[musikevan]

For those who own the best high-impedance phones such as hd600, dt880, etc, if you upgraded, did you switch to low impedance? Amplification would be easier and cheaper, don't know if I should take this route.

 

[cmlf]

Actually not.. it is very difficult to find a good low-impedance amp with low price. Based on my knowledge, those high quality amp with the ability to handle low-impedance headphone always cost more than 2000 thousand dollars (such as p1u, hp4) 
 
Don't believe that those low-impedance headphone can sound provide a good sound without a good amp (although some yes, like edx,but they are rare) so change to a low-impedance headphone will not lower you budget on amp.
 
So before upgrade the headphone, many people will try to upgrade the amp first, then choose another better high impedance headphone as follow. 

 

[castleofargh]

it's simply not something that can be dumbed down to impedance and sound quality, or impedance and hard to drive. you can actually get 300ohm headphones that are easier to drive than some ortho stuff at less than 100ohm but very low sensitivity.
as for money, there are cheap yet rather powerful amps. unless you're looking for portable headphones to use even with a cellphone, I'm not sure going low impedance is a way to save money. I'm not sure there is any relation between price and headphone impedance or the amp to drive it.