I got a pair of ER-4P. They sound great. I made the adapter using two jacks and two 75 ohm resistors between. I still have no headphone amps, but I can hardly listen any difference with and without the adapter. I'm listening from a portable CD playre (Sony D-E221) and I've to increase the...

I travel by train, 50 min. 2 times a day. Trains are quiet noisy, in particular in the summer with windows open. I listen to different kind of music (classical, jazz, rock) with a portable CD player and, especially for classical or soft music, I can hardly hear the music. I was thinking about...