Thanks! Also got the mugatu shirt :P

When the deal is too good to be true, it probably is. Why would you want to roll the dice with such a bad seller. 

  Yes. I completely understand that. I'm just putting in my experience. 

  I'm using a ferrite bead usb right now, but did not see any difference between one without a ferrite bead. I just happen to have one laying around. 

  No, not that I know of. The in-line mic is usually meant to be use in conjunction with a phone. I haven't seen or read about any DACs that will allow you to use your mic. 

  Money well spent :]

  If you do a quick search in this thread, you will find that there are people that did a comparison of the two. 

Great help... Much appreciated...   Thanks....

  Not a solid comparison. Had the chance to audition a friend's Q701s for a night. I preferred the sound and comfort of the HD600. The Q701 was too analytical for my taste and exploited some of my lower quality tracks. 

  I was once torn also. Still want to own a pair of Grado's though and do plan on investing in a pair down line, just to quench my curiosity.  Was hoping for a 325i or something above that. 

Of course the gain depends on your source also. I find that I need higher gain if I use it with my cellphone, and less if I use it with the Odac. How far into the future will this investment be? :]

  I clipped my O2 myself to 1x/2.5x gain and use 1x gain with my HD600. I am among many that find the O2 sufficient in driving the HD600. Although I do prefer my NFB 12.1 for the HD600 since it adds a little darkness to the sound.      To be honest, that math goes over my head. Been...

  Unfortunately, I do not have any experience with Hifiman products aside from my short lived possession of the HE-300 (sold it). As far as amps go, I only own the O2 and NFB-12.1. Both are efficient to drive HD600 and Denon 2k. Hopefully someone else may point you in the right direction in...

  Well, my stand alone odac also works when I plug in my headphones, but it does not have nearly enough power to actually drive headphones to optimal listening levels. I find that my iems do well with the ODAC alone and adjusting the volume in windows to 100% produces a decent volume. Which amp...

If your amp section is powered off, the amp line out works as a dac only. There should be no quality loss.