EL509
EL509 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $28.41 per tube.
The EL509 is a power pentode intended as a TV line deflection amplifier, with an indirectly heated cathode and a top-cap anode connection.
Construction
The tube uses a T12 envelope and a 9C18 (magnoval) base. The heater is designed for parallel supply, requiring 6.3 V at 2 A. Pin assignments are as follows: pin 1 is grid 1, pin 2 is grid 3, pin 3 is grid 2, pins 4 and 5 are the filament connections, pin 6 is grid 2, pin 7 is grid 3, pin 8 is grid 1, and pin 9 is the cathode.
Ratings
The datasheet specifies a maximum anode voltage at zero current of 700 V, a peak anode voltage of 7000 V, and a maximum grid 3 voltage of 1000 V. Maximum anode dissipation is 30 W, and maximum grid 2 dissipation is 7 W. Maximum cathode current is 500 mA, with a peak anode current of 800 mA and a peak grid 2 current of 70 mA. The maximum grid 1 circuit resistance is 400 ohms. In the absolute maximum system, the datasheet allows up to 8 kV and up to 14 W during the cathode heating period.
Operating Conditions
For the stated operating condition, the datasheet gives a grid 2 voltage of 175 V and a grid 2 current of 45 mA. During flyback, the negative grid 1 voltage needed to cut off the tube is 170 V minimum at Va = 7000 V, Vg2 = 175 V, and Zg1 = 1 kohm at line frequency. The pulse duration is limited to 22% of a cycle, with a maximum of 18 microseconds.
Capacitances and Special Notes
Grid 1 to filament capacitance is 200 pF maximum, and grid 1 to anode capacitance is 2.5 pF. Grid 3 may be brought to about +20 V to suppress Barkhausen oscillations and 'snivet' effects.
| Measure | Per tube |
|---|---|
| Median | $28.41 |
| Typical range (25th–75th) | $20.25 – $31.50 |
| Most sales (10th–90th) | $13.00 – $43.75 |
| Extremes incl. outliers | $5.56 – $154.41 |
| Completed sales | 30 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| Svetlana | $30.60 | $29.00 – $32.00 | 12 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $30.25 | 6 |
| used | $20.24 | 10 |
Per-tube prices from completed sales, 2025-12-20 to 2026-09-05. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for EL509, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| Mazda-Belvu | EL509 | PDF (295 KB) |
| JJ | EL509 | PDF (121 KB) |
| Svetlana | EL509 | PDF (58 KB) |
| Philips | EL509 | PDF (17 KB) |
Documents held here and used to write this page.
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