Almost all receivers convert the analog input to digital and then use their built in DAC chips to convert back to analog for output. Putting a DAC between the PC and receiver only serves to degrade the signal.
Its an entirely different thing to output from a standalone DAC directly to amps, but that doesn't sound like what you are going to do.
Yes! This is what you have to look into. Some receivers and standalone preamps with dacs do have the ability to bypass the dac or have "pure" analogue inputs which amounts to the same thing.
Whether you need one or not is something else again. Not wanting to get into any debate about what the guy from Schitt says as I couldn't find in that thread what he is referring to about HDMI he just says look into it ... be interesting for him to elaborate on a statement like that! HDMI can carry a bunch of channels, which some people need with there systems. You could create an HDMI zone for muti-channel and a SPDIF zone for audio maybe. I don't need/want multi-channel for music personally so never thought about it. Both coax and toslink have advantages and maybe disadvantages to each depending. Other than replacing the receiver, ff you can't bypass, then don't buy a stand alone DAC.
I don't understand the extra 6 "analogue" feet you guys are talking about though. When you say analogue I'm taking that you mean from the external DAC to the receiver? Or are you talking digital (which I believe what the Schitt guy was talking about. I'm not a fan about long analogue interconnects ... I use 1 meter or less, other wise go balanced for longer lengths if the amp/dac allows it. Not many external dacs I know of have HDMI inputs, I suppose they exist?
Will an external sound better ? (if the OP can bypass the DAC, that is) It can certainly sound
different. You could
not notice the difference at all, too. Can one hear the difference between linear phase filters, and a steep filter? (Even on the cambridge dac magic which I got off of ebay for 150 bucks they have choices of "filters") ... sometimes, sure, not always. So sure "digital is digital", you get your "bit perfect" (notice the quotes) signal to the dac wherever it may be, then during the conversion/once the signal is in analogue a bunch of stuff can happen. Whether your ear can perceive it or not is something else again!
I have used three Dacs on my system a Schitt bifrost uber, a PSAudio NuWave, and a the cambrige dac. I have one I prefer, its not the cheapest of the 3, but its not the most expensive either .. but Im' not tellin'
Actually they all sound pretty good!
You are paying for better power supplies, different "clocking", different sampling approaches, better shielding maybe .... the DAC chip itself is not an expensive affair, its a combination of things.
Beware of expectation bias .. if you plug in an expensive dac and right away you start marvelling at the depth of the soundstage, well I'd be careful to do some blind tests making sure that the volume level is exactly the same before plunking down any serious money.
RFI can affect certain set-ups, btw. So can plugging in your stereo to the same plug as your big double door refrigerator. Do you need to spend gobs on a "power purifier" .. euh I'd try a different plug first personally. A friend bought a "kit" dac, that had exactly the same components as a Naim dac ... sounds great for 1800 dollars less and some soldering experience. So long story ... test a new dac first on your equipment if you can.