7722
7722 is also designated E280F. Completed sales put the typical price at $221.72 per tube.
The 7722 is a special-quality pentode in a miniature envelope with a 9-pin base, designed for use as a wideband amplifier.
Construction
The 7722 has a coated unipotential cathode, a T-6 1/2 bulb, and a 9-pin miniature button base. Its maximum overall height is 2.43 inches, maximum seated height is 2.15 inches, maximum height from base to shoulder is 1.88 inches, and maximum diameter is 0.875 inches. The tube can be operated in any mounting position.
Ratings
The heater is rated at 6.3 volts and draws 320 mA. Maximum peak heater-cathode voltage is 60 volts with the heater negative to the cathode and 120 volts with the heater positive to the cathode. Maximum anode voltage is 400 volts (v_a_o) and 220 volts (v_a), with a maximum anode dissipation of 4 W. Maximum grid No. 2 voltage is 400 volts (v_g2_o) and 180 volts (v_g2), with a maximum grid No. 2 dissipation of 1.1 W. Maximum cathode current is 30 mA. Maximum grid No. 1 current is 5 mA; maximum negative grid No. 1 voltage is 50 V and maximum positive grid No. 1 voltage is 2 V. Maximum grid No. 1 resistance is 0.5 MΩ. Maximum bulb temperature is 180 °C.
Characteristics
Capacitances are 9.3 μμf input, 2.1 μμf output, and 0.035 μμf grid No. 1 to plate. Under nominal operating conditions—anode supply voltage of 190 V, grid No. 2 supply voltage of 160 V, grid No. 3 at 0 V, grid No. 1 supply voltage of +8 V, and a cathode resistor of 370 Ω—the anode current is 20 mA, grid No. 2 current is 6 mA, mutual conductance is 26 mA/V, internal resistance is 100 kΩ, and amplification factor is 60. Maximum negative grid current is 0.3 μΑ, and maximum equivalent noise resistance is 220 Ω.
When connected as a triode, with grid No. 2 connected to the anode and grid No. 3 connected to the cathode, and with an anode supply voltage of 160 V, grid No. 1 supply voltage of +8 V, and a cathode resistor of 400 Ω, the anode current is 24 mA, mutual conductance is 33 mA/V, internal resistance is 1.8 kΩ, and amplification factor is 60.
Base Connections
Pin 1 is the cathode, pin 2 is grid 1, pin 3 is the cathode, pin 4 is the heater, pin 5 is the heater, pin 6 is an internal connection, pin 7 is the plate, pin 8 is grid 3 and shield, and pin 9 is grid 2.
| Designation | Evidence | Confidence |
|---|---|---|
| E280F | 42 independent documents | confirmed |
Equivalence is asserted only where the archive's own literature states it directly, in at least 40 separate documents. Tubes that merely substitute in some circuits are not listed here.
Base B9A, viewed from below (the wiring side), pins numbered clockwise from the key. Read from the datasheet's basing table and checked against it automatically — confirm against the original datasheet before wiring.
| Measure | Per tube |
|---|---|
| Median | $221.72 |
| Typical range (25th–75th) | $132.00 – $270.69 |
| Most sales (10th–90th) | $50.00 – $295.17 |
| Extremes incl. outliers | $50.00 – $295.17 |
| Completed sales | 9 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| Valvo | $270.69 | $270.69 – $295.17 | 4 |
| Siemens | $168.27 | $114.81 – $221.72 | 4 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $221.72 | 8 |
Per-tube prices from completed sales, 2026-07-22 to 2026-09-23. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for 7722, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| CBS-Hytron | 7722 | PDF (59 KB) |
| Siemens | E280F | PDF (402 KB) |
| Philips | E280F | PDF (386 KB) |
Documents held here and used to write this page.
- S.Q. TUBE (filed under E280F)
- Maximum Ratings (Absolute maximum values)