Yes, USB Audio Player Pro (UAPP) will work as well as Neutron. I am sure there are probably others also, but these are the most popular ones (that I know of).I don't have a PC and I don't have wifi right now. I live in the country and its hard to get decent wifi out here so i havent gotten wifi yet. I was planning on using the dx300 because I have a lot of music I use offline. Would usb audio player pro work like Neutron or is that a different thing?I guess I could use my phone because I have unlimited data. My phone is android so I would have to use USB and download the necessary apps. I don't know if i would like to have phone calls and text while music is playing though. I need to just try to find some decent wifi and buy a streamer.
Oh, you could use the DX300 in any manor you choose. I was just curious why not just use the DX300? It is a desktop solution in portable package, and at over 2w (using Amp12) you can power any head gear you choose easily, or with Amp13 you can also run a tube amp directly from it. But then, I am completely mobile, and don't use desktop solutions per se', so that might not be the best for your use case scenarios.
It sounds like you will be using the DX300 as a transport only, then an external DAC, and another device for the amp. Anything with either coax, BT, or USB out should work on this setup.
Are you using Amp12 or 11.2 on the DX? If you have the Amp12 card, you can go directly to the amp (and bypass the external DAC) via 4.4mm balanced (if your amp will accept that input), or if you have 11.2, and your amp has "pre-amp" you could just use the amp as an output for your phones (otherwise you would be double-amping the source).