5879

5879 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $11.04 per tube.

The 5879 is a sharp-cutoff pentode of the 9-pin miniature type, intended for use as an audio amplifier in applications requiring reduced microphonics, leakage noise, and hum. It is especially useful in the input stages of medium-gain public address systems, home sound recorders, and general-purpose audio systems.

Construction

The 5879 uses a noval 9-pin socket, which may be mounted to hold the tube in any position. Pin 1 is grid No. 1, pin 3 is the cathode, pins 4 and 5 are the heater, pin 7 is grid No. 2, pin 8 is the plate, and pin 9 is grid No. 3. Pins 2 and 6 have no connection, and it is recommended that these pins be grounded in all applications. Grounding pins 2 and 6 effectively shields grid No. 1 and the plate from the heater and helps to reduce hum level when an ac heater supply is used.

Ratings

The heater requires 6.3 volts AC or DC at 0.150 ampere. In pentode connection, the maximum plate voltage is 300 volts, the maximum grid-No.2 voltage is 150 volts, and the maximum grid-No.2 supply voltage is 300 volts. The maximum negative bias value for grid-No.1 voltage is 50 volts, and the maximum positive bias value is 0 volts. The peak heater-cathode voltage is 90 volts maximum, whether the heater is negative or positive with respect to the cathode. The maximum grid-No.1-circuit resistance is 2.2 megohms.

In triode connection, with grids No. 2 and No. 3 connected to the plate, the maximum plate voltage is 250 volts, the maximum total plate dissipation is 1.5 watts, and the maximum negative and positive bias values for grid-No.1 voltage are 50 volts and 0 volts, respectively. The peak heater-cathode voltage in triode connection is also 90 volts maximum in either polarity.

Capacitances

With no external shield, in pentode connection, the grid-No.1-to-plate capacitance is 0.11 μμf maximum, the input capacitance is 2.7 μμf, and the output capacitance is 2.4 μμf. In triode connection with grids No. 2 and No. 3 connected to the plate, the grid-No.1-to-plate capacitance is 1.4 μμf, the grid-No.1-to-cathode capacitance is 1.4 μμf, and the plate-to-cathode capacitance is 0.85 μμf.

Characteristics

In pentode connection, with a plate voltage of 250 volts, grid No. 3 connected to the cathode, and a grid-No.2 voltage of 100 volts, the plate resistance is approximately 2 megohms, the transconductance is 1000 μmhos, the plate current is 1.8 milliamperes, and the grid-No.2 current is 0.4 milliampere.

In triode connection with grids No. 2 and No. 3 connected to the plate, the amplification factor is 21 at both 100 and 250 volts plate voltage. At 100 volts plate voltage, the plate resistance is approximately 17000 ohms, the transconductance is 1240 μmhos, and the total plate current is 2 milliamperes. At 250 volts plate voltage, the plate resistance is approximately 13700 ohms, the transconductance is 1530 μmhos, and the total plate current is 5 milliamperes.

Mechanical

The maximum overall length is 2-3/16 inches, the maximum seated length is 1-15/16 inches, and the maximum diameter is 7/8 inch.

Per-tube prices from completed sales, 2026-06-23 to 2026-09-16. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 5879, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• SHARP-CUTOFF PENTODE