Help My cables are too tight

I have the TMC cables and you do need to unscrew the locking covers partway to slide them over the female RCA plugs. They should have no problem unless your plugs are recessed (the locking covers are fat and will not always fit in the wholes aroung recessed plugs. TMC has a FAQ page on their website with some installation tips.

I almost had the same experience with my Harmonic Technology Pro Silway IIs. Luckily for me when I first got the cables the twist locks were on loose, so it was obvious that they were made for tightening after plugging them in.

I tried an MIT digital cable one time, which had locking rca plugs. Even backed off all the way, I hardly could get it on and off. Aside from not liking how it sounded, I was worried I was going to damage my equipment!