an offhand inaccurate take:
The whole buzz about upsampling etc, came about in the early dac wars re filtering, noise, etc. long story.
what really happened is that when sample rates went up the cost of making dacs spiraled out of control due to some issues in complexity or difficulty in manufacturing on a chip.
the single bit dacs (and associated variants) came along as $10--5-3 chips and the manufacturers were saved! digital for everyone, and with great press! look at those numbers on paper, and as expressed on an oscilloscope and measuring gear! wow!
and the audio press had nothing to review, unless it was inclusive of the new cheap chips.
and digital descended into mediocrity and costs vs quality vs penetration vs small lot manufacturing impossibilities and so on and so on..
and now we emerge at the other end of this digital desert, that lasted some near 20 years....with some R2R dacs finally coming back, ones that have the high sample rate capacities.
the usual: the market could only respond to the billion chip level, if it was to do what it was meant to do re overall markets and whatnot.
thus mediocrity in digital became king and we were forced to eat it. No options.
Options are back, and the old becomes new, and so on.
And finally, audiophiles get what they wanted, a maximum quality of digital reproduction in a high sample rate R2R DAC. Not a chip (as they could not effectively make and sell such chips and be in business, or even make them, period-technologically near imposible), but some new designs used programmable large scale chips as the core of their encoded (hard programming) and thus decoding scenarios (via said programmed chips).
Then... the true R2R types, the ones with large discrete arrays of resistors and the like.
The problem was the hole of time and money in the middle of the given time period, the desert time. The 20 years with numbers and spec gains only, just a repeated cycle of tiny incremental sound quality gains of a dubious nature.
Technology (and thinking) advanced... and we finally got to the point where we could actually make discrete resistor ladder type dacs at high sample rate and high bit rate capacities and make them for a few hundred dollars. Which catapults any inclusive unit (audio item) into the multi kilobuck range at a minimum, but this also works for audiophiles as this is the ’normal’ range of pricing of such high quality gear.
I’m talking about not a $3 chip in a $500 CD player, but a $175-250 ’chip’, or discrete component DAC system inside a $5k DAC. Normally the $500 cd player has a whole bunch of other chips and components that support and deal with the $5 DAC chip, and the high grade R2R DAC is the same.
It’s just that the one-bit $5 DAC chip part is replaced with a large array and circuit that is physically, on the board, 20-50 times bigger in area taken up on said board, and encompasses a large amount of discrete and/or chip based parts. This, besides all the rest of the normal support chips and circuitry for a overall DAC or digital player unit.
Costs went through the roof for the actual DAC part of the given hifi item..and will NOT be going down (by much), but at least the high quality DAC could finally be made and sold to people.
