Proton, thanks for the useful links and info. One of your links,
http://sound.westhost.com/amp-sound.htm, explains that solid-state amps generally have output impedance below 1 ohm, so the output impedance should not be a worry when evaluating Fiio amps. The low output impedance allows an amp to control resonance more effectively, if I understand your explanation correctly. You also point out that impedance often varies with frequency. However, in the case of the LCD2 rev 2, the graphs at innerfidelity show that the impedance is constant with respect to frequency.
Thanks, jcx, for the useful information. I had not understood dynamic headroom properly. I have read extensively about volume safety levels, but it's nice to see those links again. I have measured decibel levels out of my headphones with an sound pressure meter, as described in this thread.
http://www.head-fi.org/t/148786/measuring-decibels
I browsed through the threads that you linked. Apparently, the basic idea is that on well-mastered music, the instantaneous dynamic peaks can be 20-24 dB louder than the decibel level that shows up on my sound pressure meter on slow mode. When the meter is on fast mode, it still will not be fast enough to pick up the entirety of these peaks, especially since I have to turn a dial to move up to the next 10 dB range on the meter. These peaks are short-lasting enough that my hearing safety can be calculated without taking them into account, but reproducing them accurately will improve the listening experience.
Could you explain the details of how you calculated the power output of the E1 at 60 ohms? I am a professional mathematician, so feel free to get technical. Also, how did you figure out which chip was used and the specs of that chip? I would like to make the same calculations for other portable amplifiers.
I am the kind of person who is considering spending $1000 on a pair of headphones (haven't done it yet), but I'm not the kind of person who particularly enjoys listening to music locked in one place and hooked up to a heavy amp. I find that my enjoyment of listening to music on headphones is a function not only of the sound quality but also of my ability to move around while I listen to the music and by the extent to which I can easily operate the music reproduction system. The more complicated and bulky the amp, software, music player, etc. becomes, the less I can enjoy the music because the more I enter into an analytical mental state rather than an emotional "enjoy the music" mental state. Whereas when I can just pick up my iPod and listen to music quickly and conveniently, I can much more easily enter the mental state that allows me to enjoy music. So to hear that a simple device like the E1 could effectively drive the LCD2 as long as the volume not including peaks is kept under 90 dB is very good news to me. Indeed, for much of my listening, I listen well below 90 dB, say at around 70 dB. Sometimes, I do like to listen loud, even above 90dB, and for that I would need a better amp, depending on the level of the dynamic peaks in my music.
If I understand all this discussion right, though, then even with the most demanding headphones (not including electrostatics), if the volume is kept at very low but audible levels (i.e. 55 dB average, with dynamic peaks maxing at 80 dB), then they can be driven just as well unamped from an iPod output as compared with a $10,000 amplifier. It is only when the volume is turned up that an amplifier provides any benefit. Yet I think many people on this forum would not agree with that claim. Is it safe to say that this is just a matter of psychology?
