ampage
tube data
ampage
tube data

7581A
BEAM POWER TUBE
PinElement
1none
2Heater (Filament)
3Plate (Anode)
4Screen Grid
5Control Grid
6none
7Heater (Filament)
8Cathode
Used in the output stage of audio amplifying
equipment, especially units designed to have
ample reserve of power-delivering ability.
These tubes provide high power output,
sensitivity, and high efficiency. Power output at
all levels has low third- and higher-order
harmonics. Tubes require octal socket and
may be mounted in any position. It is especially
important that these tubes, like other
power-handling tubes, be adequately
ventilated. For typical operation as push-pull
class A1, class AB1, and class AB2 amplifier,
refer to type 6L6GC .



Heater Voltage (AC/DC) 6.3volts
Heater Current0.9ampere
Heater Warm-up Time (Average)11seconds


Peak Heater-Cathode Voltage
Heater negative with respect to cathode200 maxvolts
Heater positive with respect to cathode200 max


Direct Interelectrode Capacitance (Approx.)
Grid No.1 to Plate0.6pf
Grid No.1 to Cathode, Heater, Grid No.2, and Grid No.310
Plate to Cathode, Heater, Grid Ho.2, and Grid No.36.5

CLASS A1 AMPLIFIER


Maximum Ratings (Design Center Values)
Plate Voltage500volts
Grid-No.2 (Screen-Grid) Voltage450
Plate Dissipation35watts
Grid-No.2 Input5


Typical Operation
Plate Voltage70250volts
Grid-No.2 Voltage300250
Grid-No.1 (Control-Grid) Voltage0-14
Plate Resistance (Approx.) - 22500ohms
Transconductance - 6000umhos
Plate Current21072ma
Grid-No.2 Current255

CLASS A1 AMPLIFIER - Triode Connection
(Grid No. 2 connected to plate)


Maximum Ratings (Design Center Values)
Plate Voltage450volts
Plate Dissipation35watts


Typical Operation
Plate Voltage250volts
Grid-No.1 (Control-Grid) Voltage-20
Peak AF Grid-No.1 Voltage20
Zero-Signal Plate Current40ma
Maximum-Signal Plate Current44
Plate Resistance (Approx.)1700ohms
Amplification Factor8
Transconductance4700umhos
Load Resistance5000ohms
Total Harmonic Distortion6%
Maximum-Signal Power Output1.4watts

Maximum Circuit Values
Grid No. 1 Circuit Resistance
For fixed-bias operation0.1megohm
For cathode-bias operation0.5