From: pfjw@aol.com   
      
   On Friday, November 13, 2015 at 2:36:18 AM UTC-5, Big Bad Bob wrote:   
      
      
   >    
   > are these tubes mounted vertically or horizontally?  I've seen 5V   
   > rectifiers mounted horizontally before, in an old hifi from the 50's.   
   > That might affect how long the tubes live, depending on whether they're   
   > designed to take it or not.   
   >   
      
   They are mounted conventionally (base-down).    
      
   Quite a bit of eequipment mounts tubes horizontally, a very few upside down.   
   Hickok mounts its tester tubes horizontally - specifically against handbook   
   instructions for the 83 as it happens. Zenith and Motorola have a line of   
   radios with the chassis    
   mounted 'upside down' and Lafayette (amongst a few others) has a line of audio   
   components with the tubes mounted horizontally.   
      
   I keep a big Hickok tester, but I have replaced the rectifiers with SS   
   equivalents to remove the issue. The whole process takes about an hour (and a   
   few bucks for the tube bases, resistors and diodes) most of which is the   
   recalbration process.    
      
   But cutting to the chase - Chinese tubes carry a risk that, as measured   
   against the value of the equipment, seems unreasonable to me. Screening and   
   testing gives only momentary results. The long-term behavior is of much   
   greater interest to me, and    
   observed failure modes if available. As I work mostly in vintage equipment   
   reaching back to the '20s, I have had more than the usual few opportunities to   
   observe failure modes. And those observations have served me well.   
      
   Peter Wieck   
   Melrose Park, PA   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)