Voltage Pentode ·Pentode
High-transconductance long-life pentode designed for wide-band amplification, explicitly co-designated with type 7721.
The Telefunken D3A is a high-transconductance long-life pentode for wide-band amplification, with the sheet explicitly pairing D3A and 7721.
Small-button Noval 9-contact
General specifications
Properties common to every published source and operating point.
Electrical assignments shared by every tube using this base designation.
| Terminal | Section | Connection | Evidence |
|---|---|---|---|
| PIN1Base Pin | — | K — Cathode Original chart label: K; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN2Base Pin | — | G1 — Control Grid Original chart label: G1; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN3Base Pin | — | K — Cathode Original chart label: K; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN4Base Pin | — | H — Heater Original chart label: H; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN5Base Pin | — | H — Heater Original chart label: H; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN6Base Pin | — | IC Original chart label: IC; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN7Base Pin | — | P — Plate (Anode) Original chart label: P; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN8Base Pin | — | G3 — Suppressor GridGroup 9EQ8 Original chart label: G3; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN8Base Pin | — | IS — Internal ScreenGroup 9EQ8 Original chart label: IS; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
| PIN9Base Pin | — | G2 — Screen Grid Original chart label: G2; manufacturer verification pending | Unverified EIA Base Connections, printed page 132, 9EQ |
1 physical section, each with unique specifications.
Section 1
Wideband pentode values; peak plate/screen ratings retained as parameters.
Source-dependent data
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 01
Published operating points and test conditions from this source.
Plate Supply Voltage
190 V
Screen Supply Voltage
160 V
Plate Current
24 mA
Transconductance
35000 uS
Plate Resistance
120000 ohm
Guaranteed Life
10000 h
Average of 100 tubes
Noise Figure
7 dB
100MHz
Approximate Gain-Bandwidth Figure
230 MHz
Data set 02
Published operating points and test conditions from this source.
Input capacitance
10 pF
Output capacitance
2 pF
Grid-to-plate capacitance
0.035 pF
Peak plate voltage
400 V
IntermittentOperation
Peak screen-grid voltage
400 V
IntermittentOperation
Plate supply voltage
190 V
ClassA
Screen-grid supply voltage
160 V
ClassA
Plate current
22 mA
Screen-grid current
6 mA
Equivalent noise resistance
50 Ohm
Data set 03
Published operating points and test conditions from this source.
Typical Plate Voltage
190 V
PentodeConnection
Typical Screen Voltage
160 V
PentodeConnection
Typical Plate Current
22 mA
PentodeConnection
Typical Screen Current
6 mA
PentodeConnection
Data set 04
Published operating points and test conditions from this source.
Input capacitance
10 pF
Output capacitance
2 pF
Grid-to-plate capacitance
0.035 pF
Peak plate voltage
400 V
IntermittentOperation
Peak screen-grid voltage
400 V
IntermittentOperation
Plate supply voltage
190 V
ClassA
Screen-grid supply voltage
160 V
ClassA
Transconductance minimum
30000 uS
Transconductance maximum
40000 uS
Plate current
22 mA
Screen-grid current
6 mA
Transconductance
35000 uS
Plate resistance
0.12 MOhm
Equivalent noise resistance
150 Ohm
Data set 05
Published operating points and test conditions from this source.
Heater voltage
6.3 V
Nominal
Heater current
315 mA
Nominal
Life test
10000 hours
Published datasheet value
Heater current I
315 mA
Published datasheet value
Anode current I,
22 mA
Published datasheet value
Mutual conductance S
35 mA/V
Published datasheet value
Heater voltage Vi
6.3 v
Published datasheet value
Heater current I¢
315 mA
Published datasheet value
Anode supply voltage Vba
190 v
Published datasheet value
Grid No
2 s
Published datasheet value
Grid No
3 v
Published datasheet value
Grid No.l supply voltage +Vbgl
10 A
Published datasheet value
Anode current I
22 mA
Published datasheet value
Grid No
2 mA
Published datasheet value
Mutual conductance S
35 mA/V
Published datasheet value
Negative grid current —Igl max
0.3 ma
Published datasheet value
Frequency =
100 MHz
Published datasheet value
Frequency =
100 MHz
Published datasheet value
Frequency =
100 MHz
Published datasheet value
As triode (grid No
2 a
Published datasheet value
Anode supply voltage Vba
160 A
Published datasheet value
Grid No
3 v
Published datasheet value
Grid No.l supply voltage +Vbgl
10 v
Published datasheet value
Anode current Iy
24 mA
Published datasheet value
Mutual conductance S
41 mA/V
Published datasheet value
anode and other electrodes Ring min
500 MΩ
Published datasheet value
Voltage between electrodes =
300 V
Published datasheet value
grid No
1 a
Published datasheet value
Voltage between electrodes =
50 V
Published datasheet value
cathode, heater and screen Cgl/gZgSkfs
10 pF
Published datasheet value