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A-open’s new motherboard with vacuum tube preamp


2002-02-18 7:53 pm
An engineer at the well-known motherboard manufacture a-open has built a motherboard incorporating onboard audio with a vacuum tube pre-amp stage. The board also uses ELNA caps, Cardas wire, REL Mulitcap Capacitor and VISHAY resistors. The board comes with a sock Sovtek 9622.

More information can be found at http://www.aopen.com/products/mb/ax4b-533tube.htm The board is called the AX4B-533 Tube.


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As was pointed out in another thread, maybe on this board or another, the inside of a computer is a pretty "noisy" place to put an analog tube circuit. Be better just to hang the tube pre off of a FireWire (or even USB) port outside the computer box.

Nice pictures thou. Thanx. A real mix of old electronics and new.

Beats me what putting the sound through a single vacuum tube will do after the sound has already suffered the indignities of wiggling through tens of thousands of semiconductors... I think it's a bit like putting a magic power cord on your amplifier even though the power has already traversed maybe hundreds of miles of wire.

That said, I think the mobo is really cool, not from an audio point of view but simply for the sake of aesthetics.



2002-03-12 7:46 am
The engineer or engineers certainly did a great job but I have to agree the insides of computers are too noisy for that board use but maybe outside the output stage should sound better. But I think the "idea" for this design may come from the same idea of putting expensive caps in the signal path for a band-aid. Don't get me wrong I use PP, PS, and Met Poly caps too but I'm mainly interested in the price-to-performance ratio. Cheaper cap parallel with small value premiunm cap.


2002-04-12 4:41 am
AOpen motherboards has better filteration and regulation then other motherboard manufactures. AOpen uses 2000uF for the on-board power supply and other manufactures uses either 1000uF or 1500uF. With a good power supply like Turbo Cool or Enermax, the noise can be kept to a minimum.

The tube can be switch off if the user doesn't want to have it on every time they start up.