46
46 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $49.90 per tube.
Description
The '46 is a double-grid power amplifier tube recommended especially for service in Class B amplifier circuits of suitable design. It has two grids, each terminating in its respective base pin. The filament is designed to operate at 2.5 volts and draws 1.75 amperes. The base is of the medium five-pin type, and the bulb is type S-17. The maximum overall length is 5-5/8 inches, and the maximum diameter is 2-3/16 inches.
Construction and Operation
For Class B operation, the two grids must be tied together. For Class A operation, the grid adjacent to the plate is connected to the plate, and the grid next to the filament serves as the control grid. The '46 can operate as a Class B amplifier with zero grid bias.
Ratings
For Class A operation, the plate voltage rating is 250 volts maximum. With the grid adjacent to the plate tied to the plate, the grid voltage is -33 volts, the plate current is 22 milliamperes, the plate resistance is 2380 ohms, the amplification factor is 5.6, and the mutual conductance is 2350 micromhos. The load resistance for maximum undistorted power is 6400 ohms, and the maximum undistorted power output is 1.25 watts.
For Class B operation with both grids tied together, the plate voltage can be 300 volts or 400 volts maximum, with the grid voltage at 0 volts. At 300 volts plate voltage, the plate current per tube is 4 milliamperes, the peak plate current per tube is 150 milliamperes, the load resistance per tube is 1300 ohms, and the maximum signal voltage per tube is 40 volts RMS. At 400 volts plate voltage, the plate current per tube is 6 milliamperes, the peak plate current per tube is 200 milliamperes, the load resistance per tube is 1450 ohms, and the maximum signal voltage per tube is 41 volts RMS. The maximum plate dissipation per tube is 10 watts. For two tubes, the maximum continuous power output is 16 watts at 300 volts plate voltage and 20 watts at 400 volts plate voltage.
Applications
The '46 is recommended for Class B audio power amplifier service. A pair of '46s in a Class B output stage can supply an exceptionally large amount of virtually undistorted power. A single '46 operated in the driver stage as a Class A amplifier can deliver sufficient power to drive a pair of '46s in the output stage; the intended application of the '46 as a Class A amplifier is for driving two '46s in a Class B amplifier circuit. The '46 was constructed for dual service to reduce the number of tube types necessary in a receiver. The datasheet text states that the bulb of the '46 may become very hot under certain conditions of operation and sufficient ventilation should be provided.
| Measure | Per tube |
|---|---|
| Median | $49.90 |
| Typical range (25th–75th) | $40.75 – $83.75 |
| Most sales (10th–90th) | $27.45 – $111.95 |
| Extremes incl. outliers | $16.57 – $147.95 |
| Completed sales | 23 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| RCA | $78.97 | $48.98 – $111.95 | 7 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $71.49 | 12 |
| used | $47.95 | 7 |
Per-tube prices from completed sales, 2026-02-12 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 46, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| Sylvania | 46 | PDF (91 KB) |
| RCA | 46 | PDF (84 KB) |
| Tung-Sol | 46 | PDF (44 KB) |
Documents held here and used to write this page.
- DUAL-GRID POWER AMPLIFIER