I knew these were used in ICBM's ,I didnt realise they were tested down the barrel of a gun also ,
I think it took some time before semiconductors became as good as tubes in one respect , abillity to withstand radiation , thats why certain branches of military still had tube production into the 80's .
The machines in the clip are amazing ,
You can easily get a hold of premium raytheon submini's for a few dollars a piece , Ive done a couple of nice tube mics with them and I was thinking of trying a HiZ , Di type input stage , possibly encompassed in a barrel jack ,
If these things were designed to survive being blasted from a gun , anything in the sedate suroundings of a recording studio would be a nice easy life .