[Knox]

I'm convinced that any headphone or speakers do improve with burn in but it's all subjective and not easily proven

I have just purchased Sennheiser HD25 for use with my computer; I use my Ultrasone HFI-2200 for TV and Hi-Fi

As my computer is a desktop it probably has enough power to drive the phones but the new Senheiser's don't sound as good as the Ultrasone's

I'm currently burning in the Sennheisers and anticipate a noticeable improvement; I'll just leave them playing FM radio overnight for a few nights

If I’m still not happy with the sound from my computer, I may get into aftermarket sound card, DAC and a headphone amplifier

Is it worth it and how to go about it ?
Do I start with upgrading the sound card ?
Then get a headphone amplifier and where does the DAC fit in ?