Electronics Overview
An electronics overview
In this section we are going to take a closer look at the electronic components used on this soundcard and see if we can decipher where this card gets it sound quality from. Grab a coffee and prepare to delve into the world of Essence STX
DSP(AV100)
There is really not much information about this chip to be found.
This chip is a high definition 24 bit 192 kHz audio controller offering routing capabilities and Dolby audio routines to the cards designers. We can call it the little brother to the AV200 seen on other Xonar cards.
PCI-E to PCI Bridge Chip PEX 8112
Many love the fact that the new crops of cards from ASUS have been PCI-E, these new cards to use those tiny white slots which seem to go unused on many motherboards.
With more and more motherboards migrating to PCI-E, many motherboards are coming with more of these interfaces and less of the older PCI interfaces.
The bridging chip provides signal translation features which allow the Xonar designers to connect the AV100 chipset to the to the PCI-E bus. This chip would be in a forward bridge mode allowing the PCI card to connect to a PCI-E interface. Reverse bridging mode allows PCI-E cards to connect to the PCI interface.
ADC(CS5381)
The Essence STX sports a differential input Cirrus logic CS5381 Analog to digital Converter for your analog input requirements.
Offering a maximum dynamic range of 120dB and THD+n ratings of -110 and is compatible with all sampling rates up to 24/192kHz.
To note, The Essence STX has analog input only and no S/Pdif digital input.
DAC (PCM1792A)
The Digital to Analog Converter (DAC) on the Xonar Essence STX is the Texas Instruments PCM1792A Chip. T
his DAC chip is a stereo module which supports up to 24/192 KHz and has very impressive audio measurements. Offering 127 dB (2 V rms, Stereo) THD+N: 0.0004% This DAC has Differential Current Output: 7.8 mA p-p.
We will speak about this current output a bit more in the Opamp section. Below is the block diagram of the Digital to Analog converter only.
