112RP suddenly sounds muddy

Hi music man fans,
I'm a Dutch owner of a music man 112RP - sixty five. Great amp, but...
Yesterday I was playing with my band with the music man amp. I use a pedalboard in front of it which gets the power from a powerplant (Harley Benton). During a song I suddenly recognized that the sound of the guitar was gone. Apparently I unconsciously pulled out the powercable of the pedalboard with my foot. When I inserted the powercable back into the pedalboard, the amp suddenly sounded much duller and woolly. There is less punch and the treble seems to be gone a bit. The problem isn't in the pedalboard, because when i play directly with my strat through the amp, the problem remains.
What can be the problem? For me it sounds like a rare incident...
Thanks in advance and my apologies for my faulty English proficiency

I will assume that you tried all new cords? That's first. Then guitar. I know you have probably done this but have to be sure. After that, the only thing that comes to mind is that a power surge from plugging the pedal power back in with the amp running may have overextended the speaker voice coil. THIS IS JUST A GUESS. You should try a different speaker BY ITSELF with the amp and see if it changes. Then let us know. Mike.

Thanks for your quick respons. I tried new cords and another guitar allready. It makes no difference. Later today i will put in the original speaker.
I will let you know the outcome.
gr

Today I replaced the Jensen 100W c12K speaker and tested the amp with the original "music man"-speaker (i'm not sure what brand and model it is). Surprisingly the amp sounds bright, clean and punchy again. So the problem was the speaker.
My question to you Mike. How can I prevent that this will happen again? Because it seems like this shouldn't be a problem with a 100W speaker. Should I replace my powerplant of the pedalboard?

By the way: Many thanks!

Maybe not replace it but maybe secure it so the power doesn't come unplugged. Also, speakers, many time, get burned up by having DC on the outputs. You MIGHT want to have the amp tested to see if there is an bunch of DC voltage getting to the speaker. Mike.