subscribed to this channel for years, already. Seeing those big, fat tubes instantly brings back my memory of my first electric shock! My dad and I were at the local hardware store. This was no later than 1968, and our TV was on the blink. My dad, of course, was testing various tubes to find the broken one, and I, of course, couldn't help but to put my finger into one of the tube tester' sockets. OUCH! I was shocked!
Cool video. I remember studying thermionic valves at college many years ago. They are quite nostalgic for me now. Especially as I have them in my guitar amplifier. Who remembers a TV full of them?
I like that something that hasn't been cutting edge science for 100 years is still explained and completely new to most people. Too often I think we don't look at how we got to our modern age.
Great summary of thermionic diode and triode. TY for posting. BTW if I'm not mistaken the thermionic emission of electrons from a heated cathode is sometimes called the Edison effect. The emission process itself is analogous to evaporation of particles (electrons) from a 'liquid-ish' phase (confined in the metal) into a gaseous state. Raising a cold cathode voltage eventually causes field emission. Which can image the molecular structure of the emitter, as in the field emission microscope.
My dad works with vacuum tubes all the time making power supplies for radars handling up to hundreds of thousands of watts. The amusing thing is a politician came along to look at the plant and declared "one day, technology will replace all these devices with microchips." Clearly did not understand fairly simple physics involved in cramming a quarter million watts through a square centimeter of silicon.
@sixtysymbols Well for me at least :P My body was just about to be cured from the addiction of sixtysymbols videos and now here it is again!!!! I hope you have some kind of Christmas special :)
The amplified current flows through an electromagnet coil which moves the magnet connected cone at the corresponding frequency. The air pushed by the cone at this frequency (think of waves) is the sound you hear. A microphone works in the exact opposite way. The sound (air) flows in pushing a magnet, which changes the magnetic field in a coil (electromagnet), which induces a current. Then you can amplify this current with a tube, and put it through a speaker.
Despite, or maybe because of, my electrical engineering education and experience, I still have a passion for vacuum tubes. I have yet to kill one via ESD; their inherent "non-linearity" particularly in guitar amplifiers gives them beautiful acoustic qualities I have yet to hear in a transistor amplifier, and heck, it's just plain cool to see those glowing heaters. Even when the tubes are "dying", they put on a show, glowing an electric blue when you play aggressively.
Tube amplifiers are used by a vast majority of electric guitar players. Compared to the solid state (transistor) amps, tube amps produce deeper, warmer and more rich sound. Although, new generation digital amps can really well emulate the sound of tube amps, for long years they were unbeatable.
Nice drawing of Nikola Tesla's lecture w/fluorescent tubes. Trivium: In a much later interview Tesla couldn't see what the big interest in vacuum triodes was about ...since he'd invented them in secret and had been using them prior to 1900. So he says.
Almost every TV and radio broadcast you see and hear passes through a tube. Tubes are still the best way to go for high power transmission. So when you need to output 1500 or 15000 watts you use a tube for that.
@cuntylishus actually, there is more to why people like tube amplifiers. One of the biggest is how tubes tend to alter the transients of a sound source. Because tubes tend to react slower to passing signals then transistors, the result causes the transients (initial spike in an audio wave) to become rounded off. Because of this it is interpreted by the brain to be more natural and pleasing when compared to transistors. This is why most guitar players use tube amplifiers. It is quite noticeable.
The reason vacuum tubes have to be evacuated is that any air in the tube would ionize and cause an arc if the tubes were operated at high enough voltage, and that would really suck because a high-power vacuum tube failing can be quite dangerous and expensive.
It isn't so much the nishe aspect so much as the power supplies you need to operate a tube amplifier that drive up the cost, those require large power transformers that can deliver higher voltages and higher current in relation to solid state equipment. There are niche market tube amps with greatly inflated prices but there are more production oriented ones that don't use rare or exotic tubes as well.
One thing, cathode ray technology, as old as it is, is also the only technology capable of being used in digital components that can withstand EMPs. Just a fun fact.
Years ago, I was confused when I first heard the term "valve" to refer to what I always knew as a "vacuum tube" -- but I now have to admit, "valve" *is* a better word than "tube"!
A little bit of a disservice to fail to acknowledge that the first valve was actually invented at UCL by Sir John Ambrose Fleming rather than at Nottingham.
In the speak there is a very strong magnet, if you get another magnet close to it those two will most likely smash together damaging paper thin membrane, hence damaging the speaker.
Solid state technology is quickly taking over for high power applications to replace vacuum tubes. Many of the new high power microwave and broadcast systems are completely solid state. For a while more, there will still be some need for very specific types of vacuum tubes. Eventually, they will be completely phased out. In looking at the basic light bulb, the CFL, and LED technology has taken hold. Soon it will be high illumination electro-luminescence technology.
And to think computers were once built with these... My oscilloscope uses CRT too; call me old fashioned but I still prefer vector over dot matrix :) When I was a kid, my dad brought home some old military electronics books; all valve stuff. Just to give you some idea how old these books were, the last in the series was on transistors and had "TOP SECRET" all over it :P
no they cost more because there is less demand for it and they do actually cost more to make because of the vacuum involved. also they get hot too so they need heatsinks, like the two silver boxed on the end of the amp thats in the video, to disperse the heat. which again adds cost.
Except that the transistor is a solid state device, where the thermionic valve is a vacuum device. BTW, the operation of the valve looks much more like that of a FET than of a bipolar junction transistor.
@Envergure i have a tube amp and they are very fragile, you cant turn it on and just rock heavy metal, you have to let the amp "warm up" and thats why most amps have a standby" function so your not on and you can let the tubes inside your amp warm up so they dont burst when played hard. Yes tube amps sound better.. much less digital if u run alot of effects or tones :) however vox, as any amp company sells tube amps. Their is nothing particularly special about Vox's! thanks
Since the 1950s actually. Though for the high powers aluisious talks about (hundreds of thousands of watts) transistors are far less effective and way too expensive. (You would need thousands of them in parallel)
***** He doesn't seem to know that the distortion caused by solid state devices is more accurate lol. Solid state distortion is actually how the sound really is. If I find the place where I read that I will give it to you, but I'm not sure if I can find it, I read that years ago.
Haha, I seriously doubt there's any studies about it, I just know the physics behind solid-state vs. tube amps. Vacuum tubes can typically generate a lot more current/signal gain, but with an inherent inaccuracy/uncontrollability caused by electrons flying through a vacuum
George Kotsonis There are studies indeed. the fact is that the tubes have a cuadratic law transfer function(current vs grid tension..), which means you'll have even harmonics summed to the original signal, which are nice to the human ear...the solid state devices (BJT transistors), when working in class A have no distortion at all, because they work in a linear region...
You obviously haven't realized how utterly focused on politics (as opposed to things like science, economics, law, or other important issues) most politicians are. We see the most exceptional ones on TV all the time, as presidents and majority leaders, but most of them are honestly being taxed to their limit remembering the name of the Water Authority Director's wife.
