I am trying to pick out a pair of headphones under $50, and I think I've narrowed it down to 2, ATH-M30x and Superlux HD 668B. I found a pair of refurbished ATH-M30x's for $47 on Amazon.
I bought a pair of 668Bs a few years ago and I thought it sounded really good, but after about a year of use, the connector between the cord and the headphones wore out. Because of that, I'm reluctant to buy another pair of the 668Bs.
What pair of headphones do you think I should get?
They're completely different cans; opened versus closed. I would probably go with the 668B.
But if you can stretch a wee bit more, I'd recommend the SHP9500. It's built better than the Superlux and sounds great. $55 or so on newegg: https://www.newegg.com/Product/Product.aspx?Item=N82E16826138190
Also, have you tried replacing the connector on your old superlux? Shouldn't be too hard if you have a soldering iron and and a couple minutes.
I have the M30xes and I love them to death, not least of all because I can fold them up to put in my bag. Very portable headphones with excellent sound quality.
I'd like to give the Superlux cans a go. The two sets cater to two different tastes.
I've found that the M30Xes open up a bit once the synthetic leather disintegrates off the pads. They also get considerably more comfortable.