From: jl@glen--canyon.com   
      
   On Sun, 28 Dec 2025 23:53:24 -0500, bitrex  wrote:   
      
   >On 12/28/2025 10:01 PM, john larkin wrote:   
   >> 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   
   >   
   >The 6AC10 is an adorable lil tube, mine's Raytheon-branded but made in   
   >Japan:   
   >   
   >   
   >   
   >I don't really have a use for the "funky regulator" but I like the idea   
   >of using an optocoupler to provide drive for the pass element of a HV   
   >regulator, avoiding high voltage transistors or having to float op amps   
   >and such.   
   >   
   >I have one "tube bin" with some random stuff like the 6AC10 and some 12   
   >volt tubes in it, even a Strobotron...at some point I inherited a couple   
   >packs of 0B2 gas diodes.   
   >   
   >Amazon/eBay sell these little boost modules for tube experimenters with   
   >a HV output and a 6.3 volt output maybe good for an amp or so, they   
   >really hate driving a gas tube directly as a load and the 0B2 flickers   
   >like a neon Christmas candle, some nice noise/chaos on the 'scope too:   
   >   
   >   
      
   I have some Arcturus Blues, some proiximity fuze tubes, an old radar   
   t/r thing (I think), some acorns, a Krytron, a couple of giant   
   transmitting tubes, lots of CRTs, some pretty PMTs.   
      
   Just pretty glass. I don't plan to use any of them.   
      
   https://www.dropbox.com/scl/fo/m2ff4ty142v65omvmqf9k/ADvXu5nmmZ0   
   w2hLulkZYL8?rlkey=z2tncdtgojshzogufp59xgxtw&dl=0   
      
      
   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)