The Taiwan based motherboard manufacturer A Open, division of Acer Group, appear with interesting gimmick when it introduced world's first PC motherboard with a vacuum tube based audio amplifier the A Open AX4B-533 Tube. The motherboard was supported on Intel 845E chipset, and utilizes a Realtek ALC650 AC'97 audio codec chip. Firstly, many PC users surprised that showed late. Why a vacuum tube? A Open engineers pointed out that serious audiophiles have keep on to make use of vacuum-tube amplifiers because of their rich sound. They felt that audiophiles would pay a best cost for same technology in sound circuitry of a PC. A Open utilized the following design features to carry vacuum tube into twenty-first century:

• A switching mode power supply to give sufficient tube power. Tubes fell out of favor in late 1950s because they need extra power than transistors and integrated circuits.

• A dual-triode. This design has one tube with two front stereo channels and is modeled after design utilized by classic pre-amp circuits, which can also allow input from standard sound cards.

• Frequency isolation wall (FIW) noise reduction. This protects tube circuitry from normal EFI/RFI interference inside PC.

• High denote time between failure plan for motherboard and tube circuitry.

The extra circuitry utilized by AX4B-533 Tube made it one of most costly motherboards using 845E chipset. Though, it has got rave from many PC publications and users for audio quality, performance, and snob appeal of having first motherboard on block.

The AX4B-533 Tube's audio feature is optimized for classical and jazz music listening. A Open has now out extra vacuum-tube-based motherboards the AX4GE Tube and AX4PE Tube for Pentium 4 processors and AK79G Tube for Athlon XP processors. These motherboards are optimized for rock and pop music because of a little revised tube and amplifier design.