It depends on the what transport is being used. I'm bringing my surface pro, which only has one USB output for my dac. It uses a microSD card though, which people can use their own music for. I have my own music too, but I don't know if it'll be up to everyone's tastes. Bringing a USB stick usually works for vendors/setups that have multiple usb ports. Or some people like to bring cd transports, in which you'll need to use CDs.