I previously purchased. An Hp P1 and loved it right out of the box. Great amp/dac. Then I decided what the heck. I needed maybe a backup so purchased the Intruder. After I charged it up, it was a disappointment. I seriously thought of sending it back. I paid all this money for this! Now I'm in my mid 60's and I'm sure my hearing might be going bad but I do know what I like and this amp just didn't cut it. It sounded like it was always screaming at you. But after a few days of use, everything just seemed to settle in, everything is nice and smooth and more than enough power. Great sounding amp.beautifully made. I am only using an iPod classic with these 2 amps, with a set of Grados PS500.