tube amps speaker load

Hi guys! First time posting here, recently picked myself up a Mesa Mpulse 600! Can't wait to play it, only problem is my country (Ireland) is still in lockdown due to the covid pandemic and I have no access to my cabinet. Can I play this head without a cabinet connected to it without causing...

I plan to buy my first tube amp tomorrow (the Blackstar HT1R head). I start with 1 watt! Will use it mostly with my only guitar (I swear I only have one), but will try micing it with my basses anyway... Here is the question: I know that this head needs to see a speaker load (great feature of...