I've got a couple of pieces of Yamaha gear that haven't been powered up in a while - a CR620 receiver and an M-60 power amp. I powered both up when I first got them but they've been unused for several years. I'm used to working on tube gear and using a variac and/or DBT on startups. I did some searching on the SS forum and here and read some posts that suggest that Yamaha gear, or at least some of it, should not be powered up with variacs or DBTs and that doing so might actually cause damage. So, what about the models listed above? Safe or not?