Voltage - Dual Triode (similar) vacuum tubes

Triode-Triode

Dissimilar dual triode with a high-gain section documented at approximately 55 amplification factor and 6 mA/V transconductance, intended for specialized television-frequency circuitry.

Base

Not recorded

Socket

B9A

Heater

26 V

Sections

2

Triode-Triode

Sylvania 12AD7 low-hum, low-microphonic high-mu dual triode for audio preamplifiers, with two identical 300 V 1 W sections and 12.6 V/6.3 V series-parallel heater.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Medium-mu dual triode for general voltage-amplifier service, offering relatively low plate resistance and useful current capability in a GT-envelope receiving-tube format.

Base

Not recorded

Socket

IO

Heater

12.6 V

Sections

2

Triode-Triode

High-mu dual triode widely specified for RF and AF amplification, oscillators, and frequency-changing circuits, combining substantial transconductance with moderate plate resistance.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Modern 12AT7-family twin triode intended for low-frequency voltage amplification, offering medium-high gain and relatively high transconductance for audio driver and preamplifier applications.

Base

Not recorded

Socket

Not recorded

Heater

6.3 V

Sections

2

Triode-Triode

12AT7-family medium-high-mu twin triode, co-designated 6201, intended for low-frequency voltage amplification and applications requiring the familiar 12AT7 electrical characteristic set.

Base

Not recorded

Socket

Not recorded

Heater

6.3 V

Sections

2

Triode-Triode

Military-specification 12AT7/6201-family twin triode for oscillator, RF, and AF amplifier service, designed for demanding aircraft and missile applications with controlled heater characteristics.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Modern WC/EH 12AT7-family twin triode for low-frequency voltage amplification, retaining medium-high gain and transconductance suited to audio preamplifier and driver circuits.

Base

Not recorded

Socket

Not recorded

Heater

6.3 V

Sections

2

Triode-Triode

Medium-mu twin triode for general amplification, phase inversion, oscillators, and multivibrators, offering relatively low plate resistance and greater current capability than high-mu preamplifier triodes.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Controlled-warm-up medium-mu twin triode documented for AF preamplifier service, combining moderate voltage gain with relatively low plate resistance and useful current-driving capability.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

12AU7-family medium-mu twin triode, co-designated 6189, intended for low-frequency voltage amplification with the characteristic moderate gain and useful current capability of this family.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Military-specification 6189/12AU7-family ruggedized medium-mu twin triode for audio amplification, phase inversion, oscillators, and mixers, combining moderate gain with useful current capability.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Medium-mu twin triode with notably high transconductance and low plate resistance, providing substantially greater current capability than typical small-signal voltage-amplifier dual triodes.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

High-mu twin triode designed for high-gain resistance-coupled AF amplification and phase inversion, also suitable for oscillator service; its amplification factor is approximately 100.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Controlled-warm-up high-mu twin triode for AF preamplifier service, offering approximately 100 amplification factor with manufacturer-specified low equivalent noise and hum voltage.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Modern high-gain 12AX7-family twin triode intended for low-frequency voltage amplification, designed primarily for audio preamplifier stages requiring substantial voltage gain.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

Sovtek 12AX7LP high-mu dual triode with 6.3/12.6 V selectable heater, nominal amplification factor 94 and 330 V maximum plate voltage, designed for linear audio amplification.

Base

9A

Socket

Not recorded

Heater

12.6 V

Sections

2

Triode-Triode

High-mu audio-frequency double triode in MG construction, also designated ECC83MG, providing the classic approximately 100 amplification factor of the 12AX7/ECC83 family.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

Ruggedized high-mu 12AX7-family twin triode for amplifier and oscillator service, designed to withstand shock and vibration while retaining high-gain audio preamplifier characteristics.

Base

NOVAL

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

Modern high-gain 12AX7-family miniature twin triode intended for low-frequency voltage amplification, principally suited to audio preamplifier stages requiring substantial gain.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

Military/premium high-mu twin triode for high-gain voltage amplification, phase inversion, and multivibrator service, with ruggedized construction intended for dependable operation.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Ruggedized high-mu twin triode intended for dependable high-gain voltage-amplifier service, including audio amplification, phase inversion, and related control circuits.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

High-mu ruggedized twin triode for high-gain voltage amplification and phase-inverter service, produced as a high-reliability member of the 12AX7 family.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

Medium-high-mu twin triode designed especially for low-noise voltage amplification, widely suited to low-level audio and other resistance-coupled amplifier stages.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Modern 12AY7-type twin triode intended for low-noise audio voltage amplification, combining moderate gain with useful linearity for preamplifier and driver applications.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

High-mu miniature twin triode for resistance-coupled voltage amplification and phase-inverter service, with two similar triode units and series/parallel heater operation.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

High-mu miniature twin triode for resistance-coupled voltage amplification and phase inversion, an improved 12AZ7-family version intended for general amplifier service.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Indirectly heated triode for general electronic service. Available source material confirms triode construction without establishing a narrower functional application confidently.

Base

Not recorded

Socket

Not recorded

Heater

12.6 V

Sections

2

Triode-Triode

Medium-mu, relatively high-current twin triode designed for voltage-amplifier and driver duties; its robust triode sections also suit television deflection and other demanding signal applications.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Medium-mu twin triode capable of substantially greater current than small-signal high-mu types, used for amplifier, driver, and television deflection service.

Base

9A

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Modern 12BH7A-type medium-mu twin triode intended for low-frequency voltage amplification and driver service, with relatively high current capability and 3.5-watt plate dissipation per section.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

High-mu twin triode designed primarily for voltage-amplifier service, providing two similar high-gain triode sections with series/parallel heater operation.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

High-mu twin triode intended for low-level audio preamplifier service, with operating data for resistance-coupled Class-A amplification and characteristics optimized for small signals.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

High-mu twin triode designed for low-level high-fidelity audio amplification, with manufacturer operating data emphasizing resistance-coupled Class-A service and favorable signal-to-noise performance.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

High-mu twin triode specifically intended as a low-noise resistance-coupled audio voltage amplifier, with operating conditions tailored to low-level signal amplification.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Medium-mu twin triode for general voltage-amplifier, phase-inverter, and driver service, electrically suited to applications requiring moderate gain and useful current capability.

Base

9LP

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Octal high-mu twin triode with a common cathode, intended for resistance-coupled voltage amplification and phase-inverter service in audio and general electronic equipment.

Base

8S

Socket

IO

Heater

12.6 V

Sections

2

Triode-Triode

Octal high-mu twin triode designed for resistance-coupled voltage amplification and phase inversion, providing two similar Class-A triode sections for low-level signal service.

Base

8BD

Socket

IO

Heater

12.6 V

Sections

2

Triode-Triode

Octal medium-mu twin triode for resistance-coupled amplification, phase inversion, and driver applications, offering moderate gain with substantially greater current capability than high-mu voltage-amplifier types.

Base

8BD

Socket

IO

Heater

12.6 V

Sections

2

Triode-Triode

Improved 12SN7-family medium-mu twin triode for voltage amplification, phase inversion, and driver duties, with two similar sections suited to general Class-A service.

Base

8BD

Socket

IO

Heater

12.6 V

Sections

2

Triode-Triode

Premium twin triode derived from the 12SN7 family for applications requiring dependable, stable operation, combining medium gain with useful current capability in two similar sections.

Base

8BD

Socket

IO

Heater

12.6 V

Sections

2

Triode-Triode

Twin triode intended for general voltage-amplifier and related signal applications, using two triode sections in a series-heater form suited to equipment with controlled heater strings.

Base

Not recorded

Socket

B9A

Heater

25 V

Sections

2

Triode-Triode

Twin triode developed for amplifier and signal-processing service in series-heater equipment, providing two triode units within a compact receiving-tube envelope.

Base

Not recorded

Socket

B9A

Heater

6.3 V

Sections

2

Triode-Triode

Twin triode intended for receiving and signal-amplifier applications, with a heater rating suited to series-string operation and two triode sections available for circuit functions.

Base

Not recorded

Socket

B9A

Heater

12.6 V

Sections

2

Triode-Triode

Brimar 13D8 low-mu, balanced dual audio-frequency triode, electrically similar to 12AU7, with 6.3 V parallel or 12.6 V series heater.

Base

B9A

Socket

Not recorded

Heater

6.3 V

Sections

2

Triode-Triode

Brimar 13D9 B9A dual triode with two similar sections, 6.3 V/0.3 A parallel or 12.6 V/0.15 A series heater.

Base

B9A

Socket

Not recorded

Heater

6.3 V

Sections

2

Triode-Triode

RCA 14AF7 medium-mu dual triode with two identical indirectly heated sections, 12.6 V 0.15 A heater, 300 V and 2.5 W maximum ratings per section, 8AC lock-in base.

Base

8AC

Socket

Not recorded

Heater

12.6 V

Sections

2

Triode-Triode

Series-heater counterpart of the 7F7 twin high-mu triode, designed for resistance-coupled voltage amplification and phase-inverter service with two similar amplifier sections.

Base

8AC

Socket

LOCTAL8

Heater

12.6 V

Sections

2