Bo mạch chủ có phần tiền khuếch đại âm thanh bằng đèn điện tử

Bo mạch chủ có phần tiền khuếch đại âm thanh bằng đèn điện tử

Đây là thông tin mới cho những tube fan.

SAN JOSE, CA, June 3, 2002
-- AOpen Inc. announced today that it is introducing the world's first vacuum tube motherboard, coinciding with Intel's announcement of the Pentium® 4 845E chipset. The new AX4B-533Tube Motherboard incorporates the novel, modern-day adoption of an idea that was spawned by the invention of the electric light bulb by Thomas A. Edison back in 1879 - the vacuum tube. In taking this bold step towards audio perfection, AOpen's hybrid AX4B-533Tube unquestionably is targeted to a very exclusive niche market - passionate audiophiles and extreme gamers who are interested in building th

eir own ultimate entertaining PCs. The motherboard is also certain to appeal to retailers that desire to cater to these two eccentric groups with custom-built PCs, delivered with matching speaker systems and the latest CD and DVD playback devices.


Why The Vacuum Tube?

The first logical question anyone - analyst, journalist, technician or consumer - would likely ask, is . . . why? AOpen engineers admit that their original notion to add the unmistakable sound of tube output to a modern-day motherboard was initially a lark. "We were all together late one night, kicking around lots of crazy ideas when
I proposed it would be really cool if we could combine the warmth and depth - tonal realism, if you will - of the sound produced by an audio tube, with one of our state-of the-art motherboards" says Al Peng, product manager at AOpen America Inc., an audiophile for more than 10 years. "Laughter turned into raves a few months later when we did our first lab demo of our unique hybrid creation. The reproduced sound was absolutely amazing.







It left everyone stunned. What we realized at that moment was how the limitations of typical audio output from a PC as we knew it, had come to an end - and what we were pioneering was a way to literally combine the best of two audio worlds - old and new."




The Watts and Volts of Combining Solid-State and Tube

Some skeptics may argue that even average solid-state amplification devices are often better than the best tube devices. However, in terms of tonality - that's where solid-state working alone falls short. Since the tube output stage of the AX4B-533Tube couples the two front digital stereo output channels with tube output, music lovers of all kinds will "feel" their singer, band or orchestra seemingly come alive, while gamers will find that sound-effects become far more convincing and "to your face". A brief look at what makes a tube work provides greater perspective to the overall concept of combining tube with solid-state.

There are four principal elements in a modern vacuum tube that work together to make it function. The Filament (heater), Cathode, Grid and Anode (or plate). The filament is connected with voltage to boils the cathode, causing the cathode to emit electrons that pass through the grid and hit the Anode. Through this electron flow, the tube amplifies a small (AC) alternating current signal into a larger AC voltage, thereby amplifying it. By controlling the grid voltage, the current flow can be regulated, and create the desired electronic characteristics, while amplifying the signal (source).




Tubes may date back to well over 100 years, but the AX4B-533Tube proves that even today, tubes shape the sound of many modern bands' characteristic styles. In fact, most electric guitar and bass amplifiers are tube-based. High-end professional audio equipment also relies on the tube as a preferred amplification device. Tubes are even found in digital-to-analog conversion equipment.


Some Technical Considerations


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SWITCHING POWER
One of the more daunting challenges for AOpen engineering team in developing the AX4B-533Tube was the process of powering the tube circuitry that requires high voltage of up to 300V 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 con***ions - correct audio playback is achieved. As a result, the AX4B-533Tube performs brilliantly.


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TUBE CIRCUITRY
After careful study of many classic pre-amp circuits, AOpen decided to employ a single dual-triode (one tube with two front stereo channels) as the main amplification device. In ad***ion, by following a long path to achieve signal amplification, straightforward amplification is achieved without the use of numerous coupling devices that could add unwanted coloration to the sound of the playback output.

A separate input connector is also provided allowing users with existing sound card's output going through the tube amplification to achieve desire tube tonality. This design allows millions of users out there with their existing sound card to be working with AX4B-533Tube in tandem.




NOISE REDUCTION
One of the inherent difficulties of utilizing tubes for audio output amplification has always been the dreadful by-product of noise. AOpen solved this problem flawlessly with a method of noise reduction called the Frequency Isolation Wall
(FIW).
The FIW is strategically placed at all regions throughout the motherboard that separates each operating frequency regions such as CPU, memory, AGP and PCI where the operating frequency ranging from 133MHz, 66MHz and 33MHz. Cross talk among each regions had been reduced greatly for overall system stability as well as minimize inherit noise that may go to tube amplification circuitry.




RELIABILITY
A critical issue with any electronic device is reliability. When it comes to hybrid audio equipment, reliability plays an even greater role. The MTBF ratios for both the motherboard and the tube circuitry in the AX4B-533Tube are stellar,

with minimum 50,000 MTBF hours on the motherboard, and 35,000 MTBF hours on the tube circuitry (Tube itself will have about 4,000 to 5,000 hours, depends on operating con***ions)



COMPONENTS AND CONSTRUCTION

To ensure accurate tonal quality for music playback and to fully enhance the gaming experience, AOpen engineers meticulously selected the finest components from the world's top-rated manufacturers in designing and building the AX4B-533Tube. In ad***ion, the AX4B-533Tube
is painstakingly and patiently assembled, piece-by-piece, then fully inspected and individually tested by AOpen technicians to ensure that each motherboard meets its desired peak performance levels without hesitation.
The AX4B-533Tube Motherboard comes with latest Intel 845E chipset design and features DDR SDRAM memory channels delivering 2.1 GB/s of memory bandwidth to the processor - maximizing the full performance of the Intel Pentium®
4 processor with 533Mhz FSB offers best overall performance and longevity. It comes with a 4X AGP slots; with new ICH4, the AX4B-533Tube supports 4 ports of USB 2.0 and Ultra ATA/100 interface.
With Intel 845E chipset, AOpen's AX4B-533Tube provides a revolutionary fusion of old and new technology, producing unsurpassed PC audio output that takes full advantage of the Intel Pentium®
4 processor's capabilities.





Audio grade components are used throughout critical circuitry. By cooperating with Reliable Capacitors, high-end Rel MultiCap coupling capacitors were used. Cardas wires are also deployed strategically on the output to achieve faithful reproduction of music and sound effect.

(Fred, We need to expand this portion a
bit. Please visit www.capacitors.com
and www.cardas.com
for more information to emphasize the value we are providing to the gamers and
music lovers. Thanks)


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