And this is all the headphone amplifier you need to get the full performance out of the ES50's. Pretty amazing, eh? I was wondering whether this inexpensive headphone amplifier would be able to adequately drive the ES50's because their impedance is only 20 ohms @ 1kHz and the review of the ES50's in the April, 2014 issue of Absolute Sound said you'd need a very sensitive headphone amplifier to avoid hum and noise, but this Musical Fidelity V90-HPA is absolutely dead silent with no signal. So you don't have to shell out for anything fancy to get the max out of the ES50's. You can get the ultimate in listening experience without breaking the bank.

BUT ... the ES50's are custom made for the specific shape of your particular ear canals (which are as unique as finger prints), so you can't demo them to your friends (trying to do it will tear apart their ears!). Also, they're made out of special temperature-sensitive acrylic that will conform so closely to the EXACT shape of your ear canals that after a few minutes they feel as if they're part of your own body and they get MORE comfortable after a few minutes and there is NO pain build-up, as there is with headphones that don't quite fit properly. These were made for listening for hours on end without interruption and with no fatigue, and it's a good thing, too, because you can't put them in and take them out as casually as you put on and take off a pair of headphones. It takes a minute or two to get them in properly AND take them out! With practice, you get better at it, and they'll pop right in, like custom-fitted hearing aids.