This topic puzzles me about solid state replacements? Are these tubes unreliable or are they assumed to be hard to get? A fleaPay search revealed many for sale and yes the price varies but one seller has 80 of them all testing as good for $12.99 or best offer each. They also vary in ballon style or shoulder top throughout my search. Who knows I probably even have some in some of my battery radios or hoard. The only solid state conversion I’m pondering is for vibrators but they are hard to find in Saskatchewan and if you find them they are used or NOS mechanical.