I have been doing this computer music server thing for many years now and out of windows, linux and Apple, the apple mini is by far the best, and can be taken up several notches with the Mach2 mods, external FW storage (unless the dac is FW, then you should use usb or thunderbolt storage). I use puremusic myself but will try Amarra soon, though PM still seems to be the most stable of the two.
Tim R. -- bits are not bits even though they are supposed to be, and yes, extra processing inside the machine does effect sound quality negatively and your assertionss about jitter as well as many other things seem to be based on heresay rather than real world experience, and any c ompetent digital systems engineer will tell you that it is impossible to eliminate jitter, never mind that there are different kinds of jitter, some of which are inaudible and others of which, even in small amunts are very audible.
And no, it's not the codecs that are creating the problem, though it may in part be one part of the puzzle, but electrical noise, power suplies, etc. are critical in digital audio, which is no9t the same as digital data transmission.
You say you never could afford a mini and thus I'm assuming you've never played with one, tried different settings, software, dacs, etc. with it, but the mac mini -- not a macbook, Pro, iMac or whatever, is anything near the audio performance of the mini, and neither is a stripped down single board linux computer or windows with XP or Vista -- though some are getting results close to or equal to the mini with some combinations of win7, playback software and dacs. So again, your assertion that the mini would, or should be the worst platform is completely unfounded and just plain wrong.
And before you ask, aside ffrom experimexperimenting with probably 25 different dacs, 45 or 6 computer platforms, various connections from spdif to usb to firewire, and many different software solutions, I am an EE/CE by training and did my graduate work in computer and cognitive science, so my background, aside from my 40 years of audio experience is earned, and I'm still elearning every day ss it seems the rest of the world is as well, especially when it comes to digital audio. And no, I absolutely do not it all, in fact I consider myself still pretty green in many ways, experience aside.
Now... to the original OP, a very good place to start with a mac mini is with a stock machine -- the most basic 2.3 ghz 2011 or a 2010 is just fine. Max out the memory to 8gb -- cheap and very much worth it (but don't buy the memory from Apple, buy it and install it yourself -- I'm totally blind and did it in under 2 minutes), buy a third party SSD of 40 to 60 gb (vertex and Crucial are good choices), turn off a bunch of unnecessary features and services (there are many onlie guides on what and how to do this), and then assuming you would be using a usb to spdif converter or usb dac, get something like the 1 tb Oyen Digital MiniPro FW800 portable drive for music storage (or something similar that uses the Oxford fw chipset), rip tunes to AIFF using XLD -- even better than iTunes with error correction enabled, but a PITA to setup for the first time). Then pick a software package you like -- Pure Music, Amarra, iTunes with BitPerf.app, Decibel, Audirvana or the Plus version, and have at it. Also try to turn off as many unneeded interfaces as possible -- ir receiver, ethernet if you don't need a network connection, blue tooth for sure, and wireless lan if also not needed, and experiment with the polarity of the power cord for the sound you want -- in one orientation it's more warm and in the other, more bright.
I use mine with a wired usb keyboard and a headphone extension cable so I can use the speech system in macs -- VoiceOver) to navigate my way arund the machine, but PureMusic also lets you use the iTunes remottte app on an iPhone/iPad/iPod touch if you so desire, but you will havve to have either the ethernet or wireless enabled for that to work.
That should get you going, and will give you sonics equal to or better than some veryhigh-end CDPs, and in fact, my experience has been that an accurately ripped CD, played from memory through a good dac will sound noticeably better than extreme CD players. I used to own an Audio Aero Capitole 24/192 Mk.II SE and the information that I can get out of a standard redbook cd with my mac mini rig isfar superior -- in fact, most people can hardly believe how much information there really is on a standard 16/44.1 CD.
Hope this helps -- this is what I use in 2 of my 3 systems, thought the reference system does use a DC modified Mach2 server with a Pi battery buss, which BTW, just takes the whole thing into a whole new realm, and this week I'll add dc power to the external firewire drive (another large improvement) and a specially built firewire cable with the power legs removed -- again, isolating the computer noise from the storage subsystem and dac as much as possible. Admittedly this is a system that is a bit oveer the top but it is far better than any digital I've heard anywhere, and I've heard many of the best of the best as I have some local friends who are super high end dealers.
Good luck, and yes, I whole heartedly recommend the mac mini over pretty mucch anything else at this point.
Also apologize for the myriad typos -- my keyboard is getting old and my screen reader is not letting me review my writing.
-- Jim
