I don't really have a problem with DACs on PCs, but the amount of noise present on most motherboards is terrible. (I can usually tell when my machine is compiling).

A few years ago I bought some USB DACs and separate headphone amplifiers and it made a world of difference, even to my relatively ancient ears.

At least the iPhone's DACs are absolutely audiophile quality, especially because the idea that "an audiophile quality DAC costs 20x what you see in smartphones" is patently ridiculous. There's no evidence at all that any good as in not flawed DAC will sound the same on nearly any, if not any system.

At the very least, the audio quality degradation of most bluetooth devices has a worse impact than even your average middle tier Android phone's dac.

I'm being completely serious.

Typically a DAC has two components, the digital to analog part and an analog amplifier. So while the D2A won't typically be different, the audio amplification can vastly be different depending upon what you're trying to drive.

Unfortunately you can't remove the audio amplification and replace it with another, unless you're willing to do surgery on your macbook, say.

The best option is to buy a DAC with an amp that drives what you want it to. I have one that drives headphones that works like a charm, and I can hear not just the instruments clearer, but the location of the instruments recorded in stereo space better.

I lucked out when I decided to upgrade my main system to a Ryzen 7. Not really considering audio, I had decided on an Asrock X370 Taichi board mainly because it was known to work with ECC RAM (and it indeed does according to dmesg), and was quite pleasantly surprised when I plugged my headphones into it for a listen. It sounded every bit as good as what I get from a Focusrite Saffire on another system, and even better, the headphone amp has much more power, making it much better for live, uncompressed classical choral recordings than the Focusrite. I can play them at concert volume and not get clipping in the loudest passages. No complaints from me about the DAC or amplifier stage on this motherboard. On the other hand, I haven't tried any recording with it, and for stereo recording my first thought would still be to reach for the Focusrite or my portable recorder and mic preamp, since I'd need 48V phantom power anyway.

That has also been my experience.

I bought an external audio interface to connect a condenser microphone and was shocked at how much better it sounded compared with the audio output at the back of my desktop (Realtek 24 bit...).

I noticed that audio interfaces tend to have a lot of big condensers on the inside. The kind which don't fit in a laptop, and especially in a phone. Now I'm not an electronics expert to comment on this, but I would guess that the big condensers are not in there just for the fun of it. Note that I'm talking about professional audio interfaces (the kind used by music producers, in the $100-$400 range), not audiophile ones (kilo$, buzz words)

The interior of most PCs (and phones) are very noisy from an RF standpoint. I get hiss on my USB headphones (!!!) from just out poorly shielded the case on my computer is.

That said, Apple had traditionally put very well isolated low noise DACs in their products. I'm not sure if that is still the case.

Isn't the story that they don't put any DACs in their products anymore? Or, more accurately, that the DACs have moved to the output devices (headphones, speakers).

Are you 100% sure it's not the USB DAC on your headphones?

If you've inspected it, sure. If not, I would glare at it for a bit.

An audiophile quality DAC costs 20x what you see in smartphones.

You also need an amp for audiophile quality headphones.

Do you know any audiophiles who use phones to listen to music?

I don’t know any audiophiles period. Hence the lack of knowledge on the subject.

I have a couple different sets of speakers and know that my larger ones sound better than the smaller ones (more “tinny” sound), but figured the core difference isn’t the quality of analog output on the source. Rather it’s the larger amplifier and larger size for bass generation.

For Bluetooth the problem is different. While most people will probably not consciously notice the poor audio quality after long hours of listening they will experience fatigue. This is less likely with lossless audio.

I have a 2015 rMBP and its audio sounds as good as through my CEntrance DACport Slim. Maybe my headphones aren't audiophile quality (Grado SR80i, Sony MDR-7506)?

It's possible. I haven't used the CEntrance DACport Slim, but it looks promising. After looking it up I would set the DAC to the high gain setting and drop the volume lower.

And the Grado's look like a good set of headphones.

I would try listening to The King's Singers, which is an A Capella voice group that sings classical music. I can pick out individual voices in space from recordings that were recorded in the late 1980's. A good DAC won't smear them in space, and you can "lock on" to a voice and hear the tonal quality of it individually as if they were standing in front of you.

Please don't be uncivil on HN regardless of how bad someone else's comment was.

It would be a good idea to read https://news.ycombinator.com/newsguidelines.html and make sure you follow them when posting here. Your previous comment broke them as well.