------------ ORIGINAL MESSAGE ------------(may be snipped) On Sun, 8 Apr 2018 10:12:28 -0700, K7RDX wrote: > >Instant on tubes require no such treatment REPLY: There is no such thing as an "instant-on" tube except for some cold-cathode types which have no filament or heater at all. Even a 3-500Z needs a few seconds. 73, Bill W6WRT