ASUS Xonar U7

JasonP

There will be a lot more discussion on my part and some measurements (loopback mostly) of this "highly regarded' usb sound card. I picked it up because I need a low noise floor DAC/ADC for equipment testing and it seems to have that. On the other hand I just tested it out with headphones and it sounds like lame garbage. I'm assuming that is the amplifier used for the headphone out, since the Cirrus Logic CS4398 has found its way into many high-end devices (Marantz CD players for instance), a 120db SNR 32-bit DAC. Right now I'd rank it like so of the headphone devices I have here:

1) Fiio X1 (PCM1492 DAC)
2) Lumia 640 LTE phone (unknown DAC)
3) Xonar U7

I'll report more after more testing.

JasonP

Alright, I rigged up its line level outs to my Fiio E6 headphone amplifier. Wow, ok there we go. So it is just that internal headphone amp is craptastic. Well now onto more testing.

jr@mac

Good to "hear"!

JasonP

INTRODUCTION
Alright, now onto some testing and analysis. First I'm not going to spend much time breaking down the hardware itself, you can find that information online already. A great review is available on the TechPowerUp forum, here: https://www.techpowerup.com/forums/threads/asus-xonar-u7-usb-soundcard-review.209326/ In a nutshell the device is comprised by:

• A C-Media 6632A Usb audio interface
• a Cirrus Logic CS4398-CZZ DAC for stereo output
• a Cirrus Logic CS5361-KZZ ADC for stereo input. The ADC allows 24 bit sampling at up to 192kz, and promises 114 DR/SNR

SETUP
For this intial loopback test I simply connected the output back to the input with a high quality cable and set the levels at: -1db, -3db, and -10db. I could not get RMAA to accept a -20db input, as it complained the signal level was too low. Here are the results:

RESULTS

Looking above we can see the device delivers as promised. 112 db DR/SNR on -1db level and -3db level, increasing to just over 113db DR/SNR on -10db. The final measurement, the cleanest result, was with the output set at 50% and the input full.

The Asus Xonar U7 comes out of the gate scoring well on test one.After I rig up some testing dongles, we'll see how it does on headphone output and driving loads.