I am completely new to the headphone audio world. My experience with speakers is a different story. I have been looking into sets like Sennheiser HD25-1 II for portable use and the HD598 for listening at home. I've also recently considered the AKG Q701. This is besides the point. I am curious as to how the AKG701 is being recommended with the FiiO E10, an amp/DAC that has a 3.5mm output. The HD598 and the Q701 have 1/4" headphone jacks. Is there absolutely no trouble in using an adapter for this scenario? I only recently realized that amplifiers are used on 3.5mm headphones. I figured it was not necessary. Would i see an improvement in the HD25-1 II headphones if i used something like the FiiO E10? Any extra details and explanations beyond what I am asking is completely fine. I love to learn.