The Package

ASUS decided to jump on the 7.1 wagon with the STX II, and it is a great option for those home theater aficionados out there. The 7.1 outputs are on a separate board that uses a floppy-disk-sized, flat cable.


The cable is long enough to give you a few options in regards to the card's internal placement.


ASUS stepped the bundle up with the STX II. You get a selection of MUSES op-amps and pliers, which makes it easy to swap back and forth. Op-amp rolling creates subtle differences in the sound signature as performance characteristics remain the same overall.

Closer Examination

The card is just as large as the original STX and comes with a lot of its components. The real upgrade is the new STX II's upgraded clock, which should lower jitter compared to the STX. Also new with the STX II is the inclusion of the Muses op-amps, which quite a few high-end devices right now use.


The back panel's layout hasn't changed from the original STX's. The standard connectivity includes two 1/4" ports, which nicely shows that this card is geared toward the enthusiast as it is the default jack-type for most high-end headphones. The left/right outputs are RCA jacks, which is brilliant if you want to use active monitors.


ASUS also provides a proper converter should you want to use the card with a regular mini-jack-terminated 2.1 system.


As you would expected on a premium sound card, the caps used are of high quality.


Like its predecessor, the STX II requires a molex connector for power.


The MUSES op-amps are gaining ground in ASUS products, and there is a reason for that. These op-amps provide a somewhat smoother and warmer sound many people prefer.


Like the old STX, the STX II uses a PCIe 1x port.


ASUS stuck with the TPA6120A2 headphone amplifier chip. While undoubtedly one of the most competent chips on the market, its one major flaw is the output impedance in its stock configuration.