The path here is AC97 is the controller for the computer sound I\O jacks and the ALC650 is the sound card process

Don't forget the proaudio recording process ADC & DAC

Proaudio recorders like some Adats, Tascam recorder are equal
in the recording bit resolution and playback.

Realtek is a IC Designer that has proof of their quality products.

Realtek IC designs and produce excellent IC for
Computer Peripherals, Multimedia, Communications, Networks,
Telecom IC, Consumer Electronic's

Don't slam Reatek check out the history since 1987.

ALC650 Audio Codec is 18 bit adc and 20 bit dac resolution.
High performance Codec with High S/N ratio > 90 db

To the person who posted...

Oh, you have to replace the tube every 5 years or so. "I can't go out, I'm re-tubing my motherboard tonight."

I have never had a MB longer than 3 before upgrading it to the latest greatest thing. If this caches on, it will most likely be easier to get a mainboard that supports tubes and your 10GHz (Intel/AMD) processor in a few years.

Baby I want one!!
It might look silly but this is the first time they look like to cater for people who don't think Creative is pinnacle of audio technology.The Dacs could be something a bit better but who knows, the proof is in the sound .The only possible major downfall is the limited life of vacuum tubes ,there should be an option to power them down when not needed .Still any audio nut knows valves sound sweet and this a nice step forward from the usual and boring audio in PCs.

This tube is not a power amp. It is an amplifier for the pre-out stage, that's all. Big difference. The amping properties of this setup are weak enough that interference should not be a really big problem- Aopen claims to have dealt with it, anyway.

A tube-based amp with any decent power output would be far too large and heavy and hot to build into a motherboard.

perry, IMHO amplification should occur outside of the electrically noisy environment that is a modern PC, infact, you should go from something like a Midiman Audiophile 2496 > digital out > high quality DAC > valve preamp > transistor power amp

At least, that's how I'd do it.

Yes, and IIRC, our military couldn't decide whether the Soviets were using tubes because they were technologically behind the times, or because they were planning for a nuclear war. The intense pulse of electromagnetic radiation generated by a nuclear bomb will damage semiconductor devices, while tubes are largely unaffected. At the height of the Cold War, using tube electronics in your critical military infrastructure actually had some advantages...

Originally Posted by perry
Mig 25s were feared for years because of their high altitude abilities and incredible speed. They could shoot down any long range strategic bomber well before it could do any harm.

When the USA finally got their hands on one, they were shocked to learn the electronics were not transistor based, but tube based.

So at +3 Mach and 80,000 feet I would guess that tubes would have to be structurally sound. Not that these are the same tubes, but I think alot of people assume they fragile when in fact they are not.

Originally Posted by perry
This is just an AMP.

The board still uses a Realtek AC\'97 codec. If the tubes are downstream of the codec, they will be pretty useless. The quality of the DAC in the realtek chip is not great, and certainly no where near audiophile territory.

If AOpen were smart, they would have coupled these tubes with the VIA Envy24.

24/192 audio amplified through tubes would spoil people\'s ears.

So, who will be the first company to make a PCI card with tubes and a decent DAC?

Well, yes... tubes burn out. That is why they are socketed -- so that they can be easily replaced when they do.

As far as mechanical strength goes, I don't think a vacuum tube is any more delicate than some of the other components in your PC. E.g., dropping a PC based on this mobo is probably more likely to damage the hard drive than the tube.

I'd be more concerned about the elements breaking off or burning out than the glass cracking.

Vacuum tubes AREN"T weak things, and its protected in a tube casing... its about as tough to break as a glass jar. It won't break unless you drop it a fair distance, or hit it with a hammer or something.

Practical application for tubes - guitar amps, where you want some distortion.

Otherwise, hey... transistors are best.

*ducks*

Yeah, also consider that the biggest contemporary use for tubes is probably in guitar amps. They need to be able to take a fair amount of abuse, since they're gonna get taken on the road, whacked around by crazed rock stars (and their roadies), rained on, etc... :)

you could take your average Soltek tube and bounce it off a wall a few times, and it would still work fine. Most of these tubes are quite thick.

It's probably not significantly more fragile than, say, a modern hard drive. I wouldn't worry too much about it breaking... and besides, I'm sure it is socketed, so that you can replace it when it burns out!

(I still think it is one of the most bizarre motherboard product ideas I've ever seen though...)

Am I the only one to also consider the tube breaking? How strong will this thing be? And considering how ofter DIY'ers change companets, it's only a manner of time before the tube breaks.

I don't really care about the mobo much since I won't buy it, but I'm pretty surprised that AOpen would even let their engineers fiddle around with something like this. I'll bet someone had a lot of fun designing this baby.

-Yoweigh

Originally Posted by Transman88
Vacuum tubes? UGH! What\'s the marketing slogan, \"Buy an Aopen motherboard and take a step back in time to 1953?\"

Talk about another heat generating device I do NOT want in my computer case. Sheesh.

What\'s next from Aopen, a punch card reader? :)

Take a look at www.bottlehead.com if you want a nice tube preamp for cheap. This motherboard is a bad deal any way you look at it.

I suppose I should repost this.

[q]Maybe the suckiness of AC97 has been due to the poor amplifier circuitry commonly used, and not the output itself?[/q]

This would be correct. The C-Media chip actually has it's codec built into the DSP creating a single chip card. If you take a look at cards such as the GTXP, Santa Cruz, Creative Labs Live! or Audigy, and even the nForce you will find that they all have a DSP which does host processing for a series of [b]AC97 codec/b].

My understanding is this:

Shielding from external EMI and crosstalk between channels is important. You also want well regulated power control. You don't want signals sagging or spiking you want them to remain constant and steady.

For example:

http://www.headphone.com/layout.php?topicID=20&subTopicID=77

The AOpen board seems to have provided power regulation far in excess of what your garden variety mobo plus integrated AC97 codec comes with. From the given discussion though, it seems the design is limited to stereo and may have external EMI issues. Assuming that external EMI isn't a problem this might be nice from a good set of headphones.

For most though digital out to a nice receiver will probably give better sound.

I want one. Right now.

It does look like a pretty crappy tube and setup they are using, but hey, consider- at only $215 if MadMan is right, that means you get a tube powered preamp stage for only $115 over the cost of the board. That is a VERY good price for a tube powered output stage, even a crappy one. The AC97 thing really concerns me, tho- AC97 sounds like ass. Perhaps the low quality of AC97 is due to it's preamp stage being poor? Hopefully the tube is at least better.

As for sound quality- did you guys see the amp and speakers they were running this thing thru? My God, of course it sounded good. Folk with a Klipsch/Logitech/etc plastic computer speaker setup need not apply- this board is not for you.

Of course it is a marketing gimmick:

The suggested price is $215. Meaning it should sell street price for at least $30-40 more than other high-end motherboards, which would have a lot of features DIY'ers would rather have first, like RAID.

But, it is none the less a cool idea. Of course a push-pull design (which has at least two tubes per channel) is vastly superior, but no way that could fit and be powered. But I do believe AOpen's engineers have accounted for the EMI. Also, it says there that there is a line-in for hooking up a different sound source than the AC97. Read the AOpen page about it. Quite interesting.

Heh...

Have to say, having components that operate at ~100 volts just a half inch from my PCI slots makes me a little nervous! :) The big eletrolytic cap & other stuff to the right is probably the tube's B+ power supply... I imagine they're using a DC-DC up-converter running off the 12V rail.

I agree, this looks more like a gimmick than anything else. Stereo separation is probably going to suck with the dual triode design; heat is going to be an issue (with as much heat as modern CPUs and GPUs produce, do you [beall/b] want to add another major heat source to your PC?); and with all the EMI running around inside the case, I have to believe there's going to be at least [bom/b] noise pickup (the tube is sitting right out in the open, but I suppose they could add some shielding to it).

But, the sort of people that will shell out $2000 for a state-of-the-art turntable to play their old LPs will probably love it. Thing is, how many of those people also build their own PCs? Maybe a dozen? :)

If there really is much of a market for this sort of thing (which I question), It would've made a lot more sense to build an external DAC and tube-based amp that is fed off of a digital line out. That way you keep the heat from the tube out of the PC case, and isolate the analog electronics from most of the high frequency EMI generated by the rest of the components inside the computer.

Oh, boy! I wonder if the mobo's gonna get nicknamed as something like ENIAC.. :) We drove out the tubes... but now the fashion statements tell people they're 'in' again? hehe...

This is certainly the gimmick of the year. The virtures of tubes vs. solid state is still a cause for rampant debate among high end audio engineers. Each has it's strength and weaknesses dependent upon the application. In the final analysis, the design of an amplifier will influence the sound more than anything else.

At any rate, putting a tube on a mobo is just plain stupid. It should get hot enough to take skin off or melt cable insulation. Ouch! Oh, you have to replace the tube every 5 years or so. "I can't go out, I'm re-tubing my motherboard tonight."

I'd have a tendancy to agree with the "marketing gimmick" side, there are differences between the clipping and cross over distortion on a tube amp compared to a transistor, which is better will always be upto debate. However, a serious audiophile that is looking for tube outputs is gonna want something a bit extra in terms of what's pumping out the sound. Otherwise it's like putting racing slicks on a Geo Metro.

Something in me wants to buy it just for the novelty though :)

http://slashdot.org/comments.pl?sid=33604&cid=3636487 is the link to the post quoted.

Interesting quote from slashdot:

[quote]Quoth the poster:

It's common knowledge with audiophiles and professional musicians that vacuum tubes are better than solid state technologies at reproducing sound.

It's common knowledge (among audio engineers, because MOST "audiophiles and professional musicians" don't understand the electronics involved) that a vacuum tube power amplifier operated in a push-pull configuration and biased for Class A operation produces less distortion than the designs commonly used for solid-state power amps. HOWEVER, a solid-state PA operating under the same conditions will produce just as clean an output and waste just as much power and generate as much, if not MORE heat.

That being said, I read the tech specs on the board and find it a woefully inadequate attempt to cash in on the "coolness factor" alleged to apply to tube amps for audio.

The tube on the mobo is a dual triode. Since it's being fronted by a stereo sound circuit, push-pull design is out of the question. It's just a straight-up dual-channel, single-ended power amplifier. This coupled with the fact that (IIRC) most multi-section tubes are directly-heated (the filament IS the cathode instead of just a heat source), indicate that improvement in perceived audio quality will be minimal at best.

Without seeing the schematic for the amp, I can't give an opinion about it's stability, but triodes tend to be fairly susceptible to parasitic oscillations if they are operated at more than moderate power gain without HEAVY bypassing. This hefty use of capacitive filtering is what gives tube amps their reputation for "warmer sound". The fact is that a lot of the higher frequencies are bled off by the bypass capacitors.

Class A amps typically have a plate efficiency of 35 percent or less. This, coupled with the existence of the tube's filament (heater, for the Brits among us) indicate that the tube is going to produce PRODIGIOUS amounts of heat for a minimal improvement (if any) in true audio quality.

In short, I see it as a "gimmick" mobo.[/quote]

Wow, what a stupid idea.

anyone that really cares about audio quality, to the point that they want a valve preamp, is going to want to drive it with something slightly more spectacular than onboard AC'97 audio..

say, one of these http://www.midiman.net/products/m-audio/audiophile.php

Check out /. comments on why this is only a marketing gimmick
http://slashdot.org/article.pl?sid=02/06/03/1822222&mode=nested