Originally Posted by Gravit8
You seem a bit self loathing there hahaha... I think were allowed to call it crap xD The guy owns his own blog, he doesn't post sources or any factual data, it's all just biased opinions.
You might call my article crap - I will accept it - but you shouldn´t assume that it´s just biased opinion.
It´s a simple, measurable fact that a high output impedance of any amp will cause a more or less strong frequency deviation on susceptible headphones. Many headphone outputs of stationary amps (and I didn´t mean stationary, dedicated headphone amps) have an output impedance of 120 Ohms or more. The HD-558/598 are very susceptible headphones - as proven by the impedance/frequency relation measured by headroom.com.
Meaning: with some (many?) amps the HD-558/598 will sound way more bassy.
Do you like that deviation? Do you like neutrality more? Those are questions you have to answer yourself. But don´t call my article biased just because you don´t understand the relation of output impedance vs. headphone impedance response.
I assumed knowledge about issues as these to be commonplace; obviously, I was wrong.