ASUS Xonar U7 7.1 USB Sound Card Review
A Closer Look at the Xonar U7
Considering it is part of ASUS’ Xonar line of soundcards, the U7 comes in a rather low profile black cardboard container. While it is a touch low key for a Xonar product, the U7’s box is still eye catching and filled with information.
The accessories which accompany the Xonar U7 are rather simple, but that’s to be expected since ASUS was aiming for a plug and play solution which needs just one point of contact between the system and sound card. You get a large installation manual, driver CD, USB 2.0 cable, and an S/PDIF – TOSLINK adapter (which was missing from our sample). Since this model natively supports 7.1 outputs, it doesn’t require a break-out adaptor but we would have still liked to see RCA to 3.5mm adapters to improve upon the native 7.1 abilities.
The Xonar U7’s hardware is packed into a squat box black with gold accents and is deceptively small considering the number of output options being supported. It measures a mere 1” tall by 3.1” deep by 5.5” long. This firmly places it into the portable category and while too big to fit into a pocket, finding room in the typical carry-on or laptop bag should pose no issues.
On the front panel you will find a dedicated headphone 3.5mm jack, the microphone / line-in jack, and the microphone volume up & down buttons. These buttons simply send proper commands on the system’s OS rather than being hardware volume controllers.
Atop the device there are three indicator LEDs which glow a pleasing blue. They indicate whether the sound is being sent to the speakers, dedicated headphone output, or the SPDIF port. There’s also a stylish looking volume controller.
Unfortunately this wheel is software-based so it simply sends the proper commands to the OS to raise or lower the volume rather than modifying parameters within the U7 itself. Pressing down on it will also send a mute command to the OS and when pressed a second time will unmute the volume and adjust it back to its original level.
Around back we see a cramped but functionally well laid out area. There are two (red and white color coded) RCA ports which pull double duty as front channel outputs in 7.1 configurations. Next to them are three 3.5mm outputs (side, center, rear) and the SPDIF port. On the far left side is the USB 2.0 input. All in all these options are impressive given the relatively inexpensive nature of the Xonar U7.
The only potential stumbling points we see here from a features point of view is the lack of RCA adapters (don’t worry, they’re really inexpensive), and that ASUS has decided to go with a USB 2.0 interface rather than use the 3.0 standard. Luckily, RCA adapters aren’t really necessary since most connections for 7.1 will be through the SPDIF optical out port, whereas most headphone users will tap the U7’s dedicated stereo headphone amplifier port.
We understand that USB 2.0 needed to be used in an effort to broaden compatibility with older systems but it does introduce some limitations. For example, the Xonar U7 has access to just 500 miliwatts of power, whereas USB 3.0 would have offered 900mW. ASUS could have used a dual headed USB 2.0 header cable to provide additional power from older setups but decided to avoid the complexity of that route. Hence the U7 is only capable of powering 150ohm headphones compared to its internal Xonar brethren’s 600ohm abilities.
On the underside we can see that along with four small rubber feet is a small switch. This switch changes the Xonar U7 from a USB 2.0 device to the 1.1 standard, providing a much wider compatibility range. Just remember that accidentally switching this to 1.1 can cause problems with newer systems.
Taking the Xonar U7 apart we can see that the internal PCB has a fairly neat and tidy layout with almost no solder marks. Every trace is clean, which is extremely important for audio quality and consistency. This is a marked difference from may other USB DACs and soundcards we have seen which usually strive to hit a low cost rather than high quality.
Moving on to the actual internal components, we can see that ASUS has opted for a Cmedia’s 6632A as the main controller for the Xonar U7. The USB 2.0 capable 6632 is quite highly regarded and is found in many good USB 2.0 sound cards such as ASUS’ Essence 3.
On the DAC side of the equation, the dedicated headphone amp uses a single Cirrus Logic CS4398 IC, while the multi-channel speaker output uses a single Cirrus CS4362. Both are decent if not spectacular choices. Unfortunately, Xonar U7 does not make use of any physical EMI shielding besides separation on the PCB. This is not as big a deal as it is with the U7’s internal brethren since it will be outside the PC and thus subjected to a lot less EMI interference.