I have a mainline on order. Now I'm saving and waiting for the Senn. HD820's to be released. So I'm looking for a $100.00 or less pair of cans To use while building the mainline. But all the cheap headphones I see are all low impedance. I willing to buy used. But I need a higher impedance for the mainline. I don't want to spend much money because then I have less for the 820's. Thank you all.