Data set 01
1958 Mullard Receiving Tubes
Published operating points and test conditions from this source.
SECTION 1
Diode
Application
Application
Signal detection / AVC
SECTION 2
Triode
Application
Application
LF amplification
Voltage - Triode (with diode, heptode or hexode) ·Diode-Diode-Triode
TDD4
Indirectly heated double-diode triode for detector, AVC, and low-frequency amplifier service. Two diodes provide signal and control rectification while the triode supplies the subsequent amplifier stage.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 3
- Base
- -
- Socket code
- B7
- Base pins
- 7
- Nominal heater
- 4 V / 650 mA
Description
Indirectly heated double-diode triode for detector, AVC, and LF amplifier service.
Socket description
Medium 7-contact
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- -
- Socket code
- B7
- Base pins
- 7
- Nominal heater voltage
- 4 V
- Nominal heater current
- 650 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
3 physical sections, each with unique specifications.
Section 1
Diode
X-ray radiationInterelectrode capacitances
- Max cathode current
- 0.8 mA
Mullard TDD4 first physical diode for signal detection/automatic volume control service in an indirectly heated double-diode triode. Shared cathode with second diode and triode, 4 V 0.65 A heater. Maximum diode anode current 0.8 mA and peak inverse anode voltage 200 V; the latter must not be construed as continuous forward anode limit. Both diode systems are represented separately.
Section 2
Triode
X-ray radiationInterelectrode capacitances
- Plate resistance
- 13500 Ω
- Transconductance
- 0.002 S
- Amplification factor
- 27
- Max plate voltage
- 250 V
- Max plate dissipation
- 1.5 W
- Max cathode current
- 10 mA
Mullard TDD4 indirectly heated double-diode triode for detector, AVC and low-frequency amplifier stages. Typical triode operation at anode 250 V, grid -7 V and plate current 4 mA: gm 2.0 mA/V, amplification factor 27, anode resistance 13.5 kΩ. Maximum triode anode voltage 250 V, anode dissipation 1.5 W and cathode current 10 mA. Both diodes and triode share the indirectly heated cathode.
Section 3
Diode
X-ray radiationInterelectrode capacitances
- Max cathode current
- 0.8 mA
Mullard TDD4 second physical diode for detector and AVC rectification service. The two separate diodes and triode share a common indirectly heated cathode. Maximum diode anode current 0.8 mA and peak inverse anode voltage 200 V; do not treat peak inverse voltage as positive continuous anode rating.
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.