I remembered I had seen these articles from Tonequest on another forum so thought I's post them here. I hope I don't get stern letter from Tonequest. In any event I think they might help answer the question.
First Article
TONEQUEST: We first discovered Bonamassa when he opened for Peter Frampton in Atlanta last year at the Variety
Playhouse. Arriving mid-way though his opening set, Delta Moon guitarist Mark Johnson and I stood transfixed and humbled as Joe tore through a mix of hook-laden rockers and incredibly emotional, bluesy shuffles. We heard shades of Beck at his best and Hendrix, too, while we both surveyed the stage to see what he was using to get that unbelievably clean and saturated tone… It's hard to mistake a couple of Marshall Silver Jubilee heads, even from 50 rows back. As we shot pictures that night for our upcoming Peter Frampton interview, we vowed to track Joe down, which happened in Nashville at Third and Lindsley - a small 'showcase' venue that might seat 100 souls, versus the Variety, which holds 900.
When we arrived in Nashville we were shocked to see that Joe had the identical rig that he had used in Atlanta - a couple of 100W Marshall Silver Jubilees, another 100W reissue Marshall MKII head, and a blackface Fender Showman head with two 4x12 Marshall cabs. Uh, uh… Joe's a blaster, but imagine our surprise when we were able to order a beer without yelling at the dixie chicks slinging the suds while the band played at full tilt. And no, he did not turn down… Joe Bonamassa has indeed invested a big chunk of his relatively short life learning to play the guitar and sing with a passion and fire rarely achieved in a lifetime, yet he has also devoted a great deal of intelligent thought to getting his tone just the way he wants it, every night, regardless of whether he's playing a dump in Columbus, Ohio or an outdoor shed with a capacity of 15,000. Same rig, same mind-altering clean and dirty tone, every night.
Second Article
TONEQUEST: I wonder if you realize just what you've accomplished? The single biggest rub with guitarists seems to remain the entire volume/power, distortion/clean headroom thing. Their big amp is too loud for the venue and they can't get it cooking, their smaller amp doesn't have enough headroom, and the only way they can get both is by using a pedal… But you've cracked the code as far as your shows are concerned, and we've seen you play a corner bar and a big theater with the same rig…
JOE BONAMASSA: It's that baffle, and the baffle is the cheapest part of the whole setup. Even the case that it sits on costs more than the baffle, and it saves me every time. If we're playing the Majestic Theater that holds 2,000 people, it can be even worse than a small club, because those theaters were designed for people to sing and play with no amplification, and the amps really throw in them. When I do a sound check, I will play my guitar from the first couple of rows. If I can sit there and play, have a conversation with myself, and it still feels punchy and warm, we're done. Once the place fills up you won't really hear the stage volume so much. And I will say this about the baffle… a lot of people that use them still have problems. We toured with Indigenous and they had a straight baffle custom built and they were still having problems. With a flat, straight baffle there is still nothing to absorb and deflect the sound - it just goes up and over. The baffle that I use folds up, and I can stagger it so each panel is at right angles to the speakers and it's truly baffling the sound. If I really wanted to get crazy with it I'd get that eggshell foam and put that on the inside of the panels. There are times when I can hear some of the high end coming over the top of the baffle on stage, but knowing how it sounds in front of the stage, I can deal with that. That baffle has just saved me so many times…