hi Alan, I have recently purchased one of your Firebottle plus phono stages from a fellow WAM member. absolutely loving it so far, great work. this is my first dedicated phono stage and also my first piece of valve equipment I have a few questions.. roughly how often will the valves need replacing and is this an upgrade/improvement opportunity? I did read on a forum that there are other upgrades available..where can I find details if this is the case? thanks in advance .. neil