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AOpen Debuts The Funniest Motherboard Ever
Anonymous Coward X-11 writes "Has AOpen gone flipping nuts by putting vacuum tubes on its motherboards?
AX4B-533Tube
No, it's not replacing logic ICs with discrete components. The tubes are part of the on board audio. Not sure if they are serious about this. April 1 was two months ago." As an owner of a tube headphone amplifier I applaud AOpen's move to accomodate the high-end audio enthusiast, while simultaneous wondering about the ability of a switched psu to properly drive a tube amplification stage cleanly. There's no way this is for real, right? Right? Here's a link that seems to work pretty well. And this looks pretty, well, real. Update: /. reader Jedi1USA noted that HardOCP has more pics of the board.
Tubes tend to produce even-order harmonics when they distort. Transistors (except MOSFETS -- others?) produce odd-order harmonics. Of the two, odd-order harmonics are much more annoying from a psycho-acoustic standpoint and lead to what many describe as a "harsh" sound. Tubes also have the advantage of not clipping hard (producing a DC output) because they have to run through transformers to drive speakers and, as we all know, transformers don't pass DC.
That's a gross oversimplification that leaves out much that I know, some that I think I know but don't really, and stuff other people actually know that I don't know at all. But that's the gist of it.
Is it of any use on a motherboard? Sure. It's great gimmick to sell to idiots. So how do they get stereo out of a single tube? It looks too small to be the two-tubes-in-one variety.
I see only one tube and, considering the specs mention 5.1 surround sound, I can't see how this tube could be part of the pre-amp/power amp signal chain. I've owned a few tube amps in my time (stereo, guitar, and bass) and usually there's a couple of 12AX7s in the pre-amp stage and a few 6L6s or EL-34s in the power amp stage per channel. This is one small tube for six channels.
k.
"In spite of everything, I still believe that people are really good at heart." - Anne Frank
I was really hoping for this to be for analog computing.
In the field of chaos theory, and cryptography, and countless others, analog computing is great. To have an analog accelerator, much as one has a 3D accelerator, or floating point module, would be great. The tubes could be rewired on the fly, like an FPGA, allowing the programmer do all kinds of things. Imagine if the programmer could work in voltages, with chaotic effects giving true random numbers. Using this chaotic data, you could form clouds and other random events for games, perform neural network calculations and countless other things.
The analog systems helping the digital ones would be quite a revolution.
-twb
Well, actually it's current that heats up a tube, not voltage, although it's the voltage that shoves the current through the tube's filament. Depending upon design of the tubes filament, the voltage necessary to deliver the filament current (A+) can range from 2 Volts for some "nuvistor" itty-bitty little tubes once used in TV tuners to 35 or 50 Volts for some tubes intended for "hot chassis" radios and TVs that have the various tubes filaments in series across the AC line so that you can drop 85 Volts across a couple of tubes and use the remaining 30 or so Volts for some 6 or 12 Volt tubes.
Most of what are known as "receiving" tubes (tubes used in radios, TVs, and audio amps, including musical instrument amps, tend to use filaments designed for 6 or 12 Volts. If all the tubes in an amp use 6 Volt filaments and/or 12 Volt center-tapped filaments, you can heat 'em all with one secondary winding on the power transformer that they're connected in parallel across (sometimes with AC to DC rectification and filtering in between the secondary and the filaments).
Perhaps you were thinking of the tube's plate voltage (B+), which can run from 40 or 50 Volts up to several hundred. However, not only can you build a switching regulator on a motherboard to change 5 Volts DC to 3.3, but you can also include one that'll step up the voltage. It may not amount to a lot of amperage (current), but it doesn't have to. You can use a transformer on the tube's output to change high voltage, low current to low voltage, high current because power = voltage times current on both sides of that transformer, although a little bit of the power does get used up in the transformer (turns into heat). That output transformer also provides isolation from the high-voltage plate supply.
I only saw the top-down shot where you can almost fail to notice the tube, but it looks a little bit fat to be a 12AX7 or 12AU6 size envelope. I'd go find my old RCA tube manual and try to guess what they might be using, but it's old and falling apart (just like its owner :-), and doesn't need any unnecessary mileage put on it and besides I disremember just what it's currently buried under.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
The math of this is simple - and applies to RF as well as AF. Take two of the signals in the systemm and approximate them for as sin waves. The nonlinearity can be modeled as a power series, so you have terms of the form:
f(a,b) = A*(a + b) + B*(a + b)^2 + C*(a + b)^3...
Substitute
a=sin(w1*t+phi)
b=sin(w2*t)
And do the trig and you can see that you end up with all sorts of neat frequencies such as
w1-w2, 2*w1-w2, etc.
Now, instead of f(a,b), imagine f(a,b,c,d,e,f,g...)_ and you can see the mess that intermodulation makes. It basically mixes (in the frequency domain) all of the signals AND all of their harmonics in all possible combinations!Tube amplifiers *do* sound different because their distortion curves are different than solid state amps. Why audio "purists" prefer one distortion curve to another is what I don't understand. What I want is minimal distortion overall!
But then, audiophiles also buy gigantic cables because they imagine that their speakers will sound better attached to them... etc.
Technical note: The coefficients on the various terms of the power series tend to go down with the order of the term. And, some configurations approximately cancel out all odd or even terms.
The only good weather is bad weather.
Dude, probably about 50% of all new desktop/server/etc. computers have a watchdog timer in them these days. Every new Intel chipset has one including the 845E that this motherboard uses. Some of VIA's chipsets have one. It's really hardly any work at all to put a watchdog into a chipset.
This board is about as useful to the embedded market as a 440hp straight-8 engine would be to a compact car manufacturer.
> high quality audio can only be reproduced outside the electrically noisy environment inside a PC case
Not strictly true--just use adequate RF sheilding. I use my PC for everything, including sound that would even be pleasing to audiophiles who didn't know where it was coming from. I use a modified high-end soundcard sheilded all around down to the sides of the PCI slot, and I've made a DIY Corda-type headphone amp (thanks, Head-Fi.org and Headwize.com!)inside a sheilded drive-bay box. Nothing is truly "external" to the PC, though it may as well be because the effect of the sheilding is the same.
RF sheilding and Faraday cages, people! It *can* be done, with a lot of elbow grease.
Chasing Amy
(We all chase Amy...)
"The more corrupt the state, the more numerous the laws"-Tacitus
Very true. And there's a great story about it. Bob Carver, the amplifier designer, once took one of the much-touted High End tube amps into a test lab and characterized its transfer function. He then built a transistor amp designed to match the transfer function of the tube amp. In blind testing, listeners, even fanatical High End types, couldn't tell the difference.
It didn't sell.
So, partly as a joke, he designed the Carver Silver 7, the most overdesigned tube amplifier ever built. $25,000. All tube. Separate power supply, preamp, and power stage chassis. For each channel. Everything chrome-plated.
It sold. Got great reviews. "Amplifier of the Decade" from The Absolute Sound. Carver must have laughed all the way to the bank.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Water Cooled Tubes are in many high power modern RF transmitters ... I have yet to see a solid state high power AM transmitter. Semiconductors can just not take the power load.
... and was in 1995.
... amazing
Water cooled tubes are designed and built to be water cooled. When I did college radio we had an Old Harris transmitter that use to melt the tubes on us (as in the tube would come out as a glob of glass). We replaced it with a prototype first generation Harris Solid State FM transmitter
Check out Harris for more information on high end RF systems. Hmmm... looks like they do have solid state high power AM transmitters now
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