Do I need a streamer?

There are means to get nice sound out of computers such as mac mini but requires much diy effort. I used three different iteration of mini's over the years, last one provided very nice sound quality, no complaints, could have lived with that one for a good many years.   

I agree that general service computer does not belong in high end streaming setup, self generated noise, lousy rendering, nothing you do post  computer will get back what's been lost in the noisy general service computer used as streamer. Stock mac mini is one thing, highly modified mini is quite another.

As good as that final mini was, my present streaming setup betters that by quite a wide margin.

My greatest issue with vast majority of off the shelf streamers is lack of processing power, forget about running HQPlayer or any intensive DSP, I bet many would surprised by what DSP can offer. Versatility of present setup allows great manipulation of digital bits, like having a number of different streamers and dacs in one system. I'd suggest custom build streamer is valid route for top flight streaming if one is up to the task.

I agree, don't write off the computer, but you need to do some research, learn how to optimize. You can pair down processes run by operating systems and power with lps, creates much lower noise floor. Computers can compete with or surpass off the shelf, requires knowledge. Can't or don't want to make the effort, get  off the shelf.

Something that always seems to get lost in streamer discussions is the idea that all streamers are computers. The dedicated streamers use computer motherboards, in some cases the exact motherboards you may find in a standard computer. SOTM makes the only dedicated audiophile motherboard I'm aware of. Then we come to the hardware used with these motherboards, processors, RAM, SSD, etc. I see nothing special being used with most dedicated streamers, most use standard stuff one finds in general service computers. As far as processors most use rather low end so as to keep noise down, more easily accomplished vs more powerful processors.  Less powerful processors don't allow much if any dsp, manipulating digital bits via dsp may result in much higher sound quality. As far as the rest of the hardware, one can do much  better than the common parts found in vast majority of dedicated streamers, enterprise level hardware with extremely low levels of latency contribute to lower levels of jitter vs the dedicated streamers.

Dedicated streamers do come with optimized operating systems, which can be replicated by the diy. Issue is diy needs to acquire the knowledge in order to maximize OS. Some dedicated streamers also have proprietary music players which may or not be superior to the Roons, Audirvanas of the world. Both proprietary OS and music players are also available to the diy, so this need not be a consideration for direction taken.

Then we come to power supplies, the better dedicated streamers do come with linear power supplies, again something available to the diy.

End result is I'd put my custom build streamer up against any off the shelf dedicated streamers out there with exception of Wadax and Taiko Extreme. All enterprise level parts, JCAT PCIe board, proprietary OS, proprietary music player available along with Roon, HQPlayer. Finally, I'd put my LPS up against any lps available at any price, over thirty years in developing this lps, first totally linear power supply ever developed for Windows based motherboards.

The point of this is don't fool yourself that dedicated off the shelf streamers are the end all of streamers. The diy or custom builds can equal or surpass sound quality of off the shelf.

But going back to OP. Yes, one does need dedicated streamer, whether diy/custom build or off the shelf. My first foray into streaming was with general service computer, my first custom mac mini way back in day easily surpassed the general service. The general service computer is noisy environment, noise takes away from resolution, resolution you can never get back once lost. Optical solutions may block noise from dac, but can't give back what's  lost in streamer. General service computer does not belong in audiophile streaming setup, one has handicapped their system at the source. I don't know why this question is continually asked with so many here attesting to the value of dedicated streamers. Yet to hear a single instance of someone contending general service superior to dedicated streamer,  speaks volumes.

@ghdprentice I've not personally done  comparisons to top line off the shelf streamers, but the group of people who built my streamer and other very similar builds  did hear and compare my exact build which at the time of comparison used HDPlex 200W ATX internal power supply combined with a number of nice external linear power supplies, so this build was last compared to Aurender W20SE, the custom build was preferred by the listeners. Information on this build, along with others and comparisons to various off the shelf streamers can be found at Audiophilestyle forum, thread is well over 700 pages at this point! This group does find the Aurender to be one of the top echelon streamers, only bettered by Wadax and Taiko Extreme.

Those exploring custom builds based on Windows motherboards have experimented with no end of hardware, optimized software, at this point have come to conclusion the best custom build can compete or surpass every off the shelf dedicated streamer with exception of Wadax and Taiko Extreme. The individual that built my streamer with the HDPlex power supply ended up purchasing Taiko, Individual I purchased streamer from also ended up purchasing same. Both have not heard this streamer with my JCAT Optimo LPS so who knows where it stands in hiearchy of dedicated streamers? I'd certainly like to do direct comparison to Aurender W20SE, undoubtedly one of the best streamers out there.

@mapman Optimized rendering via USB, I2S, coax, AES/EBU with PC requires JCAT or Pink Faun boards powered via external lps. Rendering via motherboard, even with optimized OS leaves much to be desired. Ethernet optimization effected with JCAT NetCard XE.

DIY route is certainly not for everyone. All this has been steep learning curve for me, and continues to be. The cost premium one pays for off the shelf dedicated streamers is well worth it if one doesn't want to get bogged down in technical details. There have been those moments when I regretted my choice, luckily they've passed! Plenty of more knowledgable computer guys willing and able to help has gotten me past some rocky cliffs.