No, it's the guitar. I can tell by nuances in the guitar's sound that couldn't really be diddled with by twisting knobs. It's amazing how good some really old, beat-up guiars can sound.

Besides, Willie's has an extra sound hole. . . .

Although I, personally, am not that enthralled with its sound. It tends to sound a bit harsh, especially when he lays into to it hard with the pick.

Don Firth