Haven't dealt with tubes for a few years but when I did I met Jim McShane. He doesn't take calls nor did Brent Jessee. Both are #1 as far as service. I think the reason Jim doesn't take calls is when I met him we could have talked for hours about tubes and audio. Never dealt with Andy but as you can see he is also highly recommended. Never dealt with Kevin either but Jim said he is a good friend and very knowledgeable.