Defy 7 re-tube questions

Could any owners of this amp tell me when you have a blowed power tube. Do you need to change also a protective resister like you do on Audio Research power amps or do you just change a fuse. I just want to know if it is easily for yourself to re-tube. Thankyou.
You don't have to replace resisters. You need 4 matched sets of tubes (3 in each set). Bias is set in banks of 3. You need a meter and you have to remove the bottom cover to get to the bias pots. I don't recall the bias level.