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Happy 100th To The Vacuum Tube
williamw83 writes "Today, November 16, 2004 has been declared as the centennial of the birth of modern electronics by the American Vacuum Society. As the AIP Physics News Update reports, this marks 'British scientist John Ambrose Fleming's 1904 invention of the first practical electronic device. Known as the thermionic diode, this first simple vacuum tube, containing only two electrodes, could be used to convert an alternating current (AC) to a direct current (DC).' Today's celebration takes place as part of the AVS's 51st Annual Symposium & Exhibition in Anaheim, CA. Being a guitar player myself, I've come to truly appreciate the technology of the vacuum tube every time I crank up my amplifier. This 100-year-old grandfather of electronics, used by musicians and audiophiles across the world, has proven that profound advances in technology do not always render old technologies obsolete."
It's a shame that more audio electronics don't use tubes. the warm sound simply can't be beat...
It'll be a shameless plug, but here are some pics of some REAL nice tubes in action...
http://www.firebottles.com/
Enjoy...
My
Our only hope in case of an EMP (/nuclear). Vacuum tubes may be ugly and power hungry, but they are much more likely to withstand huge electromagnetic pulses (malicious or otherwise).
cool.
They glow. Seriously, that's why I think they are cool. Anything that warms up has a nice feel to it. Old radios sound very interesting as they come to life. After the click of the power switch, first nothing, then a low hum that is replaced by subtle noise as it drops, then finally the audio creeps into the foreground. Soon after comes the smell of dust burning..
I had a chance to build some vacuum tube projects in the late 80s. (We had lots of tubes and nothing else to do.) Made a power supply for the older speakers that featured electromagnets on the back to revive an old tube radio.
Tubes forever!
Blogging because I can...
As a guitarist who is a tube nut (currently own a Mesa Mark IV and a Rivera TBR-1SL), I'm a bit disappointed to see that nobody has improved the vacuum tube at all since it was abandoned in the mainstream for the solid state transistor. It's a well known fact that guitar amplifiers produce more pleasing sounds when the tubes run hot, but amps which are known for running the tubes hot (such as the Vox AC30) are also known for blowing tubes. Why haven't we made tempered glass (Pyrex?) tubes built to run at higher temperaturesr. Why haven't we applied newer technologies to produce better tubes? It also seems odd to me that tubes made today don't seem to last any longer than tubes made 50 years ago.
The TVs my family had when I was a kid used tubes. So did my father's clunk old mono "HiFi" pre-amp/amp. They glowed and smelled neat and took forever to warm up.
When a tube went bad, we had to go to . . . the drug store.
There was a white-painted masonite kiosk there. It had a board on top where you could plug in a tube. There were a few different sockets. I forget how they indicated success or failure.
The kiosk had a locked cabinet where the spares were kept. I can't imagine there were more than a couple of dozen types there, and I suspect it was a lot less than that.
Stefan
Yes vacuum tubes were invented 100 years ago, but it wasn't until much later that Howard Armstrong perfected them such that they could be used as amplifiers. I think he was certainly an un-sung hero. He perfected the vacuum tube, then he invented the super hederodyne circuit used in modern AM radios. Later he go so upset at the static and poor quality of AM that he turned around and invented FM. A great story with a tragic ending -- he ended up killing himself by jumping out of a tall building. This is of course after years of patent battles with RCA (the microsoft of their day.)
I've got some tube type shortwave receivers including a Hammarlund HQ-129X ca. 1946, a Hallicrafters S-38 ca. 1946, a Collins 75A-2 ca. 1952 and a transmitter, a Heathkit DX-40, all in good working condition. Radios like this are often referred to as "Boat Anchors"
There are quite a number of Ham radio transmitting power amplifiers from various manufacturers on the market that use tubes, too.
73 - K9LJB
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain "Boat Anchors"
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain
Total Harmonic Distortion less than 0.5% at rated power (40 watts) 20-20,000 Hz
Intermodulation Distortion less than 0.5% at peaks twice rated power.
Distortion at normal listening levels of under 1 watt is well below 0.1% . Point me to any auditory studies which claim this is audible. Tube preamps do much better still.
Incidentally, the 2nd harmonic argument is generally incorrect applied to most mainstream audiophile tube components. An amplifier's harmonic envelope is determined by the linearity of the base amplifier and the amount of feedback applied. More feedback eliminates even order harmonics (that would be the second) faster than odd. It's a good bet the bulk of the MC250's distortion is odd-order.
On the other hand, maybe I should just shut up. It was another "rational mind" who told me I could have this amp gratis almost 20 years ago. The solid state receiver and 50 watt Bryston amp I had at the time have little to no value now, this one still commands well over $1000 US on the international market. You know, you're right! Toobs do suck!
More money is made in selling replacement tubes :) Seriously, most tube people are to drop the cash on it. Those that aren't switch to transistor. It used to be you couldn't get that nice warm sound with transistors, they just don't distort the sound in teh same way as tubes. Well, DSPs have changed all that. You can get quite a large amount of signal processing for quite a small amount of silicon. The tube modeling amps are really quite good these days.
As an example of one that just rocks (albeit impractical for stage), check out Native Instrument's Guitar Rig. It's software for the PC. Unprocessed (as in no amp, mic or anything) electric guitar goes in, great sound comes out. Clean, distorted, whatever you want. Build a virtual rack of amps, EQs, speakers, mics, etc and it models them to a high degree of accuracy. It's quite impressive.
So for most people concerned about money, something that models a tube amp is good enough. The purists, well they'll spend the money on the tubes.
Also, though I'm not 100% certian, I think that part of what gives that nice warm fuzz is running a tube up past it's limit. Unlike transistors, which are basically linear to a point then just stop pasisng more power, tubes are fairly linear then start curving off more and more, and increasing in distortion. So to get that real warm sound, you run them past their linear phase.
So if you built a tube with better characteristics, stands to reason you'd just have to drive it that much harder to get what you want. As I said, not sure on this, but I'm guessing it's part of the reason.
I'm surprised no one realizes nearly ever radio or TV transmitter outputting 1,000's of watts or more uses tubes, albeit ceramic tubes rather than glass ones in most cases. And this is today in late 2004. Although in the most technical sense they are "amplifiers", they aren't audio amps. The transmitter tubes often have metal fins to radiate heat and a "chimney" to air cool the tube. This technology could be adapted to "hot" guitar amps, although they would be pricey.
In all seriousness, the tube market today is relying on the sale of tubes that for the most part were made 50 years ago, or with tubes imported from the former Soviet Union or China. The Soviet/Chinese tubes have become a mainstay for hams running 1KW class linear amplifiers, and there is a steady market for types such as 4CX500, 3-500Z, and so on.
Sadly, for many antique radio restorers, the prices and lack of availability of certain tube types keep many promising projects on the shelves, and many of the radios that used those tubes are usually found stripped of them. A late '20s or early '30s console will almost always have the type 45 tubes stripped out.
At the same time, just about anyone who has acquired box lots of tubes will tell you that 90 percent of the tubes will never get used. A lot of these tubes were manufactured as replacements in 1960s era TV sets, and in a way were the first "integrated circuits", but have little use outside these roles. They were made by the tens of millions, but were made obsolete by the quick adoption of solid state circuitry in the 1970s. Few people collect or maintain 1960s era TV sets, but the old tubes stay around just as the 1mb memory sticks collect in many modern day geeks junk boxes. Other tubes, such as the combinations used in many '40s and '50s radios are available in adequate supply, either with tube vendors at hamfests or online for the forseeable future, or could be pirated from undesirable radios.
It is just too expensive to do small scale tube production to satisfy the needs of a few thousand antique radio collectors and amplifier restorers. Inquiries were actually made to one of the Russian manufacturers to start producing new Type 45 or similar tubes. A run of a few thousand would satisfy the needs of collectors for years, but the unit costs are as high or higher than buying New Old Stock where it can be found.
I have been somewhat inactive at the restoration game for a few years, but I remember when a major antique radio club looked into having one of the Russian or Eastern European manufacturers build some new highly sought after types, the combination of minimum quantities and unit cost would have risked tens of thousands of dollars, for a product that has a very limited market. Perhaps the ability to sell to a worldwide market easily, ala eBay might make it feasible today, but it would still be a risky proposition.
There are other tube types that would be welcome if they could be produced economically with a limited run, such as 7360, 1L6, and probably a couple of dozen other types. Perhaps a modern cottage industry could pick up the slack.
I gotta wonder---do I sound like this when I'm geeking out about discovering a whole nifty set of panorama-stitching tools, going on about Laplacian pyramids, control points, barrel distortion and such?
No wonder the non-dorks I talk to get such a glazed look in their eyes when I tell them what I'm currently interested in.
--grendel drago
Laws do not persuade just because they threaten. --Seneca
Actually that is not so. Tubes are the most linear amplifying devices. http://www.dogstar.dantimax.dk/tubestuf/miniblk1.h tm
Bzzzzt. This is absolutely false. In terms of dynamic range, the most linear amplifiers are *clearly* transistors. In my line of work, you'd be laughed out of the room if you dared to use vaccuum tube amps. For RF situations requiring very high dynamic range, vacuum tubes are *not* an option. Tubes are *not* used for truly high dynamic range applications.
Audiophiles do *not* have high dynamic range demands compared to some radar applications; and in these radar applications, there is no room for parlor quibbles about soft-clipping and warmer sounds and harmonics. There is only reality, in the form of whether or not you notice the incoming missile. So, please. I think it is a fine thing for audiophiles to blow kilobucks on tubes to make their guitars sound optimally crappy.
Everyone needs a hobby.