Ananda is a rather old model and extremely good (in my experience) at handling female vocals, Japanese sweet girl vocals especially. However, it might not be that good for all the rock genres you mentioned.

If all-roundedness is a factor, I would definitely get editions, for it's cheaper and an upgrade to Ananda in my opinion.

I suggest installing an equalizerAPO on your computer and setting the preamp in the equalizer to -10 dbs (depending on how much lower you wish the volume to be) while keeping the computer volume at maximum.

This would help to achieve the more control room you wish to have on JDS amp, while not sacrificing dynamic range.

Simply try to plug the headphone into some other source and plug another headphone to the Fuella and see if which side still got the problem