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M8161
Small Signal Pentode — B7G — Mullard
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Data: High
High quality — base, heater, all universal parameters present, and ≥50% of desirable parameters filled in. Safe to use for design decisions.
↗ Radiomuseum
Known Equivalents & Substitutes
6065
CV4015
Similar Tubes (Not Drop-In Compatible)
EF85
Similar variable-mu RF pentode on B9A base — not pin-compatible
Electrical Specifications
Absolute Maximum
Anode Voltage (max)
Anode Voltage (max, surge)
500
V
Screen Voltage (max)
Screen Voltage (max, surge)
300
V
Anode Dissipation (max)
Anode Dissipation (max)
3
W
Screen Dissipation (max)
Screen Dissipation (max)
0.7
W
Cathode Current (max)
Notes
M8161 is the Mullard special quality designation; 6065 is the RTMA type; CV4015 is the military designation.
Philips interchange confirms: M8161 = CV4015 = 6065.
Amplification factor mu_g2/g1 = 30 (from M8161 datasheet).
Grid 3 cutoff voltage: Vg1 = -7.0 V at Ia = 50 uA.
Group quality level testing includes fatigue tests, shock tests, and stability life tests.
Brans lists many equivalents including W77, VP4A, EF177, UF41.
Pin Layout — B7G
1
2
3
4
5
6
7
1
Control Grid (g1)
2
Cathode (and internal shield)
3
Heater
4
References
https://frank.pocnet.net/sheets/129/m/M8161.pdf
Cathode Current (max)
14
mA
Heater-to-Cathode Voltage (max)
Heater-Cathode Voltage (max)
150
V
Max Grid Resistor
Grid Resistance (max, cathode bias)
0.5
MΩ
Typical Operating
Anode Voltage (typical)
Anode Voltage
200
V
Screen Voltage (typical)
Screen Voltage
200
V
Grid 1 Bias Voltage
Grid Voltage
-2.5
V
Anode Current
Anode Current
8.25
mA
Screen Current
Screen Current
2.1
mA
Anode Resistance
Plate Resistance
900,000
Ω
Transconductance
Transconductance
2.45
mA/V
Capacitances
Grid-to-Plate Capacitance
Grid-to-Plate Capacitance (max)
0.015
pF
other
Grid 1 Cutoff Voltage (100:1 gm reduction)
Grid 1 Cutoff Voltage (100:1 gm reduction)
-27
V
Anode Voltage (max, operating)
Anode Voltage (max, operating)
300
V
Heater
Heater Voltage
Heater Voltage
6.3
V
Heater Current
Heater Current
0.2
A
Heater
5
Anode
6
Suppressor Grid (g3
,
internal shield)
7
Screen Grid (g2)
M8161 — Small Signal Pentode, B7G | Tubeofile | Tubeofile