Hi My Fellow TH'er ILL Digger
First I have not used Grayghost brand headphones so don't know if there is a warranty or not. I suggest that you contact them to see if they will repair or replace them. I know most KOSS headphones have a lifetime warranty. I have several E-9000 Koss Headphones that I have returned to KOSS for repair several times. I just have to pay for the return shipping charges ($8.00). Whites has replaced several of my headphones over the past years and have not required me to pay the return shipping. I have replaced the plug of a few headphones but they usually are not a good as new. As for the tools you will need; I suggest using silver solder, you need a good soldering iron, and electrical tape. Good luck on the repair! ;-)