The 6C33C-B is a power triode designed for use as a series 
  voltage regulator. The 6C33C-B has very high perveance and 
  very high transconductance. It has high current capabilities, 
  making it suitable for Output Transformerless audio power 
  amplifiers.

                                  General Data

                               Heater Characteristics

     Heater voltage....................6.3 or 12.6 ac or dc 
     Heater current....................6.4 or  3.3 amps 

                         Direct Interelectrode Capacitances 

     Input...................................30.0 pf
     Output..................................10.5 pf
     Transfer................................31.0 pf 

                                 Mechanical Data

     Mounting position.......................Vertical 
     Overall length..........................5.25" (max) 
     Seated height...........................4.75" (max) 
     Diameter................................2.5" (avg) 
     Base....................................Septar 

                                 Pin Arrangment



                             Pin 1...Heater 
                             Pin 2...Heater 
                             Pin 3...Cathode 
                             Pin 4...Anode  (thick)
                             Pin 5...Grid 1 
                             Pin 6...Heater 
                             Pin 7...Heater 

                              Absolute Maximum Ratings 
                      (according to manufacturer datasheet)

     Anode voltage...........................600 V (if tube isn't heated)
                                             400 V (if Pa < 30 Watts)
                                             250 V (if Pa > 30 Watts)    
     Anode dissipation.......................60 watts 
     Cathode current.........................630 milliamps 
     Heater to cathode.......................+-300 volts 
     Maximum grid 1 resistance...............200,000 ohms 


  Typical Characteristics for using in voltage series regulators



     Anode voltage...........................120
     Cathode resistor........................35 ohms 
     Anode current...........................550 milliamps 
     Transconductance(Gm)....................40000 micromhos 
     Anode resistance........................65-80 ohms