to make a long story short, I just picked up a used, but immaculate PHA-1A in the hopes it would drive my Sennheiser 600's I use at work better than my other amp, (Fiio Q1). The Q1 does great with my secondary pair 630VB which is a lower ohm headset, but the 600's @ 300 ohms overwhelms the Q1. Hooked to my PC, (micro USB input), the pha-1a is every thing I hoped for and more. Lotta power for a portable. But, I need help with cabling..... I use a Fiio X-5 player with a 3.5mm line out female jack. Unfortunately the PHA-1A does not have a 3.5mm input. Why? who knows? the amp does have a USB type a input and a micro usb input as well. I tried this piece, usb to stereo 3.5mm female: But the PHA-1A just flashed it's on light, doesn't recognize it. There is little bit of junk available as a micro usb male to 3.55mm stereo male, but NO quality cable that I can find, this is where I need help. Any one have any suggestions?