Some basic computer audio questions


I'm running a Mid-2015 5K iMac with file player software. I'd like to hook up the computer to my full-sized stereo. The only direct out I know of is the headphone jack, which would mean a 3.5mm minijack to male RCA cable. 

Questions:

1. When people were using Mac Minis, is this how they connected to their audio equipment, or was it USB out to a d/a converter?

2. With the 3.5mm to RCA cable: are there any truly high quality examples of these being made? Most are included accessories or $2 cables. Even a few at $50+ look like repackaged cheap stuff. What's the maximum length a cable like this can go to?

3. I might move files to a mid-2012 Mac Pro tower. Is there any difference in sound between a SATA SSD and  blade PCIE SSD?

Thanks in advance!


mcrib
Hi mcrib
My experience
1) Used USB out to an external dac— SQ not just "better" but in another dimension altogether2) No idea, but you could have one made inexpensively using aftermarket wire 3) No idea:) I doubt the difference (if any) is significant, compared to possible improvements elsewhere in the chain!
Regards
I have a late 2015 iMac and the headphone jack doubles as a mini-optical digital output. Not sure but I would guess it's the same for your Mac since I think all iMacs had that feature during that time period.

For analog output you use a stereo-mini cable but for digital output you use a mini-Toslink to Toslink cable or a Toslink cable with a Toslink to Toslink-mini adapter.

The optical cable can go directly to a DAC with Toslink input. I don't know if that's preferable to USB output but it works extremely well for me. It's not necessary in using the optical output but I have a Wyred 4 Sound Remedy Reclocker between the iMac and a Pro-Ject Pre Box S2 Digital DAC to reduce the jitter that's inherent in most optical outputs. Using the digital output will certainly give you much better audio than the analog output.
When I set up my system a few years ago the USB digital output was considered to have more inherent noise and jitter than an optical or coax output and most DACs didn't have USB input. Most DACs now do have USB input, including mine, but this works so well I haven't bothered to experiment.
Alternatively try a dedicated audio streamer like Bluesound Node 2i and see if that provides audible improvements in your audio system. 
It’s available online and comes with 30 days return policy. 
There are decent, relatively inexpensive DACs out there with both USB and optical inputs, Topping and SMSL are two of the names that are recommended often.
McRib, when I had a MacMini audio setup, I usb connected to a Dac (from the Mini) then to my integrated amp. I used a headless set up so I could view the library on an iPad. Now that I have gone to a one box dedicated streamer-dac I'm getting better sound. I imagine you could configure this way with a Laptop but those devices are pretty noisy.
Don’t know the specific digital out on that device but key to best sound is digital out to good external DAC of your choice.
If you want something portable Chord Mojo can function as a straight up DAC plus it is an awesome headphone amp. I go lightning digital connection out to it from iPhones and tablets and use Mogami analog stereo mini to dual rca phono plugs out into my preamp aux or any line level input and sound is to die for.