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Tube Tinker — Electron Tube Database
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Power - Triode ·Triode

TZ20

Directly heated zero-bias power triode designed primarily for Class B audio service. A pair can provide substantial output without a separate grid-bias supply, making it an efficient audio power device.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
UX4
Base pins
4
Nominal heater
7.5 V / 1.575 A

Description

Zero-bias triode primarily designed for Class B audio operation, providing up to about 80 watts from a pair without a separate grid-bias supply.

Socket description

Medium-shell UX 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
UX4
Base pins
4
Nominal heater voltage
7.5 V
Nominal heater current
1.575 A
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

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Amplification factor
62
Max plate voltage
750 V
Max plate dissipation
20 W

Maximum/characteristic values promoted where clearly published on the source sheet.

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 Taylor Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Grid-plate capacitance

    4.95 pF

    Published general characteristics

  • Grid-filament capacitance

    5.25 pF

    Published general characteristics

  • Plate-filament capacitance

    0.95 pF

    Published general characteristics