KT120
KT120 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $63.97 per tube.
Description
The KT120 is a beam pentode power amplifier tube primarily designed for audio service, as described in the Tung-Sol datasheet. It uses a large wafer octal base with barriers and has an oxide coated, indirectly heated unipotential cathode. The tube may be operated in any mounting position.
Ratings
The KT120 has a plate dissipation rating of 60 watts and is designed for push-pull amplifier designs up to 200 watts output. Maximum DC plate voltage is 850 volts in tetrode connection and 650 volts in triode connection. Maximum DC grid 2 voltage is 650 volts in pentode connection and 600 volts in triode and ultralinear connection. Maximum DC grid 1 voltage is -200 volts. Maximum plate dissipation in pentode connection is 60 watts, and maximum grid 2 dissipation is 8.0 watts. Maximum cathode current is 250 mA in pentode connection and 230 mA in triode and ultralinear connection. Maximum grid 1 circuit resistance is 51,000 ohms for fixed bias and 240,000 ohms for self bias. Maximum bulb temperature is 250 degrees Celsius.
Electrical Characteristics
The heater is rated at 6.3 volts, with a current range of 1.7 to 1.95 amperes and an operating limit of 6.3 ± 0.6 volts. Maximum heater-cathode voltage is 300 volts with the heater negative with respect to the cathode (total DC and peak) and 200 volts with the heater positive. Maximum heater-to-cathode leakage current is 30 µA at a 300-volt heater-to-cathode difference. The basing diagram is JEDEC 7AC; pin 1 has no connection or is connected to the base shell. Grid 1 to plate capacitance is 1.8 pF, input capacitance is 29 pF, and output capacitance is 10 pF.
| Measure | Per tube |
|---|---|
| Median | $63.97 |
| Typical range (25th–75th) | $51.48 – $67.50 |
| Most sales (10th–90th) | $22.56 – $74.75 |
| Extremes incl. outliers | $22.56 – $74.75 |
| Completed sales | 9 |
| Brand | Median | Range | Sales |
|---|---|---|---|
| Tung-Sol | $63.97 | $51.48 – $67.50 | 9 |
| Condition | Median | Sales |
|---|---|---|
| current | $67.49 | 7 |
Per-tube prices from completed sales, 2026-08-05 to 2026-09-04. Matched pairs and quads are divided out. See the price index for how these move over time.
Original manufacturer datasheets for KT120, hosted by Frank Philipse's Electron Tube Data sheets.
| Manufacturer | Designation | Datasheet |
|---|---|---|
| Tung-Sol | KT120 | PDF (539 KB) |
Documents held here and used to write this page.
- **TUNG-SOL**