Detailed Product Description

The TH 558E is a ceramic-metal tetrode of coaxial structure, employing HypervapotronTM anode cooling, designed for use in AF and RF amplifiers up to 50 MHz. This tube brings high efficiency to medium- and short-wave transmitters. Moreover, the TH 558E s Pyrobloc grids result in highly stable operating characteristics. The anode cooling technique guarantees

Electrical characteristics

Heater supply                                  23 V / 500 A

Amplification factor                          3.7 to 4.9

Transconductance (la = 10/15 A, VG2 = 1000 V)                                         

180 mA / V min.

Mechanical characteristics

Height                                             650 mm

Diameter                                         320 mm

Weight                                            74 kg approx.

Maximum ratings

Anode voltage                                 15 kV

Control-grid voltage                        1 000 V

Screen voltage                                1.25 kV

Peak cathode current                     600 A

Control-grid dissipation                   3 kW

Screen-grid dissipation                    8 kW

Typical operation SW

Output power (from PA)                  550 kW

Anode efficiency at 500 kW             83.5 %

Frequency                                      26 MHz

Heater voltage                                 20.5 V

Anode voltage                                 12.5 kV

Screen-grid dc voltage                    1 100 V

Control-grid dc voltage                    - 500 V