Voltage - Triode (with diode, heptode or hexode) ·Hexode-Triode
Triode-hexode frequency changer for superheterodyne receivers. The triode supplies the local oscillator while the hexode performs mixing, with heater characteristics tailored to series-heater designs.
The Mullard TH22C is an indirectly heated triode-hexode frequency changer with a common cathode; its supplied sheet refers to TH4A for the non-heater electrical characteristics.
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
2 physical sections, each with unique specifications.
Section 1
No fixed ratings are recorded for this section.
Mullard TH22C oscillator triode, part of a common-cathode triode-hexode frequency changer for series-heater receivers. Heater is 22 V, 0.20 A. Mullard references its TH4A frequency changer for electrical characteristics other than heater ratings; unrelated tubes with similar names must not be used as specification sources.
Section 2
No fixed ratings are recorded for this section.
Mullard TH22C frequency-converter hexode, with common cathode shared by oscillator triode. Nominal heater 22 V / 0.20 A for AC/DC series service. Original manufacturer sheet states TH22C is identical to Mullard TH4A apart from its heater rating, so unverified values from unrelated similarly named tubes are not promoted.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Heater Voltage
22 V
Heater Current
200 mA
Maximum Heater-Cathode Voltage
125 V
Electrical Characteristics Reference
TH4A text
SuppliedSheetStatesIdenticalExceptHeaterRating