TID: PX/Win v3.0pr5 PX96-0466M2   
   MSGID: 1:135/392 800fd10b   
   TZUTC: -0500   
   AB>Hi,   
      
   AB>I put a pair of 572B tubes  in my AL-811 amp and they died.   
      
   AB>One went to a plate current of 600 ma and the other 75 ma.   
      
   AB>Anyways, DX engineering tubes are coming.   
      
   AB>I checked all my 572B tubes one at a time and selected the best I could for   
   the   
   AB> amp. The worst case sceneria was 75 ma.   
      
      
   The new tubes were just as crappy. I exchange the amp for a SB-200, did   
   all modes except the start up mod.   
      
   I only use it on SSB and tested it the other day, 500 Watts out. It will   
   do 700 but 500 will or should extend the life of it.   
      
   I did mods of my input caps, that helped on sumo bands   
      
      
   AB>Here goes.   
      
   AB>600 ma   
   AB>150 ma   
   AB>85 ma   
   AB>75 ma.   
      
   AB>Am I going to trash my amp or will the output just drop?   
      
   AB>It's holding at 500 watts right now. For 100 watts in.   
      
   AB>So, should I leave well enough alone or should I only the 2 tubes in there   
   as   
   AB>soon as they arrive?   
      
      
   I have since known that the input caps are vital.   
      
   AB>If one fails short could that take my amp out?   
      
   Still dunno.   
      
   There are resistors below the deck that ten to blow and remove grid   
   current from the tubss.   
      
   There is more but I have to ask a friend who fixes amps, just amps. He   
   is very good at it.   
      
   VY2TM is his call.   
      
   73,   
   Alan   
      
      
   AB>Best 73,   
   AB>Alan   
   AB>VY2XU   
      
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