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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.
I bet you've got a 12AX7 on there, considering they said it had a 'dual triode' tube in there. They're also some of the cheapest valves out there.
Detachment 3 Media
Exposed, Exploited, Exploded
There aren't enough components on the board (that I can see) unless there is an external power supply.
Most tubes are going to require abot 16,000 volts to the grid. You'll need a nice-sized transformer to step up normal line current to that. And if it's powered off the MB power harness.....well, I son't think that's even possible. What's the highest voltage there? 12v? That trnasformer would have to be huge.
And all of that isn't even taking in to account the heat problems.
Do not fold, spindle or mutilate.
Neat photo, but a couple of problems:
Chrisd's right on about the power supply, valves have pretty demanding power requirements, and the voltage is much higher (300+ volts is typical) than what's normally present in a PC.
Also, most tube amps require output transformers, which is noticably absent from the photo.
Thirdly, there's only one tube! Presumably, if they are really after the audiophile market, it would at least be a stereo amplifier. Not to say anything about the noise problems present near high speed digital circuits. This is bunk.
You can also check out a IEEE story they link to about vacuum tubes and their uses in modern audio.
I can tell you that no serious music (tech) lover will take this seriously.
Most musicians are not engineers, and vice/versa. (I happen to be both, so I'll be glad to translate). Musicians are interested in sound production, and everyone else in sound REproduction. These are two totally unrelated things. A guitar amp is SUPPOSED to add distortion and tonal coloration to the signal. In fact tests for frequency response and distortion as applied to Hi-Fidelity equipment mean nothing when done on a guitar amplifier. We WANT to modify the original sound. That's exactly what the designers at Martin were doing from day 1. An acoustic guitar has a resonating chamber, a sound hole, and a front and back surface that act as diaphragms. If we could plot the frequency response of a single string played back on a good acoustic guitar, we would see all kinds of nastiness. Violins... the same thing. Saxophones... ditto. Pianos... of course. The sound quality of an instrument, what we call timbre (pronounced tam'ber) is a highly desired characteristic. It's what separates the Steinways from the Wulitzer uprights and the Martins from the Hondos, you get the idea.
In an electric instrument, there are no resonating chambers to add flavor, so we add it with distortion instead. Distortion, the crux of the biscuit..... sometimes we want it, other times we don't. That's what always bugs engineers and audiophiles alike. When you're trying to REproduce an already distorted sound, you don't want to add any additional distortion from the amplifiers. And you certainly don't want to add transistor distortion products. Sometimes tube distortion on a clean signal is OK. What, did I just contradict myself? No way, Jose'.
Here's the point of this whole exercise:
TUBE AMPLIFIERS SOUND DIFFERENT FROM TRANSISTOR AMPLIFIERS PRIMARILY WHEN THEY DISTORT!
You can see it on a o'scope, hear it with your ears, and prove it on paper, so I know it's true. And here's why: Transistors and tubes use different principles of physics for operation. Valve amps (the original name for tube amplifiers) are basically voltage driven, so when they distort, even-order harmonics are produced (2nd, 4th, 6th, etc...) while transistor amps are current driven and produce odd-order harmonics (3rd, 5th, 7th, etc....) When you look at them both on an oscilloscope, the transistor amp flattens out the waveform, while the tube amp sort of makes a triangle wave. If we look at the inherent resonances of acoustic instruments we find that things like violins make lots of even order harmonics, while things like clarinets make lots of odd order harmonics.
Now, do we want our guitar to sound more like a violin, or a clarinet? Ah yes, the violin is much more "sweet" sounding. That's because the human brain likes and will tolerate much more even-order distortion than it will odd-order. One of the great distortion boxes in recent history is the Aphex Aural Exciter. The guys who designed this thing were marketing geniuses. The original units were sealed boxes with tamper proof hardware. They were leased to studios for final mix down. Once a few big artists like Linda Rondstat and Fleetwood Mac used and liked them, their place in audio gadgetry was assured. Of course they just use a clever method of picking out the fundamental note of say a human voice, making a little distortion, and adding it back to the original signal. This adds "warmth" or "depth" to the sound that can be, well, exciting. Our theory about odd vs. even distortion holds up because while the first units made lots of odd harmonics, several years later I remember an engineering release that hyped a new distortion circuit with increased the 2nd order distortions, while reducing the 3rd order products. Sound's very interesting doesn't it? They made a way to produce "tube" sound in a device that's basically used on vocals and strings. Again, the brain likes even-order distortion while finding odd-order somewhat irritating.
There's some tricks to be used for making distortion. You can get transistors that are voltage driven called MOSFETS. In my opinion, they can be made to sound like tubes if properly designed. Also, once a signal is digitized, it can be made to sound like anything in theory, if the proper algorithm is applied. The problem is, they've been working on the sound of a Strat going through a Marshall for a long time. It's hard to beat the sound of a well designed tube amp, but they're beginning to learn how. Some of the new Multi-EFX boxes like the Quadraverb do an amazing job at processing a guitar. But I've found that they still need to go through a speaker to smooth out the sound. (There's additional distortion, coloration and bandwidth limiting produced by all loudspeakers)
Now for all you guys and gals who like their transistor amps and fuzz boxes, there's nothing wrong with what you do. Sometimes odd-harmonics are needed to cut through the mix. I sometimes purposefully loop a guitar track back into an overdriven channel on my board just to "dirty" it up a little. It can make a bland lead really stand out at times. But it's just a matter of taste. I really like the even-order distorted, bandwidth limited, compressed sound of a traditional tube amp for guitar.
But REproduction is a different story. I've got preamps that are rated in parts-per-million distortion. I tweak all my tape decks for the flattest response possible, and work hard to get the best signal-to-noise ratio possible. That's because I like the final sound to be as faithful to the original as possible.
The theory of relativity doesn't work right in Arkansas.
Most classical concert halls use tube amplifiers.
As someone who has worked in the sound re-inforcement business, yes tube amps sound great, audio-philes love them, but well designed transitor amps can sound great too, and are much more practical, power efficent, smaller and cooler (temperature) I'd like to see some evidence to back up your vague statement.
"Karma can only be portioned out by the cosmos." -Homer Simpson
same way you deal with tubes in amps when they burn out. simple 3-step process:
;P)
:)
1) buy new tube
2) remove old tube
3) insert new tube
entire operation takes about 30 minutes (assuming you live 10 minutes from a music store with tubes
i've got an ampeg bass head (1200 watts (!)) that i can re-tube completely in about 10 minutes total...not really that hard an operation
-dk
Dream with the feathers of angels stuffed beneath your head.
I'm a real live electrical engineer with a degree and everything. And, I listen to lots of music, mostly classical. And I have a pretty good ear -- I can often accurately identify the conductor when listening to a piece. Here goes: Properly designed transistor amps produce distortion that is below the threshold of audibility (0.1% THD). This is really easy to accomplish -- even $200 receivers routinely do it. Tubes produce very audible distortion, and they clip softly. I'm sure that it would be pretty easy to design a circuit to reproduce this distortion and the soft clipping for the fine folks who enjoy it.
Huh? They're all harmonics. Tube and certain kinds of FET (field effect transistor) based amps have a "soft limiting", so when they get close to clipping, they tend to generate even harmonics. Three of the first four even harmonics are exactly 1, 2, and 4 octaves away (2nd, 4th, and 8th harmonics), and so this form of distortion tends to be more melodic and pleasant. The 6th, 10th and so on aren't so melodic, but since the amplitude of the harmonics drops as you go to higher harmonics, you're ok.
BJT (bipolar junction transistor) based amps (and other types of solid state amps) tend to clip rather hard. No soft-limiting, they stop right at the rails. This clipping action creates a boatload of odd harmonics. These harmonics are fairly dissonant, giving the harsh sound most people complain about.
But they're all harmonics.
--JoeProgram Intellivision!
Well, there is a difference between a guitar amp and a stereo amp. For a guitar, the amp is really part of the instrument. Tube amps definately do mess with the sound, but the player desires that to get the sound they want.
For stereo use, the goal of the amp is (or should be) to reproduce with the highest fidelity possible the sound as recorded. There, while tube amps tend to be better than "cheap" solid state amps, a high end SS amp is at least as good as a high end tube amp.
I do know people, however, who prefer tubes on their stereo for whatever reason (mostly snobbery, IMHO). A lot of audiophile companies make ones with tube pre-amps and a SS final stage and/or all tubes. I haven't found these systems to sound particularly better than some high end SS amps.
How? you ask?
Easy. they state they have a switched mode power supply on board.
for those that dont know, you can step up that meager 12 volts to 5,000 volts if you wanted.
also, they state that it is a DUAL TRIODE tube.
this may very well NOT be a joke. it can be done. issues I have with this setup include noise, heat, and if the tube is socketted.. or available if it dies down the road. todays power supplies are better filtered than the supplies of yesterday, and im sure that the tube is better made, as well.
I may want one just for the hell of it, you have to admit... its pretty damned neat
Really, what kind of sound card do you have? If you are using your computer for high-end audio production or music composition and are talking about truly high-end sound cards, that statement has some merit, no commercial AC 97 codec can probably produce what you would consider "good sound".
Presuming this is not the case, its probable, unless you have in fact a very obsolete or low-quality sound card, that it in fact uses an AC 97 codec similar to those used by many onboard sound interfaces. AC 97 is just a generic standard defining an interface between the sound codec (which actually produces the sound) and the controller (which attaches it to the bus, and provides DSP and synthesis functionality is some cases). Even expensive consumer sound cards like the Creative ones and the Hercules Game Theater use codecs which are AC 97 compatible. Most of the criticism of motherboard audio either has to do with the lack of features (which given that even expensive consumer sound cards don't do hardware MIDI synthesis anymore, isn't terribly relevant except for video game players) or the poor sound quality (which doesn't have to do with the AC 97 standard per se, but low quality of individual codecs and poor electrical design. None of these things are universals, I have a notebook which uses the AC 97 codec interface of its motherboard chipset, but a Crystal codec (identical to the one used by most of the CS4630 cards like the Santa Cruz, Game Theater, etc.), and produces very nice output.
"(Man) tries to live his own life as if he were telling a story. But you have to choose: live or tell." --Sartre
What is AOpen thinking? I have a few comments...
First. The audiophile market is a small and
discriminating bunch.
Second. If they intended to capture a
semi-professional audio recording market... they
would have been better off teaming up with
Apogee or Digidesign for a high quality D/A - A/D
A poster mentioned odd order harmonics causing a
"harsh" tonality; more accurately, the odd order
harmonics cause ear fatigue. An instrument that
produces odd order harmonics is a clarinet.
Don't mod me down because I post anonymously...
I rather like my privacy.
It's lower down on the page.
The tube is a dual triode, basically two tubes in the same package. It's got one or two cathodes, likely a common heater filament, two grids and two plates. The input signals go to the grids and the output signals are taken from the plates. Common cathodes would be fine, they'd both be connected to the same supply anyway. A common filament is an advantage, because it ensures the cathode(s) get the same heat, since thermodynamics plays a significant role in tube operation.
Answer your question?
--Blair
"Reading is fundamental."
So how do they get stereo out of a single tube?
Well, Most likely it would be a Dual Triode tube such as a 12AX7.
Dual Triode tubes are basically 2 tubes in one envelope.
From the looks of the photo, It uses a 9pin octal socket, which means the tube is easily replacable to your favorate, and also, most 9pin tubes just happen to be dual triodes. Hint Hint.
While it may not be standard practice to use a single tube for stereo operation, its easily accoplished with non-balanaced audio.
-Una
It goes without saying that tube-favoring audiophiles will use external devices for playing music. However, the tube amp is still be desireable for system beep tones.
at HardOCP
If you water cooled the tube, it would stop working. The tube contains a heating element that heats it up so it will function.
- Eric, InvisibleRobot.com
Two notes:
1) many line level tube circuits do not pass through trannies. There are many reasons tube circuits do not clip "hard", but the most common one is that tubes are low gain devices, operated with low (or no) negative feedback. It is NFB that "squares up" the clipping, producing the high order (nasty) harmonics.
2) I couldn't get to the site, but the most common tubes are dual triodes, which is quite sufficient for a stereo buffer.
You can design a solid-state amplifier that has exactly the same distortion and non-linearities of tube amps (but why?) -- that's not good enough for golden-ear audiophiles though. They'd rather listen to their "Test LP" on their custom turntables and talk about sound-stage separation and the "special warmth" added by the special green CD markers and about how analog is obviously better than digital because what if the signal changes between those digital samples? Me, I'd prefer no distorion, and in any case I'd rather spend my time and money on music, not equipment.
(There are a couple of reasons to use tubes, where solid state devices don't work very well: very high power applications, like broadcast radio and TV transmitters' final stage RF amplifiers; and microwave tubes, like klystrons and magnetrons.)
Unlimited growth == Cancer.
It's probably a dual triode...a 12AX7 or something similar. 2 sections of 3 pins each (cathode, grid, plate) plus three for the heater (center-tapped so you can run it on 6V or 12V) makes 9 pins total, which was fairly common.
(I looked for clues that this might've been an April Fool's joke, but didn't see anything to say that was the case.)
20 January 2017: the End of an Error.
umm, there are water cooled tubes, uasualy they occur in RF amps, some older FmM broadcast stations used water cooled tubes in their finals. Water cooling a tube will let it work at a higher current than it is rated for. Basically the water cooling is to keep it from getting any hotter than it is supposed to get. The water cooling doesnt take it down to 50 deg F, it keeps it at the ideal operating temperature.
-- free as in swatantryam - not soujanyam.
Head over to Head-Fi.org where all they talk about is headphone hi-fi audio stuff. (no, they don't sell them, but at least you can find out about real headphone hi-fi)
I mean, if you're that concerned about having quality analog audio output, you're not going to use the sound card integrated into that motherboard -- you'll just get way too much interference.
Hey-
Like IC's, there are usually more than one device in a single package with tubes. We're probably looking at a dual triode. Could (should) be quad triode, but I seriously doubt it.
It's never gonna sound much better than the D/A, which is probably a runofthemill 44.1k by 16bit job, which just isn't all that great, especially with only one triode per channel instead of two.
SO it's a sales gimmick. But, it's a DAMN GOOD ONE and I'd like to see more of this and I think it will succeed as it should!
More crap like this, please! Give me swing meters and magic-eyes and nixies! Bring it on!
=Rich
From the pictures on harcop, it looks like a Russian-made Sovtek 6922 (aka E88CC aka 6DJ8). Here's the specs on a 6DJ8. Basically a dual triode like the 12AX7 but somewhat different characteristics.
-- Alastair
The cathode rays.
I completely agree about the "gimmick" mobo moniker. This tube is going to provide a warm glow to the inside of the case more than it's going to affect the sound.
I also can't imagine what kind of microphonics (surrounding vibration being transmitted thru the tube and ending up as noise) you'd have here.
And although it's gratifying to see people pointing out the difference in what the tubes are "for" in a tube guitar amp and a home audio amp, there are the people coming out on the whole "pleasant distortion" thing, but then dropping it in the dust without really explaining what they mean.
So, here goes (I'm grossly simplifying to try and keep this brief):
Simply put, tubes add more distortion than transistors. However, tubes add most of their distortion in the even harmonics of a tone, whereas transistors add distortion in the odd harmonics of a tone. Why does this matter? Because the way we humans tell various instruments apart is in the amount of harmonics that the instrument produces for a particular fundamental (this is called timbre). This is why even though a flute and a guitar are both playing A440, they sound radically different. Naturally occuring musical harmonics are "even", that is, even multiples of the fundamental frequency.
So, when a tube amp reproduces the sound of a saxophone, it _is_ distorting the signal by amplifying, for example, the second, fourth, and sixth harmonics. Our brain takes these "natural" harmonics and internally boosts the level of the fundamental tone - in other words, we are psychologically reconstructing the musical note as slightly "louder" than it actually is.
In comparison, the transistor amps, while producing far less total harmonic distortion (the vaunted THD that we see in so many specs), are actually producing more "unnatural" distortion, because they are affecting the odd harmonics of a given tone, even slightly. Since these harmonics are not "naturally occuring", our ear-brain doesn't compensate for them in the same terms, so it registers as... well, kind of odd. More grain on the sound of a string. Harshness in wind instruments, etc.
In some ways, the tube/transistor battle is "pick your poison", kind of like the whole digital/analog debate. Some people argue that music should be reproduced with as little distortion as possible, so transistor/digital is the way to go. Other take the position that distortion-free sound reproduction is impossible, so if you're going to have it, might as well make it the kind that is more "natural" - tube/analog.
(Yes, I know I've trivialized lots of the debate - I'm not going to re-fight the audiophile wars here.)
In the end, it's what Sounds Better to You.
And for what it's worth, I own both tube and transistor equipment, and own a CD player and a turntable.
The pix at HardOCP include some closeups of the firebottle...turns out it's a Sovtek 6922, an industrial-grade equivalent of the 6DJ8 twin triode (the European equivalent is ECC88). Here's a page about the 6922 and friends from what sounds like an audiophoole perspective. (The historical info is interesting, though.)
20 January 2017: the End of an Error.