Please feel free to redirect me if I'm in anyway hijacking this thread, but while on the topic of DAC's...I have a question. I'm looking at headphone amps vs. DAC's. In regards to HFA's Most seem to contain a DAC. You've got to climb the cost ladder in order to get any kind of digital input option along with the standard analog rca's, where you would even be using the DAC. I realize that many people are using the digital input of their DAC to convert data from PC's and laptops.....but how does one choose? Supposing that you only have budget for one, I think a DAC with a pre-amp function (volume knob) and both analog and multiple format digital inputs would do everything and more that a HFA would do, no? Most of my listening is through my Marantz CD5004 player with Audio-Technica ATH-M50 headphones plugged directly into the 1/4 inch variable outputted jack. Again, wouldn't I be better off sending the digital output from the cd to the DAC, utilizing it's DAC, rather than taking the analog output rca's from the Marantz into the analog input of the DAC? For listening outside of the cans, I have an Adcom GFP 565 feeding signal to 2 GFA 565 monoblocks. Currently I am "between speakers", having sold my Klipsch Chorus's before moving. Is it really a tube advantage to have a DAC with vacuum tubes in it's circuitry? I'm guessing the tubes are in the output stage? Thanks in advance for any advice or enlightenment on this subject which I'm trying to grasp.