I took a deep look at the Celest CD-2, a $24 dongle DAC/amp that I genuinely think has the best form factor for a smartphone setup—and you cannot convince me otherwise. The whole point here is the T-shaped, single-piece design: no cable, nothing dangling, nothing getting wrapped around in your pocket or bag. You get both 3.5mm and 4.4mm on one tiny body, with a premium-feeling zinc alloy shell that’s beefy and honestly feels way more expensive than it is (though yes, it can stick out like a sore thumb in tight pockets). Sound-wise, the CD-2 is one of the few budget dongles I can confidently call bright and analytical. It prioritizes crispness and clarity over body and “musicality,” so it’s a great match for warmer IEMs or anything that needs a tighter, cleaner low end and more energy up top. The caveat: it can push treble into sibilance on already-bright sets, and there’s an audible noise floor on some sensitive IEMs (not crazy loud, but it’s there if you listen for it). Also, that 4.4mm is not true balanced—same output as 3.5mm—but for $24, having a practical 4.4 option on the go is still a massive win in my book.