HELP! REALLY STUPID EASY TUBE QUESTION!

Hey guys, i have a randall v2, and my solid state distortion channel suddenly became crappy, the volume fell down and it became really trebley and weird. i was wondering if this could be because of the 12AT7 tube, maybe it failed or something. :?

anyway i was wondering if i could switch the 12AT7 for a tung sol 12AX7 which i put in my tube channel (i have some spare ones. btw those are SOOOOOO GOOD).

thanks ! plz i need an answer quickly

The 12T7 useally effects both channels if its going out.