TUBEOFILE
Search
Compare
FAQ
Tube+
Sign In
Sign In
☰
Loading...
D3a — Small Signal Pentode, Noval | Tubeofile
← Browse
D3a
Small Signal Pentode — Noval
···
+ Compare
Telefunken
↗ r-type.org
↗ TDSL
↗ Radiomuseum
Known Equivalents & Substitutes
7721
CV10804
Electrical Specifications
Section 1 — Pentode
Absolute Maximum
Anode Voltage (max)
Anode Voltage (max)
220
V
Screen Voltage (max)
Screen Voltage (max)
180
V
Anode Dissipation (max)
Anode Dissipation (max)
4.5
W
Screen Dissipation (max)
Screen Dissipation (max)
1.1
W
Cathode Current (max)
Cathode Current (max)
33
mA
Heater-to-Cathode Voltage (max)
Heater-to-Cathode Voltage (max)
120
V
Max Grid Resistor
Max Grid Resistor
0.5
MΩ
Typical Operating
Anode Voltage (typical)
Anode Voltage
190
V
Screen Voltage (typical)
Screen Voltage
160
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-10
V
Anode Current
Anode Current
22
mA
Screen Current
Screen Current
Capacitances
Grid-to-Plate Capacitance
Ca/g1 (Feedback Capacitance)
≤0.035
pF
Grid-to-Cathode Capacitance
Cg1/k (Grid-Cathode Capacitance)
6.8
pF
Anode-to-Cathode Capacitance
Ca/k (Anode-Cathode Capacitance)
<0.050
pF
Input Capacitance
Ce (Input Capacitance)
10
pF
Output Capacitance
Ca (Output Capacitance)
Noise / RF
Equivalent Input Noise Voltage
Noise Figure (100 MHz)
7
µV
other
raeq
raeq
150
Ω
μg2g1
μg2g1
80
—
Section 2 — Triode Strapped
Absolute Maximum
Anode Voltage (max)
Anode Voltage (max)
220
V
Anode Dissipation (max)
Anode Dissipation (max, Pa+Pg2 triode)
4.5
W
Cathode Current (max)
Cathode Current (max)
33
mA
Max Grid Resistor
Max Grid Resistor
0.5
MΩ
Typical Operating
Heater
Heater Voltage
Heater Voltage
6.3
V
Heater Current
Heater Current
0.315
A
Notes
Pin 1 and Pin 3 are both cathode connections (internally connected per datasheet note).
Also manufactured by Siemens, Valvo, and Philips with identical specifications.
Two triode connection methods documented: (a) g2 to anode, g3 to cathode (standard, lower rp); (b) g2 and g3 both to anode (higher Ca/g1 feedback capacitance). Section 2 uses method (a).
If Ck > 10 µF, a bias resistor ≥ 1 kΩ must be provided to protect grid 1 on switching after short interruption in operation.
Vhk_max is asymmetric: 60 V (heater negative of cathode) / 120 V (heater positive of cathode). The 120 V figure is recorded.
Maximum bulb temperature: 190 °C.
Pin Layout — Noval
1
2
3
4
5
6
7
8
9
1
Cathode
2
Control Grid
3
Cathode (connected to pin 1)
References
https://tube-data.com/sheets/128/d/D3a.pdf
6
mA
Anode Resistance
Anode Resistance
120,000
Ω
Transconductance
Transconductance
35
mA/V
Cathode Resistor (self-bias)
Cathode Resistor (self-bias)
400
Ω
2.1
pF
Anode Voltage (typical)
Anode Voltage
160
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-10
V
Anode Current
Anode Current
24
mA
Anode Resistance
Anode Resistance
1,900
Ω
Transconductance
Transconductance
41
mA/V
Amplification Factor (μ)
Amplification Factor (μ)
77
—
Cathode Resistor (self-bias)
Cathode Resistor (self-bias)
470
Ω
other
raeq
raeq
65
Ω
4
Heater
5
Heater
6
Internal Connection
7
Anode
8
Suppressor Grid (shield)
9
Screen Grid