YEARS ago - Like mid-70's - I worked on a lot of vacuum tube stuff. We had monster reel-to-reel recorders that used 14" reels of 1" tape. The tape "deck" was a couple of hundred pounds of cast aluminum. The whole thing was 32 inches wide, about that deep and 7 feet tall. 14 channels if I recall correctly and all the amps and power supply were vacuum tube. They were old then, late 50's technology.
The rectifier for the main power supply hung off the back of the cabinet and had four vacuum tube diodes the size of your fist. When one of those tubes let go, it could be spectacular, both visually and audibly. We actually had operators wet themselves when one blew unexpectedly.
One time, it blew a tube violently enough to set the circuit board it was plugged into on fire. Some well-meaning but misguided operator dumped an entire extinguisher of Purple K into the cabinet. Never did get that recorder working again...