its time for new tubes in my 5150 and i have never done this before so i dont know much about it. do i need to bias the head or can i just put the tubes in and be on my way? on the eurotubes site it says the tube kit is "plug and play" so i assume this means i do not need to bias. also it says to put a speific tube in "v1" what position is v1? the head is an older model with eddies signature on the back and it just says "EVH" in bold black letters on the front. thanks!