i've got a max jr (212 nr) and i'm pretty sure i've got a dead preamp tube. no sound coming from the amp, i put new power tubes is, tried diff guitars, and cables too - still nothing. if i'm looking at the back of the combo the preamp tube just to the right of the power tubes isn't lighting up.
two questions - 1. what position is that tube? (v1?,), 2. what do you suggest i put in its place? i pulled the suspect tube and it's a sovtek 12ax7lps. any advice is appreciated!
From what I understand, that tube is your phase inverter, and it's the V3 slot. V1 is the tube on the far right. You can put in any 12AX7 to see if it gets the amp working, but the stock tube supplied by Dr Z is a Groove Tube 12AX7R2, according to their website. Just to confuse the issue, the guys on this board recommended trying a balanced triode 12AX7 for the phase inverter.
I don't know what would cause that to fail. I'm not the right guy to even hazard a guess, but I'm sure someone knowledgeable will come along.
Again, I'm no expert, but a bad rectifier can cause a fuse to blow. You might want to consider picking up an NOS rectifier tube. The old production tubes will hold up considerably longer than a new production tube. I'd suggest contacting Mike at www.kcanostubes.com.