From: jl@glen--canyon.com   
      
   On Sun, 28 Dec 2025 14:23:50 -0500, bitrex  wrote:   
      
   >The 6AC10 tube is kind of like 3 12AT7s in the same package, pretty sure   
   >everyone has one of those in their junk box..   
   >   
   >But the transconductance of a triode is wussy, so adding a couple low   
   >voltage transistors makes a better regulator than you could get with   
   >tubes alone. The PSRR is not too shabby for the parts count, better than   
   >you could do with the two other triodes in a traditional diff pair and   
   >then you'd want a current source for the pair and bla bla bla.   
   >   
   >   
   >   
   >You could use an 0B2 for the Zener for that real vintage feel. And if   
   >you stick the optocoupler and transistors underneath the compactron (it   
   >gets toasty) your regulator is now also "thermally compensated"!   
      
   When transistors were just becoming affordable, there was a last-gasp   
   burst of effort to save the tube industry. There were compactrons,   
   nuvistors, cold-cathode tubes, tubes that would run at 12 volt B+.   
      
      
   John Larkin   
   Highland Tech Glen Canyon Design Center   
   Lunatic Fringe Electronics   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)