6J7
6J7 is also designated 6J7G, 6J7GT. Completed sales put the typical price at $14.64 per tube.
The 6J7 is a heater-cathode type pentode amplifier tube with a sharp cut-off characteristic, housed in an MTT-8 metal shell envelope with a B7-22 small wafer octal 7-pin phenolic base and a top cap for grid number 1. It has a coated unipotential cathode and is designed for service as a biased detector or high-gain amplifier.
Construction and Ratings
The heater requires 6.3 volts (AC or DC) at 0.3 ampere. The pinout is: pin 1 shell and internal shield, pin 2 heater, pin 3 plate, pin 4 grid number 2 (screen), pin 5 grid number 3 (suppressor), pin 7 heater, and pin 8 cathode. The tube can be mounted in any position. The maximum d-c heater-cathode voltage is 100 volts.
Characteristics
In pentode connection with 250 volts plate voltage, the plate resistance is over 1.0 megohm, the transconductance is 1225 micromhos, and the grid bias for cathode-current cutoff is -77 volts. With 100 volts plate voltage in pentode connection, the plate current is 2.0 milliamperes and the screen current is 0.5 milliampere. In pentode connection, the plate dissipation is 0.83 watts and the screen dissipation is 0.11 watt.
In triode connection with 250 volts plate voltage, the amplification factor is 20, the plate resistance is 0.0105 megohm, the transconductance is 1900 micromhos, and the plate current is 6.5 milliamperes. In triode connection, the plate dissipation is 1.93 watts.
Capacitances
Direct interelectrode capacitances in triode connection are: grid to plate 0.005 μμf, input 5 μμf, and output 14 μμf. In pentode connection, the direct interelectrode input capacitance is 7 μμf and the output capacitance is 12 μμf.
Equivalents
The electrical ratings and characteristics of the 6J7 are the same as those of the 6J7-G, 6J7-GT, and 6C6, except for capacitances.
| Designation | Evidence | Confidence |
|---|---|---|
| 6J7G | 51 independent documents | confirmed |
| 6J7GT | 51 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.
| Measure | Per tube |
|---|---|
| Median | $14.64 |
| Typical range (25th–75th) | $8.18 – $27.43 |
| Most sales (10th–90th) | $5.75 – $40.67 |
| Extremes incl. outliers | $0.12 – $104.06 |
| Completed sales | 30 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| Sylvania | $13.62 | $11.70 – $23.00 | 3 |
| Tung-Sol | $22.75 | $8.18 – $27.45 | 3 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $14.24 | 8 |
| used | $18.74 | 9 |
Per-tube prices from completed sales, 2026-07-05 to 2026-09-30. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for 6J7, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| General Electric | 6J7 | PDF (208 KB) |
| Tung-Sol | 6J7 | PDF (169 KB) |
| RCA | 6J7 | PDF (84 KB) |
| RCA | 6J7 | PDF (76 KB) |
| Sylvania | 6J7 | PDF (74 KB) |
| AWV | 6J7G | PDF (493 KB) |
| Brimar | 6J7G | PDF (69 KB) |
| Sylvania | 6J7GT | PDF (109 KB) |
Documents held here and used to write this page.
- 6J7GT (filed under 6J7GT)
- RADIOTRON (filed under 6J7G)
- **Description and Rating**
5 further designations appear alongside 6J7 in the literature but below the evidence threshold used here, so they are not listed as equivalent.