This is a great USB DAC/AMP using the new ESS Sabre ES9038Pro DAC. The digital volume control also adjusts the RCA output. Also allows use of an external power supply. For more information: https://hifimediy.com/uda38pro-usb-dac-es9038pro $200 shipped in the USA with paypal. I'm also selling a Koss ESP950 system, just add $400 more for the full kit!