From: peterwieck33@gmail.com   
      
   I keep a Dynaco system in my office consisting of a PAS 3x, FM 3 and an ST 35,   
   and includes a Sony 5-disk CD changer. As it happens the 35 is a first-issue   
   device with the US-made output transformers, and multi-voltage power   
   transformer. The system runs    
   for 9 hours per day, 5 days per week, driving an AR Athena speaker system.   
   Until this morning, all tubes in all three Dynaco components were original   
   Dynaco-marked products, being mostly Mullard and Telefunken.    
      
   Well, yesterday, the 35 popped one of the 7247/12DW7 drivers - a fade-to-black   
   in the left channel that followed the driver when I swapped them during the   
   diagnostic process.    
      
   After a bit of research, and after learning that this driver consisted of   
   half-a-12AX and half-a-12AU7, and not having the time to search through my   
   tube stash, where I am sure I have several, I decided to try a pair of   
   clear-top RCA 12AU7s from the    
   couple of sleeves I snagged at Kutztown last Saturday ($4 each, NIB). I was   
   warned from the research that the gain would be lower, but that there were no   
   specific hazards in using this option.    
      
   I dropped them in this morning, they are singing sweetly as I type. And, yes,   
   I need to increase the volume from the preamp some to get the same volume, but   
   not excessively much. From about 9:00 to about 10:15. Still lots to go.    
      
   Note that this is the first failure-in-use of an audio tube I have had in 40   
   years and thousands of hours in the hobby. Failures at turn-on, sure. But not   
   while under use. Interesting!    
      
   Peter Wieck   
   Melrose Park, PA   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)