7R7
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BrandTUNG-SOL
ClassDouble-Diode Pentode
BaseLoctal
Filament6.3V @ 300mA
Construction
Primary TypeDouble-Diode Pentode
EnvelopeGlass
Sections3
Filament / Heater
Heater NotesAC or DC
Absolute Maximum Ratings
Plate Voltage300 V
Plate Dissipation2 W
Grid 2 Voltage100 V
H-C Voltage90 V
Audio Performance
Key Features
- Common cathode
- Low coupling capacitance
- Semi-remote cut-off pentode
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Class A1 Amplifier | 100V | 2100 | 500000 | - | 3.4mA |
| Class A1 Amplifier | 100V | 3000 | 350000 | - | 5.5mA |
| Class A1 Amplifier | 250V | 2200 | 1600000 | - | 3.5mA |
| Class A1 Amplifier | 250V | 3400 | 1000000 | - | 6.2mA |
Application Notes
The 7R7 combines two diodes and one semi-remote cut-off pentode unit with a common cathode. Used as a combined IF amplifier, AVC rectifier, and detector. Pentode unit may also be used in audio amplifier service.
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