PC enthusiasts will certainly be interested in the new Asus Essence STX II and STX II 7.1 PCI-Express sound cards. Key factors include 124dB signal-to-noise-ratio (SNR) clarity for line-out and 120dB for headphones with a 600 ohm-headphone amplifier included.

Precision clock is controlled by a temperature-compensated crystal oscillator (TCXO) clock source, power delivery is optimized with low-dropout (LDO) regulators and German-made WIMA capacitors deliver balanced sound.

The new series also feature additional gain control for in-ear monitor (IEM) headphones, MUSES 8920 and MUSES 8820 operational amplifiers (op-amps) and an included op-amp swap kit.

Both Essence STX II and STX II 7.1 benefit from swappable op-amp sockets and come with a swap kit that includes three additional op-amps - two Texas Instruments LME49720s and one MUSES 8820 ? that allow users to create different timbres and tonal combinations.

Exclusive to Essence STX II 7.1 is a multichannel daughterboard that delivers true 7.1-channel surround with 120dB SNR outputs. This daughterboard slides into a slot adjacent to Essence STX II 7.1.

Each channel is fully customizable with nine swappable op-amp sockets.

The cards also benefit from a software package that includes a full version of Dolby Home Theater software suite for PCs.

Asus did not provide pricing details for the new products.