Yes I owned one of these years ago and the advice at the time was to not use the standby switch. I, in fact blew two rectifier valves before I discovered this. The amp naturally heats up to operating temeprature if you just turn it on. It takes 15 to 20 seconds or so for the sound to come on. I also remember the amp chewing up a few 12ax7s in the reverb slots. I would recomend buying from a tube seller who has tested their tubes and offer a warrantry on faulty ones like Eurotubes for example. All the preamp slots do call for 12ax7s so go with those.