I just need something that will allow a 1/4 in from a bass or pre-amp and an input for an MP3 player and run it into headphones. Preferably with an adjustable level for master/mp3/bass. I've seen a few out on the inter-webs but they're almost $200 for a unit that seems rather simple in design/build. The only thing I can think of is maybe a small mixer.. But I'd rather just have a dedicated little box to accomplish what i described.. Ideas?