I found this on Github. I followed the instructions, removing the HiFace and Young drivers, and my HiFace works.
This may have been posted elsewhere on AC, but I didn't find any fixes on the site and apologize if this is a repost.
Although the HiFace sounds as good as before, based upon my audio memory, I compared both of my HiFaces, the original and the JK Ver. I, and the Yellowtec PUC2 that I purchased in the interim is vastly superior in terms of blackness, soundstage, and just plain sound quality. I am thinking of purchasing a Yulong DA8 if there is another MassDrop group buy, @ about $950.00, or the upcoming Pulse, by the Divinci designers, @$299.99.
sudo rm -rf /System/Library/Extensions/Hiface.kext
sudo pkgutil --forget com.m2tech.driver
sudo touch /System/Library/Extensions
# Download and install the Northstar DAC async driver (http://www.northstar.it/drivers/Mavericks_10.9/Northstar1055r4_192Khz.dmg) via http://www.audiocircle.com/index.php?topic=120790.msg1287303#msg1287303
sudo sed -i "" "s/900/37643/g" /System/Library/Extensions/async192.kext/Contents/Info.plist
sudo kextload -b 'com.async.driver.async192'
# Restart system
# Driver should show up as "Young Async USB 44.1Khz-384Khz": http://i.imgur.com/RIIUn0A.png
# If you want to change the device name to something more appropriate, edit /System/Library/Extensions/async192.kext/Contents/Info.plist and look for "<string>Young Async USB 44.1Khz-384Khz</string>"
# Enjoy!
