Ive heard that a tube amp must always be hooked up to a load. My question is when is this essential? I usually fire up my amp in standby, let it heat up, then jam but hook up the speaker before I turn it on. Can the amp be on without the load connected if its in standby? What about if its not in standby but you arent playing yet. Is that ok? I guess the question is at what point will you do damage by not having a load connected. Thanks!