What are the pros and cons of stiffening the power supply with higher value filter caps. I'm going to replace the filter caps in my Blues Junior and have read that some people are replacing the 47uf cap with a 100uf or attaching another 47uf in parallel as per BillM recommendation. Supposed to make the bass tighter but what does it do to the top end? Is stiffness the opposite of sag, which seems desirable to some. How did Fender arrive at the 47uf value?