Tube-number record
UFM11
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BrandTelefunken
ClassVariable-mu AF Pentode with Tuning Indicator
BaseSide-contact (P-base)
Filament15 V @ 100 mA
Construction
Primary TypePentode
EnvelopeGlass
SectionsSingle
Filament / Heater
Heater NotesSerial heating
Absolute Maximum Ratings
Plate Voltage300 V
Plate Dissipation0.4 W
Grid 2 Voltage300 V
Grid 1 Voltage-1.3 V
Cathode Current4 mA
H-C Voltage50 V
Audio Performance
Typical THD1.1%
Key Features
- Variable-mu Pentode
- Magic eye tuning indicator
- AF amplifier
- Steel series
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Ub = 200V, initial | 69 V | 173.3 | 600000 | 104 | 0.77 mA |
| Ub = 200V, regulated | 125 V | 4.3 | 3000000 | 13 | 0.44 mA |
| Ub = 100V, initial | 40 V | 192.5 | 400000 | 77 | 0.35 mA |
| Ub = 100V, regulated | 64 V | 3.3 | 3000000 | 10 | 0.21 mA |
Application Notes
The UFM11 is a combined AF amplifier pentode and magic eye tuning indicator designed for AC/DC receivers. In typical operation, the grid voltage is adjusted to provide both signal amplification and visual tuning indication.
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