Voltage Pentode ·Pentode
High-gain audio pentode with anti-microphonic construction and low-hum heater for microphone and other sensitive preamplifier stages.
The Mullard EF37A is a high-gain AF voltage-amplifying pentode with anti-microphonic construction and low-hum heater.
International Octal
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
1 physical section, each with unique specifications.
Section 1
Published ratings and characteristics promoted from the supplied Brimar source.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Primary application
Audio-frequency voltage amplification
Low-microphony construction
Yes
Low-hum construction
Yes
Data set 02
Published operating points and test conditions from this source.
Heater Voltage
6.3 V
Heater Current
200 mA
Construction
Anti-microphonic
Data set 03
Published operating points and test conditions from this source.
Plate Voltage
250 V
Screen Voltage
100 V
Plate Current
3 mA
Screen Current
0.8 mA
Grid Voltage
-2 V
Transconductance
1800 uS
Plate Resistance
2500000 ohm
Plate-Grid Capacitance Maximum
0.02 pF
Input Capacitance
5.5 pF
Output Capacitance
8.5 pF
Maximum Plate Supply Voltage
550 V
Maximum Plate Voltage
300 V
Maximum Plate Dissipation
1 W
Maximum Screen Voltage
200 V
Maximum Screen Dissipation
0.3 W