@fflbrgst so I only have one cable, I'm going to bring it over to a buddies house later next week and try some of his cables.
As far as reversing the cable, I have tried that. I have two bass's with active preamps, only one of them works with the amp. I have a different bass when passive pickups, and that one doesn't work with the amp either.
As far as has it suddenly stopped working, no for the longest time I thought it was on my guitars end as the amp worked with one of me other instruments but never the other. Now after getting several other instruments and it being kinda dicey (all work on my other things, only 2/5 work with my amp) I'm really thinking it's on the amp ens