When AOpen demonstrated their Tube Amp audio technology at the 2002 Comdex it grabbed headlines and interest as a product no one was sure what to think of.  Most everyone agreed the board certainly looked unique (vacuum tubes are not often seen jutting out of modern computer equipment) but past that reactions varied considerably.  We’ve seen several generations of Tube Amp motherboards for Intel boards but this is AOpen’s first Tube board for the AthlonXP, so it’ll be interesting to see how their Tube Amp technology works when paired with the nForce2 chipset.

The AK79G Tube is built on NVIDIA’s nForce2-G chipset (meaning it offers integrated graphics) and uses the MCP-T southbridge without NVIDIA’s sound solution.  A Realtek ALC650 chip provides sound (we’ll discuss the ramifications of this later in the review).  Let’s take a look at the board itself, pictured below:

Physical Description:

The upper three-quarters of the board are standard for a modern motherboard, with the bottom quarter occupied by the vacuum tube socket and its accompanying parts.  Since there are two very different types of technology on the board we’ll deal with the standard motherboard components first.

The CPU socket is oriented vertically (rather than horizontally which can make it easier to work with) and the area around the socket itself is clear and unobstructed.  The ATX power plug is located on the right-hand side of the board close to the edge which makes it much easier to route power cabling.  The three DIMM sockets are a fair distance from the CPU to allow for adequate ventilation although they are, unfortunately, very crowded by the AGP slot.

The IDE ports themselves are near the bottom of the “standard” portion of the motherboard and are directly across from the PCI slots.  Space is obviously at a premium on a board like this but AOpen has still managed to outfit the board with an AGP slot and three PCI slots.  Considering the integrated nature of the board (and the fact that there’s no reason to buy it if you don’t use the integrated sound) you’ve got a lot of options with what to use your PCI slots for. 

The backplate is standard for an integrated video motherboard, with one parallel port, one serial port, 4 USB connectors, and an Ethernet jack (plus the integrated video connector itself).  Not much to write home about on the standard portion of the board?it’s well-built and has a high-quality appearance, but it’s fairly standard, especially for AOpen.

Tube Amp:

 AOpen’s Tube Amp assembly on the AK79G looks much like the first iteration of the technology did on the AX4B-533 Tube, but AOpen has made several changes to the overall audio system, some of which we’ve detailed below.

According to AOpen both the headphone jack and SPDIF ports were eliminated to improve frequency response and sound clarity.  Additional capacitor circuitry and layout options were all implemented to create “cleaner and brighter treble without edginess and grain, sweet / fluid midranges, and a tight bass.” (Somewhat paraphrased to clarify issues arising from translation).  The board also incorporates capacitors and resistors with a lower tolerance range for accurate music playback.  I’m not going to pretend to be an audio technician and fully understand the design principles behind the Tube Amp motherboard; the central (and most important) question we will evaluate here is whether or not the board has a different / better sound than a standard AC97 codec and whether or not its worth the money.

next > next >

---

• Tube Audio (0 of 2)
• Test, Conc. (0 of 2)