A mobo with a tube?

[pentium]

A while back I remember seeing an article a motherboard that used a single tube for it's audio amplifier. I can't seem to remember the brand and I can't find anything on google. Anyone know about the board I am talking about?

[willawake]

no sorry
http://www.digit-life.com/articles2/...ube/index.html
nope
http://www.neoseeker.com/Articles/Ha...aopenax4btube/

[Topcat]

Aopen AX4B-533 P4 board. I've recapped quite a few of those. A very unique board, I must say.

[stevo1210]

wow. that's something i've never seen before....

[pentium]

Thanks topcat. What kind of caps were they? Choyo?
I wonder how bad their heat output is? How much power do you suspect is needed?
Oh great, a closer look shows no real tube model number like you usually see in old tube sets.

[starfury1]

I had forgotten about that one till you mentioned it....wouldn't have remembered who made it or what model yeah valve state MB..... ok ok I know its only for audio

AOpen AX4B-533 Tube

AOpen AX4GE Tube-G moederbord review

AOpen AX4GE Tube-G another review (link) page 2 (pics there)

TubeSound Motherboards:

There are four new models of TubeSound enabled boards, the AX4GE-Tube, AX4PE-Tube, AX4GE Tube-G, and the AX4PE Tube-G. The PE and GE suffixes denote which version of the Intel 845 chipset is used; the GE variants feature Intel's 82845GE integrated graphics solution. The G suffix denotes the value version of the motherboard, without the extra Promise SATA/ATA133 chip onboard.

Page1 1 link

cheers

[PeteS in CA]

If that tube has a 100V-150V plate voltage, I'm curious how it is derived and how safety regs compliance was achieved, if it was.

[gonzo0815]

That was the exact same question which was coming to my mind after seeing the step up converter ;-)
I think they had to place a isolation shield over the bottom side to accomplish this.
May be TC can enlighten us.

[pentium]

Same here. where's a link to the mobo manual. It should tell all.

[willawake]

One of the more daunting challenges for AOpen engineering team in developing the AX4B-533 Tube was the process of powering the tube circuitry that requires high voltage of up to 100V from the power supply to properly operate the tube. By incorporating a switching mode power supply for the tube circuitry that can truly rival solid-state amplifiers, then employing a maxim 668 DC-DC voltage converter to provide ample voltage for the tube to function under optimal conditions - correct audio playback is achieved.

....

[gonzo0815]

Well, from the picture i think it is showing the inductor or converter as trough whole component.
Thus the high voltage is unprotected without any shielding
At least i would not have the balls, to let the air isolate against the case..

[marco916]

Sorry for the late post, I just joined bad caps forum today and noticed you guys were taking about the Aopen board with the vacuum tube. Actually badcaps.net replaced my caps on mine a few years ago, and still use this board today with Vista and Intel P4 3.2ghz CPU, the audio output sound is nice when using it in conjunction with a tube amp. That’s when you really here the sonics. Here's some pics of my board after finishing it up in the case.
http://picasaweb.google.com/ty.monro...19049134339122

[pentium]

Was there an older replacement for the tube?
I have a rubbermaid tub filled with tubes.

[marco916]

The MB uses the Russian Sovtek 6922 tube which is in use today with many vacuum tube audio gear. If you have a rubbermaid tub full of these, I would suggest to eBay half of them, and save the rest for another 20, 30 years when they become very rare to buy. I'm sure you will get a pretty Canadian Penny for them.

[bgavin]

[hijack]
Hey Marco, I see you are in Sacramento. I'm in Orangevale.
[/hijack]

[marco916]

Hi there bgavin, I'm actually in Antelope, but nobody knows where thats at. (:

[drchaos67]

I just finished recapping my AX4B-533 Tube motherboard today. All the electrolytics 1000uf and larger were bulging and most of them had leaked. I have been using this board for years now and recently it began to require two boots to be stable. From day one, if the room temperature was below 70F, the sound drivers would not initialize. It will be this fall before I discover whether or not recapping solved this particular problem. There have been a few other issues such as the chipset heatskink falling off after one of the (soldered in) U-shaped pieces of wire holding the spring clip in place mysteriously worked loose from the board. According to a tube audio expert I know, the tube circuit has a cathode-follower arrangement, implying the designers did not wish to operate the tube toward the limits of its gain, so the tube sound effect is nice but relatively mild. Unless you know what you are listening for (and have a nice audio system to play it through) you will not notice it. Also, I found the board was mediocre at best in the capacity of <<recording>> audio, so I still use handmade custom TI C32 DSP boards with external A/D - D/A pods (on a P3-800 running Win95OSR2! Hey, don't laugh - with no bloat and no DRM it's faster than a lot of modern multi core setups running Win7!) for recording. Anyhow, to the topic at hand - recapping the AX4B-533 Tube: All of the "Leylon" caps, black and gold on the plastic sleeves, were bad. There were (5) 2200uf 16V at positions TC7,TC11,TC13,TC42 and TC43. (3) 1500uf 6.3V at positions TC5,TC16 and TC29. (5) 1000uf 6.3V at positions TC8,TC26,TC30,TC32 and TC33. The worst one was the 2200uf 16V between the 7806 regulator and the tube. Everything seems to be working correctly after the job but a little time will tell - the side cover isn't going on for a few more days at least!

[Th3_uN1Qu3]

Lelon are a known bad brand. It's a shame that they used bad caps on such a nice board. As for recording - it's a regular AC'97 codec after all, no wonder it gets beaten by an external D/A converter.