TUBE 5-125B / 4E27A

GENERAL DESCRIPTION


photo 5-125B The 5-125B / 4E27A is a power pentode intended for use as a modulator, oscillator or amplifier. The driving-power requirement is very low, and neutralization problems are simplified or eliminated entirely. The tube has a maximum plate-dissipation rating of 125 watts and a maximum plate voltage rating of 4000 volts at frequencies up to 75 Mc. Cooling is by convection and radiation. Type 5-125B / 4E27A unilaterally replaces type 4E27

The 5-125B / 4E27A in class-C r-f service will deliver up to 375 watts plate power output with less than 2 watts driving power. It will deliver up to 75 watts of carrier for suppressor modulation.

Two 5-125B / 4E27A's will deliver up to 300 watts maximum-signal plate power output in class AB1 modulator service, 400 watts in class AB2 with less than 1 watt driving power.		 picture 5-125B


TECHNICAL SPECIFICATIONS
ELECTRICAL
Filament, Thoriated Tungsten:
 Voltage
 Current
5.0 ac or dc volts
7.5 amp
Transductance (Approx.)
For plate volts = 2500, grid-No.3 volts = 0,
grid-No.2 volts = 500, and plate ma. = 50

2150 μmhos
Mu Factor, Grid No.2 to Grid No.1 5
Direct Interelectrode Capacitances:
 Grid No.1 to plate
 Input
 Output
0.08 μμf
10.5 μμf
4.7 μμf
MECHANICAL
Mounting Position Vertical, base down or up
Maximum Overall Length 5-9/16"
Seated Length 5-3/8" ± 1/4"
Maximum Diameter 2-3/4"
Weight 6 ounces
Base Ventilated Medium-Metal-Shell Giant 7-Pin
Seal Temperature (Plate and stem) 225 max. °C
Bulb Temperature (At hottest point) 250 max. °C
Specifications may change without notice

THIS TUBE IS USED IN THE FOLLOWING SHORTWAVE BROADCAST TRANSMITTERS
Manufacturer Transmitter specifications Power in kW
RCA BHF-50A 50
BHF-50B 50


THIS TUBE IS AVAILABLE FROM
Manufacturer Rebuilder Distributor
Penta Laboratories



PRICE LEVEL (US$)
1 2 3 4 5 6
0 - 10 10 - 100 100 - 1000 1000 - 10,000 10,000 - 50,000 50,000 - 100,000