I'm looking to purchase some Ultrasone PROline 650s, but I can't shake off the desire to get the 750s. I found them for $210 and $270 respectively. Any thoughts on which I should buy? Would an iPod be able to sufficiently power either, and can someone explain how that correlates with ohms and impedence? Furthermore, does anyone know how similar the PROline 650s are to the HIF 700s? Thanks a lot!
