Performance

The ASUS U7 is for people who want readily available 5.1 surround or a better headphone output than what is usually on laptops and some desktop PCs. At only $99, the U7 is quite a bit cheaper than the Sunrise Ray DA-P1 at $200 and the O2+ODAC by JDSLabs at $249, and it has 5.1 outputs.

We hooked the U7 up to a set of in-ears to kick our tests off, giving it a good go. The U7 sounds great compared to the headphone output on a Lenovo x201 or the Realtek on our PC, sounding really good with a set of HifiMAN RE-400s. The background is totally black and the dynamics are good as well. Its sound stage is not quite as well-defined as with the Sunrise and JDSLabs DAC/Amps, but it is sufficiently close not to be a big drawback. Bass control is also good, albeit not as snappy as with the O2 or DA-P1. The gain is a bit too much with a set of really efficient in-ears, but it is a very good match for normal in-ears based on dynamic drivers, like the HifiMAN RE-400s the RHA MA350s.

Even with a set of Sennheiser PX-200 IIs, the U7 is very close to the much more expensive DAC/Amps in our test.

Going from in-ears and small supra aural headphones up to the QPAD QH-90s still leaves the U7 with power to spare, providing a very good listening experience through the headphone out. The bass is kept in check and still sounds very detailed. The control and power is not quite the same as with the two other DAP/Amps, but it is, again, very good for a USB sound card. The sound stage is better than that of the DA-P1, which is quite a feat with a USB-powered solution.

It is good for medium hard-to-drive headphones, but can't drive the Sennheiser HD650, HifiMAN HE-500, or HE-6 without massive distortions. This is to be expected from a 5V-powered device and can't, as such, be called a con in terms of performance, but it is something you have to be aware of when buying USB-powered audio products.

Using the line-out from the U7 was quite good. The two RCA plugs on the back deliver a standard line-level signal that can feed anything, with the volume dial turned all the way up. We ran it to our Sunrise Ray DA-P1 and O2 amplifier and had a very pleasant listening experience. The sound quality was almost on par with what you get from an ODAC, which costs as much as the ASUS U7 but only has one output.