I have a MIM Roland Ready Strat that was working flawlessly, until recently. Now, when both TRS and 13 pin cable are plugged in, there is an extreme buzz. Unplugging the TRS removes the buzz. Independently, they both are quiet; together, unusable. Anybody have any ideas on what might be causing this? Thanks!

I am having the same exact problem- when the regular guitar chord is plugged in - even if the selector switch is only on the 13 pin cable- an incredible amount of noise comes out of the speakers that I have the gr-55 runiing into( 13 pin to gr-55) - if I unplug the 1/4" cable all noise goes away- Any one have any ideas ?

Seems this might be likely due to a ground issue.

You mean the ground wire that is routed through the body and connected inside teh back of the guitar near the tremolo? Should the 13 pin and the regular 1/4 each have their own ground? thx