As far as I can work out all streamers have an on board computer and most have an inbuilt DAC. Some go further and include amplification. I know what a DAC does and I know what an amplifier does so stripping these bits away we are left with just the computer bit / renderer. There are very few bits of kit that are as minimalist as this. The only two I'm aware of are the rather pricey Cyrus Stream X2 and Moon Mind 180 Streamer. Both cost in the region of £1000, but what is one paying for? As far as I can make out all they do is fetch music files over Ethernet and output it to USB, coaxial or optical digital for connection to an external DAC. How are these expensive bits of kit any different from a £200 DIY project based on a Raspberry Pi, HiFiBerry Digi with Volumino software?