If you're looking for better audio at your desk, one of the best things you can do is buy a nice pair of wired headphones and a headphone amp/DAC that can properly drive them. The advantage of wired headphones is they're generally more affordable and more likely to play higher-resolution audio. Good wired headphones really shine when paired with a suitable headphone amp/DAC is going to make them sound their best.
Picking the right pairing of wired headphones and amp/DAC sounds a little daunting, but in reality it isn't all that complicated. The main thing you need to be aware of is the headphone's impedance (measured in ohms), which is the power required to drive them properly, as well as the impedance range of headphone amp/DAC. The good news is that most headphone amp/DACs have a wide range of impedances and, so long as the headphone's impedance falls within that range, the pairing will work great.
Most affordable headphones have a low impedance, meaning they are fairly easy to drive, which is why you can plug them directly into a laptop or computer's headphone jack. However, because the amp/DAC that's built into your laptop or computer isn't great, the audio can sound flat and grainy. If you pair an affordable DAC, like the Schiit Audio Fulla 3 ($99) or the FiiO K5 Pro ($150), even your low impedance headphones are going to sound noticeably better.
If you're thinking about buying wired headphones with a high impedance, they are going to be more difficult to drive and therefore you need to be more diligent in your research before buying a headphone amp/DAC to pair it with. If the amp/DAC isn't powerful enough to drive the headphones,
The Entry-Level Pair
Headphones: Grado SR80e
The Grado SR80e are identical in almost every way to the company's more affordable SR60e headphones; they have the same open-back design and cool industrial flair that make them look like they're straight out of the 1940s. However, Grado upgraded SR80e with improved drivers so they sound a little more detailed, expansive and punchy.
Impedance: 32 ohms
Amp/DAC: Fosi Audio Q4
The Fosi Audio Q4 is one best headphone DAC/amps that you buy for less than $100. It's capable of driving most hi-fi headphones and playing high-resolution audio (up to 24bit/192kHz). It also a bunch of audio control knobs, which few other desktop amps, that allow you to further tweak your how your headphones sound.
Impedance Range: 16 to 200 ohms
The Step-Up Pairing
Headphones: Beyerdynamic DT 990 Pro (250 Ohms)
The Beyerdynamic DT 990 Pro are wired open-back headphones that were originally released about 15 years ago. However, they've become popular again in large parts thanks to gamers (specifically Ninja) who are converting them into high-end gaming headsets (you have to buy a separate boom microphone). They're available in different versions with different — this 250 ohms version being the highest — so make sure you pick the model that your amp can handle.
Impedance: 250 ohms
Amp/DAC: Schiit Audio Hel 2
Schiit Audio makes two different headphones amp/DACs that are designed for gamers. There's the $99 Fulla 3, which is one of our favorite amp/DACs, and there's the Hel 2, which is four times more powerful than the Fulla 3 and adds gain controls. The Hel 2 is the better option for more demanding headphones, like the Beyerdynamic DT 990 Pro.
Impedance Range: 16 to 300 ohms
The Planar Paradise Pairing
Headphones: HiFiMAN Sundara
The HiFiMAN Sundara are planar magnetic open-back headphones that cost less than $500 — which is pretty rare. They sound excellent, specifically their transparency and midrange resolution, and they're extremely comfortable to wear for long periods. Maybe the best part is that they're wonderfully easy to drive. So while you can plug them into your computer and they'll sound good, pairing them with a nice headphone DAC/amp will be a big upgrade.
Impedance: 37 ohms
Amp/DAC: Audioengine D1
The Audioengine D1 is a plug-and-play DAC and headphone amp that was first introduced in 2012, but like many of Audioengine’s products, it’s built to last and still works great. It's more than capable enough to power the HiFiMAN Sundara. Additionally, it has RCA outputs and is capable of powering most bookshelf speakers; in case you want to build your desktop audio system even more in the future.
Impedance Range: 20 to 300 ohms