First of all, sorry for my poor english. I would like to know the reason why the amps manifacturers build linear amps using three 3cx800a7, 2 3cx1200a7, one 3cx3000a7 and ruskies but no one build a linear amplifire with 2 3cx1500a7 (8877) such as the Alpha sx. What problems they could have ? 73 Paul i8ixo