I have to be honest, I only ran it one day without the amp. I was coming from a Sennheiser PC350 and I was impressed enough that I converted almost all of my collection to flac files and couldn't be happier. I'm hearing things I haven't before. I must add that I am a 70's, 80's & 90's pop/rock fan. Hope that helps. I've also have the Sennheiser MOMENTUM In-Ear Wireless Black