PLEASE, DO NOT BELIEVE OP This is the Sound Science forum: just test this for yourself with your own gear and come back to us with your data. Related threads: What's Wrong with the Hi-Fi Scene?: A 700$ NAD Integrated Amp Is Indiscernible from a +20.000$ Mark Levinson Preamp & Dual Monaural Power Amplifier https://www.head-fi.org/threads/wha...-preamp-dual-monaural-power-amplifier.877362/ ABX test: Sound Blaster X-Fi Xtreme Soundcard vs. Fiio X1 DAP. Indiscernible from each other. https://www.head-fi.org/threads/abx...-x1-dap-indiscernible-from-each-other.878783/ Today: Asus Essence STX II https://www.asus.com/us/Sound-Cards/Essence_STX_II/ vs. Sound Blaster X-Fi Xtreme Audio PCI-e http://support.creative.com/Products/ProductDetails.aspx?prodID=15855&prodName=Sound Blaster X-Fi Xtreme Audio http://www.guru3d.com/articles_pages/sound_blaster_x_fi_xtreme_audio_pcie,1.html Ok, so I finally received my Asus Essence STX II via Amazon. My gear: Integrated Amplifier: NAD C370 This amp was reviewed by Stereophile here: NAD C370 Integrated Amplifier Chip Stern | Jan 4, 2002 https://www.stereophile.com/integratedamps/633/index.html Also featured at What Hifi: NAD C370 - The best stereo amplifiers of the 21st century https://www.whathifi.com/features/best-stereo-amplifiers-21st-century Speakers: B&W 602 S3 That Was Then… B&W 602 S3 review https://www.whathifi.com/features/was-then-bw-602-s3-review My headphones: Etymotic Research ER4XR: $349 via Amazon https://www.etymotic.com/consumer/earphones/er4-new.html After matching loudness levels with a sine wave AND with a testing track, AND after properly syncing the track playing on the soundcard with the track playing on the X1 (within less than a second of difference between them) and after connecting my headphones to the headphone output in the NAD C370: - I was considering the purchase of either a DAC+Headphones Amplifier such as the Chord Mojo ( https://chordelectronics.co.uk/product/mojo/ ) *OR* the purchase of a DAC/AMP & DAP such as the Teac HA-P90 SD ( http://www.teac.com/product/ha-p90sd/ *OR* the purchase of a soundcard such as the Asus Essence STX II. ( https://www.asus.com/Sound-Cards/Essence_STX_II_71/ ) But before that I wanted to make another small test. I connect the Soundblaster X-Fi Xtreme Soundcard to one free slot in my motherboard AND to the CD level input in my C370 amp. I connect the Asus Essence STX II Soundcard to another free slot AND to the AUX level input in my C370 amp. I match the loudness on both as best as I can playing a sine wave first and some testing tracks then. Then I can freely and easyly switch between one channel and the other, without transition or clicks or any kind of noise. I use the following tracks: Limehouse Blues - Arne Domnérus, George Ridel - Jazz at the Pawnshop Rebecca Pidgeon - Spanish Harlem - The Raven Time - Pink Floyd - Dark Side of the Moon Right Off - Miles Davis - A tribute to Jack Johnson Bruckner Symphony nº 4 - I - Bewegt, nicht zu schnell Chameleon - Herbie Hancock - Head Hunters Thinking of a Place - The War on Drugs - A Deeper Understanding Blue Train - John Coltrane - Blue Train The Sidewinder - Lee Morgan - The Best of Lee Morgan I ask a friend to switch between the Soundblaster X-Fi Xtreme and the Asus Essence STX II for me with my eyes closed. I test this with the B&W 602 S3 speakers *AND* with my Etymotic ER4XR IEMs. Result #1: I cannot discern whatsoever between them. Neither can him. This time I ask some other members of my family and the result is THE SAME: *NOBODY* of us can discern between one and the other. Result #2: I am going to return the Asus soundcard and I will enjoy my music with a $5 soundcard knowing that now I can LAUGH at all the so called "audiophiles" out there (and I don't mean any particular one in this forum, of course). As I said before: So... is 90% of the HI-FI market based on snake oil and in the fact that the human brain has a 3-4 seconds auditory memory at much? https://en.wikipedia.org/wiki/Echoic_memory BONUS TRACK: I BET NO ONE CAN DISCERN A $550 CHORD MOJO (...or any other DAC) in an ABX test from a $5 Soundblaster.