Troublesome about Headamps? The addiction you develop, that is troublesome...
I only have a 4.5V TAH, but I just won't listen to anything without it anymore.
It has a very positive effect on the timing of the music.
I use it with my Etys 4S and iPod on the go, I use it with my Senn HD520II on my home rig, I even use it right now with my iBook and KOSS PortaPro.
I am not so very convinced off the crossfeed though, it works best with the big Sennheiser. With the Etys, the loss of high-end and somewhat inflated bass are just too evident.
Be very sure to consider the 9V TAH as well. I feel the sound to be much improved when I use the 4,5V TAH with a wallwart at IIRC 12V, and I always wonder whether I want some of that extra "punch" on the go, which the 9V should offer.
More trouble:
- you start to stock batterys like corn, wondering whether you prefer "universal" or "Maxi-Tech"... I just thought about an ammunition-belt...
- you start to wonder how so many albums can sell so well being produced that bad.
- you start to notice that your PortaPro has just TOO MUCH BASS! Unbearable!
- being used to Etys, you start to become sociophobic on the rare occasions where you just forgot to charge your iPod and have to listen to what the people on the bus are actually talking about...
- you start an unhealthy diet on coffee and nikotine so you can put aside enough for a better home source, SACD maybe, and then a Cosmic, and then...
Portability:
Well, it's there, you have to turn it on, adjust the volume, and turn it off when you are finished. The TAH is very light and also rather small. I have it in an ugly CaseLogic MD-Case on my belt, along with the iPod. Looks a little dorkish depending on your wardrobe, but nobody laughs at a person with Etys looped over the ears and the black Ray-Bans on