ELL80

Twin audio power pentode containing two matched output sections for stereo, two-channel, or push-pull amplifier circuits. It integrates two independent power-output pentodes in one envelope.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: B9A
Base pins: -
Nominal heater: 6.3 V / 550 mA

Description

Twin audio power pentode containing two matched output sections for stereo, two-channel, or push-pull amplifier circuits.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B9A
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 550 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

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 50000 Ω
Transconductance: 0.006 S
Max plate voltage: 300 V
Max screen voltage: 300 V
Max plate dissipation: 12 W
Max screen dissipation: 1.25 W
Max cathode current: 40 mA

Representative section for repeated identical sections.

Section 2

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 50000 Ω
Transconductance: 0.006 S
Max plate voltage: 300 V
Max screen voltage: 300 V
Max plate dissipation: 12 W
Max screen dissipation: 1.25 W
Max cathode current: 40 mA

Second identical physical output-pentode section; added to align physical rows with SectionCount.

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

1959 Telefunken

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

Plate voltage
250 V
EachSection
Screen-grid voltage
250 V
EachSection
Control-grid voltage
-9 V
EachSection
Plate current
24 mA
EachSection
Screen-grid current
4.5 mA
EachSection
Transconductance
6000 uS
EachSection
Plate resistance
50000 Ohm
EachSection

Other

Load resistance
10000 Ohm
ClassA;EachSection
Output power
3 W
ClassA;EachSection
Output power
8.5 W
ClassAB;PushPull;TwoSections
Output power
9.2 W
ClassB;PushPull;TwoSections

Capacitance

Input capacitance
7 pF
EachSection
Output capacitance
4.5 pF
EachSection
Grid-to-plate capacitance maximum
0.2 pF
EachSection