WL7025

Low-noise, low-hum, low-microphonism high-mu twin triode designed for tape-recorder and high-quality audio preamplifier input stages; electrically similar to the 12AX7 family.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: B9A
Base pins: 9
Nominal heater: 12.6 V / 150 mA

Description

Low-noise, low-hum, low-microphonism twin triode for tape-recorder and high-quality audio preamplifier inputs; electrically similar to 12AX7.

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: 9
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: 6.3 V
Parallel heater current: 300 mA
Series capable: Yes

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: 300 V
Max plate dissipation: 1 W

Westinghouse WL-7025 low-noise, low-hum, low-microphonism audio voltage-amplifier dual triode, electrically similar to 12AX7. First physical triode: rated maximum plate voltage 300 V and dissipation 1 W. At 250 V plate, -2 V grid: gm 1.6 mA/V, amplification factor 100, plate resistance 62.5 kΩ. Series heater 12.6 V 0.15 A or parallel heater 6.3 V 0.30 A. Manufacturer publishes interelectrode capacitances.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 62500 Ω
Transconductance: 0.0016 S
Amplification factor: 100
Max plate voltage: 300 V
Max plate dissipation: 1 W

Westinghouse WL-7025 second physical triode of low-noise audio twin triode for tape-recorder and high-quality preamplifier input service. Maximum plate voltage 300 V, dissipation 1 W. At 250 V plate, -2 V grid: gm 1.6 mA/V, μ 100, plate resistance 62.5 kΩ. Heater allows 12.6 V 0.15 A series connection or 6.3 V 0.30 A parallel connection. Capacitance data provided separately for the physical triodes.

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

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Heater voltage
6.3 V
Rated heater condition
Heater current
300 mA
Rated heater condition

Other

Voltage (cic or dc)
6.3 V
Voltage (cic or dc) .............. 12.6 6.3 Volts Heater-Cathode Voltage:
Current
300 mA
Current ..................... 0 . 15 0.30 Ampere Heater Positive or Negative with respect to
Gridtoplate
4 pF
Gridtoplate ................. I.4 I.4 uuf Grid Voltage:
Bulb
250 V
Bulb........, ............ T-6-1/2 Plate Voltage ................ loo 250 Volts
Base.,,,,,,,, Miniature 9-Pin (JETEC E9-I) Grid Voltage
-2 V
Base.,,,,,,,, Miniature 9-Pin (JETEC E9-I) Grid Voltage ................ -I -2 Volts
Basing
62500 ohm
Basing...... 9A Plate Resistance ............. 80000 62500 Ohms
Mounting Position Any Transconductonce
1600 uS
Mounting Position Any Transconductonce............. 1250 1600 umhos