Locking RCAs are stuck

Don't know about yours but some are reverse threaded. Try going the opposite direction.

I did:

There once was a couple named Kelly
Who went around belly to belly
Because in their haste
they used library paste
instead of petroleum jelly.

All I can say is be very very careful removing the cables. Don`t want to mess up the rca much less the jack on the equipment. I use Kimber and Cardas cables and I prefer the Cardas because of this very thing thats happened to you. Had the same thing happened to me and I turned the equipment off and let it cool down and got some of those rubber thingies that remove jar lids from the fridge....and that worked but never again will I over tighten those things.

Good luck,

Happy Listening

Wrap a rubber band around both parts and twist them gently with a pliers. And, I think Herman may be correct about the reverse threading.

Apply a hair dryer on medium or low heat to the locked RCAs. This should warm the connectors enough to expand the metal just a bit and allow you to unscrew them.

Your experience is exactly why I dislike locking RCA barrels.