Before the 450MKII were purchased I had VTL 300 Deluxe mono blocks. Great amps but tube faults were a major pain. With the 450's tube faults are a breeze. When a tube goes, it's identified by a flashing little green light. The power to the amp is shut, with gloves the tube is replaced, if a fuse went its also replaced. I'm up and running in less the 5 minutes. Auto Biasing between the notes of the music, come on now that's too cool.
