6A8GTX

Ceramic-base pentagrid converter for combined oscillator and mixer service at higher frequencies. GTX construction is specifically intended for high-frequency circuitry, distinguishing it from ordinary 6A8 receiving versions.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: IO
Base pins: 8
Nominal heater: 6.3 V / 300 mA

Description

Ceramic-base pentagrid converter for combined oscillator and mixer service in superheterodyne circuits; GTX construction is intended for high-frequency circuits.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: IO
Base pins: 8
Nominal heater voltage: 6.3 V
Nominal heater current: 300 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

1 physical section, each with unique specifications.

Section 1

Heptode

X-ray radiationInterelectrode capacitances

Max plate voltage: 250 V
Max screen voltage: 100 V
Max cathode current: 14 mA

Hytron 6A8GTX ceramic-base low-loss pentagrid/heptode converter, electrically equivalent in static characteristics to 6A8GT, but optimized for high-frequency operation. Indirect heater 6.3 V 0.3 A. Manufacturer maximum plate voltage 250 V, screen (grids 3 and 5) voltage 100 V, oscillator anode-grid (grid 2) voltage 200 V and total cathode current 14 mA. Grid-2 supply up to 250 V requires a 20 kΩ voltage-dropping resistor above 200 V; supply voltage is not the electrode maximum. Typical at plate 100 V/screen 50 V: plate current 1.2 mA, screen 1.5 mA and CONVERSION conductance 350 µmhos; at plate 250 V/screen 100 V: plate current 3.3 mA, screen 3.2 mA and conversion conductance 500 µmhos. Conversion conductance must not be promoted as intrinsic transconductance. Manufacturer lists interelectrode capacitances (with shield where indicated): grid-4-to-plate approximately 0.20 pF, grid-4-to-grid-2 0.19 pF, grid-4-to-grid-1 0.13 pF, oscillator grid-1-to-grid-2 1.0 pF, RF input 7.5 pF, oscillator output 5.0 pF, mixer output 7.5 pF and oscillator input 6.2 pF. Ceramic base ring/shield contact to ground pin reduces loss; separate physical mixer and oscillator electrode groups do not constitute separate independent tube sections.

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.

No source-specific operating conditions are recorded.