I just bought a older (?) BJ with a Cannabis Rex in it. I play my 72 Reissue Thinline Tele mostly and some Strats. I try to play the Blues just for fun. The amp seems to be ok and plays well, but it was acting funny, little hiss or crackle so I did the tap on the tubes test. The one all the way on the right (looking in back) glows a lot redder and when tapped on does not sound like the rest. More hollow thud than ring. So I'm gonna replace all tubes. What do you guys suggest?