I have a question about the AC30 Heritage amp: 1. What does the bass shift do? Does it have to match the brillance number on the switch? Do I need to turn the amp of if I'm switching this? 2. Do I need to turn the amp off if switching the EF86 switch from pentode to triode? Does the EF86 switch have to match the mode the amp is running in? Ie if tha amp is in Pentode mode, does the EF8 switch have to be in pentode & vice versa? Thanks! Just got this amp and it sounds great!