MakeshiftApe
100+ Head-Fier
Nobody can know and understand everything. The fact that you are aware of this and you are willing to listen to those who do understand things is a good thing itself.
Well, amps definitely should not drastically colour the sound! In many (but not in all) cases having enough power is indeed enough.
Distortion happens, when the amp doesn't have enough control over the headphones. The smaller the output impedance of the amp is compared to the headphone impedance, the better control the amp has and the less distortion there is. However, this is not the only factor. Some headphone models "need" more control than others. That's why some headphones work nicely even when the output impedance of the amp is almost as big as the headphone impedance.
62 Ω is minimum at 0 Hz, about 100 Ω is maximum at 20 kHz.
Rout < 100*62*0.06/(100-1.06*62) = 11 Ω.
This means your 16 Ω amp has a bit too large impedance for K702, but the sound may still be good. There shouldn't be issues with distortion. There might be too much treble. Don't worry about it if the sound is great in your opinion. Lower output impedance will change the sound very marginally.
That's good to know. I am partial to maximising every last little thing where possible though - so I'd be happy to purchase an amp that only offered a very marginal improvement to the sound - if that's doable and doesn't set me back more than $100 at the max. Do you think I could get anything in the $50-100 region (or less if that's even possible) that'd be a better fit? And/or have a suggestion on what spec(s) I need to look at? Am I just looking for something with that ~11Ω output impedance you mentioned?