Introduction

It has been a while since ASUS's great debut into the world of high-end sound cards with their release of the first ST. Various versions have popped up since, including the well-performing PCIe-based STX for many audiophiles with newer motherboards. The STX unfortunately had an inferior clock generator which made it slightly more susceptible to jitter than its PCI counterpart, the ST. ASUS remedied the issue with the STX II. There is a new and improved clock on board, and the outputs have multiplied since the STX II is a full 7.1-capable design due to an add-on board. The headphone amplifier is still the Texas Instruments (TI) manufactured TPA6120A2, by far one of the most capable chips around. Its only issue is its quite high output impedance of 10 Ohms, which makes it less ideal for low-impedance headphones. While other manufacturers have managed to reduce output impedance, ASUS sticks with the standard 10 Ohms which TI recommends for stability reasons.

Specifications

• 124dB SNR
• TCXO clock source
• TI TPA6120A2 headphone amplifier
• Muses 8920/8820 and LME49720 op-amps included
• TI PCM1792 DAC