i wasn't sure where to put this.....

I have a Mesa Boogie Maverick 2x12 amp. I went turn it on a week ago, and the clean channel is really low in volume. I turned up the volume, master volume, etc. and the signal was barely coming through....i turned on the distorted channel and it was normal (very loud)...i thought it was the tubes so i put all new ones in but it didn't fix the problem. Any ideas? Any help would be of help.

Many thanks.
Sonny