So I recently saved up enough money for either a schiit magni or a schiit modi, though I’m not sure which to buy first, which would give me the best improvement in audio quality right off the bat? my headphones are relatively easy to drive at 16 ohms (custom one pros). I’ll buy the other in a few months when I’ve saved up enough money for it.
Edit: Or I could just get a schiit fulla (their amp/dac combo).
You need to get a good combo. I am curious do you understand each ones roles...? Read this and then you will understand why I say you need a good combination of them both .. Its worth the money for both....
You should probably get better headphones.. it doesnt sound like any of this will make better headphones.. spend money on better head phones.. you cant make mediocre 16 Ohm headphones better with any amount of dac/amp. To be blunt sorry
Neither will improve audio quality by itself. The DAC can't drive your headphones without an amp, and an amp playing from an amped source will just add to distortion and amplify all that tasty nyoise. You have the get the DAC and amp as a combo for it to do its job. The Magni may also be too much amping for your current headphones, it is known partially for its high gain, but that does not always translate well to easy to drive headphones.
The Fulla is a good choice, though I would research it well. It was known to have major problems when it first came out. There are also other alts like the Geek Out or maybe an O2 + ODAC.
For the record, audio is very subjective, "improvement" means something different to every individual. Be careful when using that word...