b) Taking the exact same signal you're listening to now and passing it through an amplifier can only make it louder, it can't possibly improve it.
:rolleyes:
I know this forum is crazy anti-audiophile, but come on...you can't possibly think that any device capable of generating a 20-20kHz tone is also capable of preserving that tone, without distortion or attenuation when driving any load between 10-1000 ohms, can you?
Assuming current capability isn't the problem; the only difference between a 10 Ohm and a 1000 Ohm load is the voltage needed to power it to the required level. He's not complaining about the volume level so I don't think increasing the voltage will help. Current drive capability? That's what capacitors are for. Almost any old capacitor will do at 20kHz.
Why even bother having an amplifier or a buffer in the first place? Why not just drive the load straight off the DAC?
Because a typical DAC isn't designed to output any possible voltage range, it's assumed you'll connect it to an amplifier. They don't give DACs much current drive ability either, and for the same reason.
His laptop/phone already has an op-amp in it and he says his headphones "sound great" when connected. The problems he has (if any) aren't voltage/current related, they're about noise floor, dynamic range, etc. Getting an external DAC is therefore a good start. OK, it doesn't solve the problem of connecting them to his phone, but it's a start. Probably a much better start than building that amplifier. For $8 I'd get one for the laptop. If the phone suddenly sounds a lot worse than the laptop
then start working on that problem.
PS: If you want a PCM2704 with an amplifier they do those too, eg.:
http://www.ebay.com/itm/121292071586 Yes, I own one. No I can't hear any difference between that and the non-amplified one (not with my headphones anyway, YMMV).
Don't worry, there's a whole subculture dedicated to swapping the capacitors in those boxes if that's your thing (or you can just
pay a couple of bucks extra for ELNA brand capacitors - the audiophile's choice)