Well, if you think about it, headphones are, ultimately, just a pair of stereo speakers. I've played my LP through my Vox bass amp. It does sound a touch different than via a guitar amp, but it works. Similarly, I have a Vox 2x12 stereo cab that I keep toying with the idea of trying out with a hifi. It will work. It'll sound different than a hifi speaker set, because it is voice primarily with a guitar's frequencies in mind. Same with headphones. I would expect guitar-specific headphones to be designed to specifically work well for the frequencies a guitar runs at, whereas hifi headphones are designed to cover a wider range of sounds well. TBh, though, I doubt I could tell you which was which in isolation. I'd expect to hear a *difference* against each other, but what sounds *better* will depend on the individual human ear, and the subjective preferences to which it is attached. All done and said, if I was sinking serious money into headphones dedicated to use with a guitar amp, I'd at least look at guitar-specific phones. If I wanted phones I could also use for more general purposes, I'd probably be looking at the hifi stuff. Both will do the job for a guitar amp just fine, they'll jut be voiced slightly differently.