Iconic 3-500z/g Tube, Plate Dissipation, Prices of New Amplifiers, Instead Consider a Used Drake L4b

The 3-500z and 3-500zg are iconic tubes. So what does plate dissipation mean? Also, consider the 572b and 811a tubes. New amps are very expensive and there are not many in stock the retailers Consider a used amp like the Drake L4B. Jim W6LG your YouTube Elmer does some quick math to explain some important things to remember