20EZ7

High-mu twin triode intended for high-gain, low-level audio preamplifier service, with two similar sections having an amplification factor near 100 and low operating current.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: B12C
Base pins: -
Nominal heater: 20 V / 100 mA

Description

High-mu twin triode for high-gain low-level audio preamplifier service.

Socket description

Duodecar 12-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B12C
Base pins: -
Nominal heater voltage: 20 V
Nominal heater current: 100 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 62500 Ω
Transconductance: 0.0016 S
Amplification factor: 100
Max plate voltage: 330 V
Max plate dissipation: 1.2 W
Max cathode current: 10 mA

Representative row for two identical high-mu triode sections.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 62500 Ω
Transconductance: 0.0016 S
Amplification factor: 100
Max plate voltage: 330 V
Max plate dissipation: 1.2 W
Max cathode current: 10 mA

Second physical triode section; electrically identical twin section.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater voltage
20 V
Heater current
100 mA
Plate voltage
100 V
ClassA;EachSection
Grid voltage
-1 V
ClassA;EachSection
Plate current
0.5 mA
ClassA;EachSection
Plate voltage
250 V
ClassA;EachSection
Grid voltage
-2 V
ClassA;EachSection
Plate current
1.2 mA
ClassA;EachSection
Maximum plate voltage
330 V
EachSection
Maximum negative grid-bias magnitude
55 V
EachSection
Plate dissipation
1.2 W
EachSection
Peak heater-cathode voltage heater negative
200 V
Peak heater-cathode voltage heater positive
200 V

Characteristic

Amplification factor
100
EachSection
Plate resistance
80000 ohm
EachSection
Transconductance
1250 uS
EachSection
Plate resistance
62500 ohm
EachSection
Transconductance
1600 uS
EachSection

Capacitance

Grid-to-plate capacitance
1.5 pF
EachSection
Grid-to-cathode/heater capacitance
1.6 pF
EachSection