6CG7
6CG7 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $15.47 per tube.
The 6CG7 is a miniature medium-mu twin triode intended for general-purpose amplifier and oscillator applications. It is housed in a T-6½ glass envelope and uses an E9-1 Small Button 9-Pin base (RETMA 9AJ). The tube is electrically equivalent to the 6SN7-GTB.
Construction
Each section of the 6CG7 comprises a plate (pins 1 and 6), a grid (pins 2 and 7), and a coated unipotential cathode (pins 3 and 8). Pin 9 connects to an internal shield. The heater is connected to pins 4 and 5. The 6CG7 has a heater rating of 6.3 volts at 0.6 amperes; an 8CG7 variant, identical except for heater ratings, operates at 8.4 volts and 0.45 amperes. Both types have a controlled heater warm-up time of 11 seconds, suited for television receivers with series-connected heaters.
Ratings
Design-center values for each section in Class A1 amplifier service include a maximum DC plate voltage of 300 volts, a plate dissipation of 3.5 watts per plate, and a total plate dissipation of 5.0 watts for both plates. Maximum DC cathode current is 20 milliamperes, with a peak cathode current of 300 milliamperes. Maximum heater-to-cathode voltage is 100 volts DC (positive), 200 volts total DC and peak (positive or negative). Maximum grid-circuit resistance with fixed bias is 1.0 megohm. For vertical-oscillator service, the maximum DC plate voltage is 300 volts and peak negative grid voltage is 400 volts; for horizontal-oscillator service, the corresponding values are 300 volts DC plate and 600 volts peak negative grid.
Characteristics
At a plate voltage of 250 volts and grid voltage of −8.0 volts per section, the amplification factor is 20, plate resistance is approximately 7700 ohms, transconductance is 2600 micromhos, and plate current is 9.0 milliamperes. At the same plate voltage and a grid voltage of −12.5 volts, plate current is 1.3 milliamperes. The grid voltage required for a plate current of 10 microamperes is approximately −18 volts. Direct interelectrode capacitances per section are approximately 4.0 μμf (grid to plate), 2.3 μμf (input), and 2.2 μμf (output).
| Measure | Per tube |
|---|---|
| Median | $15.47 |
| Typical range (25th–75th) | $9.19 – $23.60 |
| Most sales (10th–90th) | $5.50 – $38.99 |
| Extremes incl. outliers | $1.53 – $193.57 |
| Completed sales | 213 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| RCA | $18.00 | $12.72 – $28.48 | 80 |
| GE | $15.73 | $8.45 – $18.50 | 34 |
| Sylvania | $14.18 | $8.99 – $16.34 | 25 |
| Raytheon | $20.78 | $12.50 – $36.48 | 21 |
| Tung-Sol | $20.50 | $15.99 – $31.99 | 6 |
| Amperex | $17.35 | $12.69 – $25.00 | 4 |
| Condition | Median | Sales |
|---|---|---|
| NOS | $18.90 | 97 |
| used | $13.47 | 87 |
Per-tube prices from completed sales, 2026-07-17 to 2026-10-17. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for 6CG7, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| General Electric | 6CG7 | PDF (460 KB) |
| Tung-Sol | 6CG7 | PDF (167 KB) |
Documents held here and used to write this page.
- 6CG7-8CG7