Tube-number record
ECH 21
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ECH 21 is a tube type in the TubeDatabase archive (class: Triode-Heptode). Recorded specifications: brand Philips, construction Multi-section, base Metal/Glass, socket Loctal, maximum plate voltage 250 V, and maximum plate dissipation 2.1 W. The archive does not yet hold a photographed example of this type.
BrandPhilips
ClassTriode-Heptode
BaseLoctal
Filament6.3 V @ 0.33 mA
Construction
Primary TypeMulti-section
EnvelopeGlass
Base MaterialMetal/Glass
Sections2
Filament / Heater
Heater NotesIndirect AC or DC parallel supply
Absolute Maximum Ratings
Plate Voltage250 V
Plate Dissipation2.1 W
Grid 2 Voltage250 V
Audio Performance
Key Features
- Vangrooster (suppressor grid) for low noise
- Variable transconductance (regelbare steilheid)
- High conversion transconductance
- Low frequency drift on shortwave
- Sleutelbuis (Key tube) construction
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Frequency Changer (Mixer) | 250 V | 750 | 1400000 | — | 3 mA |
| Triode Oscillator Section | 100 V | 3200 | — | — | — |
Application Notes
Recommended as a frequency changer/mixer. Heptode section can be used as an IF amplifier and the triode as an AF amplifier. Suitable for phase inversion in push-pull stages.
Datasheets
Datasheet: ECH21.pdf
Download PDFLoading datasheet...
Datasheets courtesy of Frank Philipse via Frank's Electron Tube Data Sheets.
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