> Why are you even considering the case of a zero Ohm load with a 16 Ohm source impedance? Modern headphone amps (including really cheap ones) have source imped

> Why are you even considering the case of a zero Ohm load with a 16 Ohm source impedance? Modern headphone amps (including really cheap ones) have source impedances in the range of 1 Ohm or less while headphones can range from 30-ish to 300 or more. Modern tube amps (non hybrid) have significantly higher output impedance because they often have no overall negative feedback and a few special snowflake headphones have impedances as low as 0.1r and 2r. The considerations are definitively relevant for some cases, as well as in general for analysis of the topic.