[ARC5] BC453 on 24V

[J Mcvey]

 My bad. the 28D7 is  a dual pentode LOCTAL . The datasheet says that each pentode has a plate dissipation of 3 watts. 400 ma heater!  I didn't think there could be TWO dual pentode types but there is.The R392 uses 26a7 which is dual pentode OCTAL . Plate dissipation on each section is 2W.with 600 ma heater. ( no wonder it gets so hot)
None the less, Both can be replaced with a pair of IRF640's and few resistors. the pair idle around 5ma. 

    On Wednesday, December 11, 2019, 4:19:45 PM EST, CARL HUETHER <k1uhy at comcast.net> wrote:  
 
   Wow, that is the first Ive read about that tube being used.   
   Several years ago I picked up an elevator control module using 3 of them, Sylvania if I remember. One was good for 1W of Class C CW but I never tried to see how much it could be pushed in voltage and power.   
   Carl  
 On December 11, 2019 at 12:46 PM Ian Wilson <ianmwilson73 at gmail.com> wrote: 
 
  Some of those receivers used the 28D7 dual beam power tube. This is quoted  as 175mW audio output in push-pull with 28V supply. That reminds me, I have   some of these "somewhere"...   
   73, ian K3IMW   
   On Tue, Dec 10, 2019 at 4:24 PM Robert Eleazer < releazer at earthlink.net> wrote: 
  
    I used to power up the filaments on my R-11A and reduce the B+ until it quit.  I found I could get down to just a little before I got to 28VDC and still be able to hear a signal.  And with the basic R-11A there was no volume control or gain control.  You just plugged in a headset and listened.       Note that the various BC-1206 receivers all work on 28VDC B+ and filament voltage, as does the R-392, and numerous tube type marker beacon receivers, including the BC-357, BC-1033, and R-666.       WAyne   WB5WSV       ______________________________________________________________ 
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