TUBEOFILE
Search
Compare
FAQ
Tube+
Sign In
Sign In
☰
Loading...
KT30 — Beam Tetrode, B7G | Tubeofile | Tubeofile
← Browse
KT30
Beam Tetrode — B7G — MO Valve Co.
···
+ Compare
⚡ Roll
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
Y13
CV3519
Electrical Specifications
Typical Operating
Anode Voltage (typical)
Anode Voltage (typical)
250
V
Screen Voltage (typical)
Screen Voltage (typical)
250
V
Grid 1 Bias Voltage
Grid 1 Bias Voltage
-12
V
Anode Current
Anode Current
40
mA
Screen Current
Notes
13 V heater at 0.3 A — designed for series-string heater operation in battery receivers.
British 7-pin (M7A) base — an early British base type, not the later B7G miniature.
Very early beam tetrode design from 1934. Found in only 2 radio models at Radiomuseum.
Class A SE at Va=250V, Vg2=250V: Ia=40 mA, Ig2=7 mA, gm=3.9 mA/V, Rk=260 Ω, rl=7500 Ω, Pout=2.7 W.
Pin Layout — B7G
1
2
3
4
5
6
7
1
Anode
2
Screen Grid (g2)
3
Control Grid (g1)
4
References
https://tdsl.duncanamps.com/show.php?des=KT30
https://www.radiomuseum.org/tubes/?tube=KT30
Screen Current
7
mA
Transconductance
Transconductance
3.9
mA/V
Cathode Resistor (self-bias)
Cathode Resistor (self-bias)
260
Ω
Output
Output Power
Output Power
2.7
W
Load Impedance
Optimum Load Impedance
7,500
Ω
Heater
Heater Voltage
Heater Voltage
13
V
Heater Current
Heater Current
0.3
A
Heater
5
Heater
6
Cathode
7
Beam Plates (internally connected to cathode)