From: pfjw@aol.com   
      
   On Tuesday, July 25, 2017 at 3:55:33 AM UTC-4, Big Bad Bob wrote:   
      
   > I expect a simple series resistor does the trick, but an actual tube's   
   > behavior might be nonlinear...   
      
   Yes. The 5AR4/GZ34 and related clones are a (relatively) slow-onset rectifier   
   that (theoretically) allows the output tubes to get hot before seeing B+.   
   This, thereby, reduces the strain on the filter caps.   
      
   The Weber "copper top" et.al. solid-state replacements are not quite as slow,   
   but neither are they as expensive as a decent 5AR4, and also should last   
   longer.   
      
   Peter Wieck   
   Melrose Park, PA   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)