I received the Intruder today. I have to admit that using its cousin, the 71b, I was expecting great sound and since the form factor is the same, was curious how the Intruder would stack up with the same size case and now incorporating USB. To start right off, I have never been a big fan of USB listening, but my mind has changed, now. Since this Intruder needs time to burn in, so will my impressions go as the Intruder may or may not change with time. I can say right now with maybe 5 hours of time on the unit that it has tremendous impact, transparency and a subterranean bass. There are a number of phones I need to try out but so far, authority is what first strikes me along with clean insightful impact of musical delivery. Wanting to listen via one of my favorite sources, the iRiver H140, I was a little surprised. Why I wondered, is it not as good as the usb. I am using the line out . . . . oh wait, I am hearing the difference of dacs and while my iRiver is modified with excellent caps, and I enjoy the sound, it can not touch the sound of the dacs inside of the Intruder. A source with USB out or a newer and better dac than the iRiver will serve the Intruder and your listening well. For this I tried the DX100 as a source. Wow, now this is a combination. The amp of the Intruder is truly excellent. The bass delivery of this combo is amazing and awe inspiring. Detail is very evident with the Intruder. It is not etched or just noise but the detail with nuances, which adds to the listening pleasure. You don't feel like you are missing something in the upper frequencies. While the Intruder does not cover up grain or poor treble, it sure doesn't add to any. Very smooth, extended and wonderful in the high range. I love the full bodied midrange that neither jumps forward or is recessed. Listening to the good cuts (there are some too canned sounding) on Dwight Yoakam's, Accoustical recording, the guitar and voice come across so natural and immediate. So far the mids are very neutral but natural. The male and female voice is inviting. When harmonies are done, there is enough separation that you can tell that there are individual voices. That that occupy distinct space. Guitar in the mids is not harsh or warm but clean and melodic, if played that way, as in Hell Freezes Over, "Love will keep us alive" by the Eagles. The bass lines are very to follow in this recording as well, providing a solid foundation. More to follow. I have posted this in the source section as the Intruder to me falls more under the source/amp than purely amp section.