As a broad concept: Cheap, high-function DACs definitely exist.
For instance: Apple-produced headphone adapters for iPhones are inexpensive -- like $10 or so. And inside of that diminutive adapter is buried a whole USB DAC, with a headphone amplifier. It's so seamless and low-cost that some folks think I'm crazy when I tell them this, but they measure great and also work great. (They work great as DAC/headphone amps for PCs, too. Android, not so much: It works, but there's a bug [that will probably never be fixed] relating to volume control and low output level.)
Anyway, I identify as an audiophile. I've spent several decades playing with this stuff, sometimes well beyond the level of "serious hobby." I've made some money doing audio stuff. I've also spent some time in the studio, and in front of the stage, making things sound good.
And I'm practical. I promise you that I can wire up a high-end stereo system with metal coathangers that will sound indistinguishable from something connected using only solid silver Kynar-insulated wire that is jacketed in cloth woven by Benedictine monks from the first cutting of wool from a single virgin albino Bolivian alpaca (for "purity") that has been dyed and imbued with post-civet Kopi Luwak (for "balance"), in any correctly-controlled blind A/B/X test.
Trust your senses. And by that, I mean: If it looks like bullshit, and it smells like bullshit, and it tastes like bullshit, then spit it the fuck out. :)
For sorting inexpensive products that actually work from those that have practical issues like hum or noise: That's what Amazon reviews are for.
But there are some very nice things for sale that aren't stupid-expensive boutique items. Schiit, for example, builds their own designs in the US and charges Buick prices for them instead of Bugatti prices -- and their website shows photos of what the devices look like on the inside, too.
...anyway, ground loops are usually real. Professionally, I've encountered them most-often in residential environments when converting a customer's television into any manner of home theater. 100% of the time I've discovered this, it was because some bonehead grounded the cable TV wire or the satellite dish to some ground that was separate and distinct from the home's electrical ground -- which should never, ever happen.
The loop would show up when we introduced the first bit of gear that had a 3-prong plug into their mix of things that previously only had 2-prong plugs. Adding the AV receiver, the subwoofer, or whatever tied the electrical ground to the stupid ground and current would flow between them, producing noise.
(And USB-C is ground-referenced, so keep that in mind. Toslink, though? That's fiber optic and thus also galvanically isolated.)
For instance: Apple-produced headphone adapters for iPhones are inexpensive -- like $10 or so. And inside of that diminutive adapter is buried a whole USB DAC, with a headphone amplifier. It's so seamless and low-cost that some folks think I'm crazy when I tell them this, but they measure great and also work great. (They work great as DAC/headphone amps for PCs, too. Android, not so much: It works, but there's a bug [that will probably never be fixed] relating to volume control and low output level.)
Anyway, I identify as an audiophile. I've spent several decades playing with this stuff, sometimes well beyond the level of "serious hobby." I've made some money doing audio stuff. I've also spent some time in the studio, and in front of the stage, making things sound good.
And I'm practical. I promise you that I can wire up a high-end stereo system with metal coathangers that will sound indistinguishable from something connected using only solid silver Kynar-insulated wire that is jacketed in cloth woven by Benedictine monks from the first cutting of wool from a single virgin albino Bolivian alpaca (for "purity") that has been dyed and imbued with post-civet Kopi Luwak (for "balance"), in any correctly-controlled blind A/B/X test.
Trust your senses. And by that, I mean: If it looks like bullshit, and it smells like bullshit, and it tastes like bullshit, then spit it the fuck out. :)
For sorting inexpensive products that actually work from those that have practical issues like hum or noise: That's what Amazon reviews are for.
But there are some very nice things for sale that aren't stupid-expensive boutique items. Schiit, for example, builds their own designs in the US and charges Buick prices for them instead of Bugatti prices -- and their website shows photos of what the devices look like on the inside, too.
...anyway, ground loops are usually real. Professionally, I've encountered them most-often in residential environments when converting a customer's television into any manner of home theater. 100% of the time I've discovered this, it was because some bonehead grounded the cable TV wire or the satellite dish to some ground that was separate and distinct from the home's electrical ground -- which should never, ever happen.
The loop would show up when we introduced the first bit of gear that had a 3-prong plug into their mix of things that previously only had 2-prong plugs. Adding the AV receiver, the subwoofer, or whatever tied the electrical ground to the stupid ground and current would flow between them, producing noise.
(And USB-C is ground-referenced, so keep that in mind. Toslink, though? That's fiber optic and thus also galvanically isolated.)