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Voltage - Dual Triode (similar) ·Triode-Triode

19J6

Medium-mu twin triode for transformerless television receivers, usable in oscillator, amplifier, and mixer service, including arrangements where one section serves as mixer and the other as oscillator.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 7BJ
Socket code: B7G
Base pins: 7
Nominal heater: 18.9 V / 150 mA

Description

19J6 — Medium-Mu Twin Triode Vacuum Tube

A miniature, common-cathode double triode designed for high-frequency oscillator, amplifier, and mixer applications in television and radio receivers.

Overview

The 19J6 is a miniature medium-mu twin triode vacuum tube featuring a common unipotential cathode shared by both triode sections. Housed in a compact 7-pin glass envelope, the 19J6 is designed for high-frequency applications, including oscillator, mixer, and amplifier service. It is particularly suited for use in "transformerless" television receivers, color television systems, and AC/DC FM and AM receivers. The common-cathode configuration allows the two triode sections to be operated in parallel or in push-pull, enabling versatile circuit designs up to several hundred megacycles.

Construction and Physical Dimensions

The 19J6 is constructed with a miniature glass envelope (T-5 1/2 bulb) and a small-button miniature 7-pin base (7BF or E7-1). The physical dimensions of the tube are:

Maximum overall length: 2-1/8 inches (2.125 in)
Maximum seated height: 1-7/8 inches (1.875 in)
Length from base seat to bulb top (excluding tip): 1-1/2" 3/32"
Maximum diameter: 3/4 inch (0.750 in)

The tube can be mounted and operated in any position. Internally, the two triode sections share a single, common unipotential cathode, which is connected to a single external pin.

Heater and Electrical Ratings

The heater is designed for AC or DC operation with the following nominal ratings:

Heater Voltage: 18.9 V
Heater Current: 0.15 A (150 mA)

Maximum Ratings

The maximum ratings for the 19J6 are established under the Design-Center or RMA Standard M8-210 rating systems. These limits apply to each individual triode section unless otherwise specified:

Parameter	Value
Maximum Plate Voltage	300 V
Maximum Plate Dissipation	1.5 W
Maximum Plate Current	15 mA
Maximum Grid Voltage	-40 V
Maximum Grid Current	8.0 mA
Maximum Grid Circuit Resistance (Self Bias)	0.5 MΩ

The maximum heater-cathode voltage limits vary slightly across different documentation:

Some specifications list a maximum of 90 V (with the heater either negative or positive with respect to the cathode).
Other specifications list a maximum of 100 V (total DC and peak, with the heater either negative or positive with respect to the cathode).

Fixed bias operation is not recommended for the 19J6; self-bias (cathode bias) is the preferred method of operation.

Pin Connections and Basing

The 19J6 uses a 7-pin miniature base (7BF / E7-1). Two different pinout configurations are documented for this basing arrangement:

Standard Configuration

This is the most common pinout configuration for the 7BF base:

Pin 1: Plate (Section 2)
Pin 2: Plate (Section 1)
Pin 3: Heater
Pin 4: Heater
Pin 5: Grid (Section 1)
Pin 6: Grid (Section 2)
Pin 7: Cathode (Common to both sections)

Alternative Configuration

An alternative pinout configuration is also documented:

Pin 1: Plate (Section 2)
Pin 2: Grid (Section 2)
Pin 3: Heater
Pin 4: Heater
Pin 5: Plate (Section 1)
Pin 6: Grid (Section 1)
Pin 7: Cathode (Common to both sections)

Interelectrode Capacitances

The direct interelectrode capacitances of each triode section, measured without an external shield, are approximately:

Grid to Plate: 1.5 pF to 1.6 pF
Grid to Cathode: 2.0 pF to 2.2 pF
Plate to Cathode: 0.4 pF

Typical Operating Conditions and Characteristics

The 19J6 can be operated in several distinct modes, including Class A1 amplification, mixer service, and Class C push-pull oscillation or RF amplification.

Class A1 Amplifier (Each Section)

When operated as a Class A1 amplifier, typical parameters per section are:

Plate Voltage: 100 V
Cathode Bias Resistor: 50 Ω or 150 Ω (These values are specified for both sections operating under the stated conditions)
Plate Current: 8.5 mA
Plate Resistance ( $r_p$ ): 7,100 Ω
Transconductance ( $g_m$ ): 5,300 mhos
Amplification Factor ( $\mu$ ): 38

Mixer Service (Each Section)

In mixer service, the 19J6 can operate under the following typical conditions:

Plate Voltage: 150 V
Cathode Bias Resistor: 810 Ω or 820 Ω (for both units operating)
Oscillator Peak Voltage: 3 V
Plate Current: 4.8 mA
Plate Resistance: 10,000 Ω to 10,200 Ω
Conversion Transconductance: 1,900 mhos
Short-Circuit Input Conductance (at 100 MHz): 96 mhos

Class C Oscillator or RF Amplifier (Push-Pull)

For Class C push-pull operation, typical operating conditions are:

Plate Voltage: 150 V
Grid Voltage: -10 V (obtained via a 625 Ω grid resistor or a 220 Ω cathode resistor)
Plate Current: 30 mA
Grid Current: 16 mA
Driving Power: 0.35 W
Power Output: 3.5 W

Intended Applications and Circuit Configurations

The 19J6 is designed for high-frequency applications up to several hundred megacycles.

Mixer Service: With the grids connected in push-pull and the plates connected in parallel, the tube is highly effective as a mixer at frequencies as high as 600 MHz.
Converter Service: In AC/DC FM and AM receivers, one triode section can be utilized as a mixer while the other section operates as the local oscillator.
Oscillator and RF Amplifier: The tube is suitable as an RF amplifier or oscillator in "transformerless" television and color television receivers. It can be configured to run in parallel or push-pull.

Characteristic Curves and Behavior

The average plate characteristics of the 19J6 show typical triode behavior:

At zero grid bias ( $E_c = 0$ V): Plate current rises steeply, reaching 15 mA at approximately 110 V.
Negative grid bias: As grid bias becomes more negative (down to -18 V or -40 V limit), the curves shift progressively to the right, showing a typical triode knee-less exponential-like onset.
Positive grid bias: Under positive grid bias conditions (up to $E_c = +12$ V or +15 V), the plate current curves show a rapid initial rise at low plate voltages before flattening out. The grid current curves are highest at low plate voltages and decrease as plate voltage increases.

Technical Summary

The 19J6 is a versatile miniature 7-pin medium-mu twin triode featuring a common cathode and an 18.9 V, 150 mA heater. It is optimized for high-frequency applications, including mixer, oscillator, and amplifier service in television and radio receivers. With an amplification factor of 38, transconductance of 5,300 mhos, and plate resistance of 7,100 Ω under typical Class A1 conditions, it provides robust performance in compact, transformerless designs. It can deliver up to 3.5 W of power output in Class C push-pull configuration and operate as a mixer at frequencies up to 600 MHz.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7BJ
Socket code: B7G
Base pins: 7
Nominal heater voltage: 18.9 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7BJ - 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: 7100 Ω
Transconductance: 0.0053 S
Amplification factor: 38
Max plate voltage: 300 V
Max plate dissipation: 1.5 W

Promoted from printed maximum-rating/characteristic columns; additional published values retained in TUBE_SECTION_PARAMETER.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 7100 Ω
Transconductance: 0.0053 S
Amplification factor: 38
Max plate voltage: 300 V
Max plate dissipation: 1.5 W

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

1940 RCA

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

RCA
19
RCA-19J6 is aminiature type of medium—mu twin CLASS A| AMPLIFIER (Cont'd)
Plate Voltage. « « « « » « o = « » o o »
100 V
Plate Voltage. « « « « » « o = « » o o » 100 . . volts
triode unit may be used as amixer, and the other Cathode-Bias Resistor*» .,
50 ohm
triode unit may be used as amixer, and the other Cathode-Bias Resistor*» ., . . . . . . . 50¢ . . ohms
vision receivers of the "transformerless" type. Plate Current. « « « « ¢« « v ¢ « ¢« o » «
8.5 mA
vision receivers of the "transformerless" type. Plate Current. « « « « ¢« « v ¢ « ¢« o » « 8.5 . . ma
voltage (AC OF DC) « « « o « o + « « «
18.9 V
voltage (AC OF DC) « « « o « o + « « « 18.9 . . volts Maximum Ratings, Design-Center Valuest
Current. « o+ o ¢ o s o o s v o s s o«
300 A
Current. « o+ o ¢ o s o o s v o s s o« 0.15 . . ampere PLATE VOLTAGE: « « « « « » 2 « « « « « « 300 max. volts
Direct Interelectrode Capacitances (Each unit approx.)o: PLATE DISSIPATION. + « « o« & & e v » s
1.5 W
Direct Interelectrode Capacitances (Each unit approx.)o: PLATE DISSIPATION. + « « o« & & e v » s 1.5 max. watts
Grid to Plate. « « « « o o s o o s « »
1.5
Grid to Plate. « « « « o o s o o s « » 1.5 .. upt PEAK HEATER-CATHODE VOLTAGE:
8% . . wut respect to cathode:. . . . . 90 max. volts
90 V
8% . . wut respect to cathode:. . . . . 90 max. volts
respect to cathode
90 V
respect to cathode. . . . . 90 max. volts
) Bulb Top (excluding tip)
150 V
) Bulb Top (excluding tip). . . . . 1=-1/2" % 3/32" Plate voltage. « « o« o o ¢ o « o o o & 150 . . volts
Maximum Diameter . . . . « ¢«
810 ohm
Maximum Diameter . . . . « ¢« 4 ¢ . ¢ 4 4 4 s s . . 3/8" Cathode-Bias Resistor»», . . . . . . . 810 . . ohms
BUTD o v v v a h e e e e e e s e e s e e T
3 V
BUTD o v v v a h e e e e e e s e e s e e T-5-1/2 Oscillator Peak Voltage. . « + .+ + . . 3 .. volts
at
96 MHz
at 100 Mc, . . . 96 micromhos
Values are for each unit Plate Current. . ¢« « &« ¢ o o ¢ o « o &
4.8 mA
Values are for each unit Plate Current. . ¢« « &« ¢ o o ¢ o « o & 4.8 ma
PLATE VOLTAGE. . . « « « ¢« ¢ &+ « s « « »
300 V
PLATE VOLTAGE. . . « « « ¢« ¢ &+ « s « « » 300 max. volts o . .
PLATE DISSIPATION. & « o s o o o « o « +
1.5 W
PLATE DISSIPATION. & « o s o o o « o « + 1.5 max. watts With no external shield.
Heater negative with grid circuit should not exceed
0.5
Heater negative with grid circuit should not exceed 0.5 megohm with cathode
¢ ‘;gspecE to cathode
90 V
¢ ‘;gspecE to cathode. . . . . 90 max. volts bias. Operation with fixed bias is not recommended.
Heater pos ré;:e:ttzo cathode
90 V
Heater pos ré;:e:ttzo cathode. . . . . 90 max. volts . gglge is for both units operating at the specified con-
92CM-7061
7061
92CM-7061
92CM-7060
7060
92CM-7060

Characteristic

Plate Resistance . . . « « « « « o o &« o
7200 ohm
Plate Resistance . . . « « « « « o o &« o 7200 . . ohms
oscillator, amplifier, or mixer service in tele— Transconductance . « « » ¢ o o o« o » » &
5300 µS
oscillator, amplifier, or mixer service in tele— Transconductance . « « » ¢ o o o« o » » & 5300 micromhos
BaS€ o+ + o « + o s ¢ o o Small-Button Miniature
10200
BaS€ o+ + o « + o s ¢ o o Small-Button Miniature 7-Pin Plate Resistance . . + » ¢« « o o « o » 10200 . , oOhms
conversion Transconductance. . . .,
1900 µS
conversion Transconductance. . . ., . 1900 micromhos

Data set 02

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

Input capacitance
2 pF
EachSection
Output capacitance
0.4 pF
EachSection
Grid-to-plate capacitance
1.5 pF
EachSection

Other

Plate voltage
100 V
ClassA;EachSection
Cathode resistor
150 Ω
ClassA;EachSection
Plate current
8.5 mA
ClassA;EachSection

Characteristic

Plate resistance
7100 Ω
EachSection
Transconductance
5300 µS
EachSection
Amplification factor
38
EachSection

Data set 03

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate voltage
100 V
ClassA
Plate current
8.5 mA
ClassA

Characteristic

Conversion transconductance
1500 uS
MixerService

Capacitance

Grid to plate
1.5 pF