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UL41 — Power Pentode, Rimlock | Tubeofile
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UL41
Power Pentode — Rimlock
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Philips
Data: Medium
Medium quality — at least 60% of universal parameters and pins are present, but some key data is missing. Verify specific values against datasheets before critical use.
↗ TDSL
↗ Radiomuseum
Known Equivalents & Substitutes
CV1977
45A5
N142
Similar Tubes (Not Drop-In Compatible)
EL41
Same pentode structure but 6.3V parallel heater — different heater circuit
UL84
Noval-based successor with improved performance — not pin-compatible
Electrical Specifications
Typical Operating
Anode Voltage (typical)
Anode Voltage (typical)
200
V
Screen Voltage (typical)
Screen Voltage (typical)
200
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-14.2
V
Anode Current
Anode Current
45
mA
Screen Current
Notes
45V/100mA heater for series string operation in AC/DC (transformerless) receivers.
Rimlock B8A base — pins 3 and 4 are internal connections.
Succeeded by UL84 in 1955.
Pin Layout — Rimlock
1
2
3
4
5
6
7
8
1
Anode (Plate)
2
Screen Grid (g2)
3
Internal Connection
4
References
https://frank.pocnet.net/sheets/020/u/UL41.pdf
https://frank.pocnet.net/sheets/030/u/UL41.pdf
Screen Current
8.5
mA
Anode Resistance
Anode Resistance
24,000
Ω
Transconductance
Transconductance
8.2
mA/V
Cathode Resistor (self-bias)
Cathode Resistor (self-bias)
250
Ω
Output
Output Power
Output Power
4.2
W
Load Impedance
Load Impedance
4,300
Ω
Heater
Heater Voltage
Heater Voltage
45
V
Heater Current
Heater Current
0.1
A
Internal Connection
5
Cathode / Suppressor Grid (g3)
6
Control Grid (g1)
7
Heater
8
Heater