AMPEREX TUBE TYPE 12AT7/ECC81

The 12AT7/ECC81[1] is a miniature twin triode designed for use as an
oscillator mixer or amplifier in TV and FM receivers. A center-tapped
heater permits operation of the tube from either a 6.3 volt or a 12.6 
volt heater supply




                               GENERAL CHARACTERISTICS




ELECTRICAL

               Cathode                     Coated, unipotential

                                           Series    Parallel

               Heater Voltage, AC or DC     12.6      6.3 volts
               Heater Current[2]            0.15      0.3 amps

Direct Interelectrode Capacitances    With Shield[3] Without Shield

               Input (each section)          2.3      2.3 uuf
               Output (section 1)           1.15     0.45 uuf
               Output (section 2)           1.45     0.35 uuf
               Grid to Plate (each section)  1.6      1.6 uuf
               Heater to Cathode             2.5      2.5 uuf


MECHANICAL

Maximum Overall Dimensions

               Length                         2 3/16 inches
               Seated Height                  1 15/16 inches
               Diametet                       7/8 inch

              mounting Position             any

              Base                            Small button, 9 pin
                                               RETMA # 9A



[1] The 12AT7~ECC81 is a direct, high-quality replacement for other 
brands of the 12AT7.

[2] When used in equipment which employs series-connected heaters, a
current-limiting device must be inserted to limit the current when 
switching on.

[3] With external shield (RETMA ~315~ connected to cathode of section 
under test.