Hello everyone! I am a new member in this forum, thank you for having me and I love what you guys are doing here! I am slowly coming into the audiophile world but by far can't call myself one. My first glimpse into this world was with Sennheiser px-100ii phones(loved them) and after these I got my first Koss PortaPro mic'ed version(I have them for more than a year and use them with an Iphone, Spotify) after reading a lot of reviews here and other sites, I absolutely loved them, they fit my head perfectly and I love the sound, the portabiltiy is also a huge bonus since I don't like the bulky over-ear phones. After reading more and more here I got to know about dac/amps and that they can improve sound quality. Since I use them only outside mostly(cycling alot) and I don't want to void my warranty doing the mods. So I started thinking why not get one for myself, better quality is always better haha, but I have not much knowledge about them and if it would really be an improvement for my Portapros with my budget, which is preferably around 50euro, could go higher maybe if really needed. So my question is: would it be recommended for me to buy a battery powered portable amp with my budget and if yes, what could you guys recommend? I was looking into Fiio products and found that the Fiio A1 is cheap, is it any good? Theres also one used Fiio E10k in my local used product site for 55eur, is buying a used amp advisable? P.S. I have read that people use 75ohm adaptors, would I need one? I have no knowledge about them. Sorry for my bad english and formatting. Any information would be appreciated, thanks.