6DA6

6DA6 is also designated EF89. Completed sales put the typical price at $20.50 per tube.

Description

The 6DA6 is an R.F. pentode with variable transconductance for use as an amplifier. It has a coated unipotential cathode and a small button noval 9-pin base.

Construction and Mounting

The 6DA6 has a maximum overall length of 2-13/32 inches, a maximum seated height of 2 5/32 inches, and a bulb length excluding tip of 1 25/32 inches ± 3/32 inch. It can be mounted in any position. The basing is JETEC designation 9BA. Pin 1 and pin 6 are internal shields; pin 2 is Grid No.1; pin 3 is the cathode; pins 4 and 5 are the heater; pin 7 is the plate; pin 8 is Grid No.2; and pin 9 is Grid No.3.

Ratings

The heater requires 6.3 volts at 0.2 ampere. Maximum ratings include a plate voltage of 300 volts (550 volts without current), a plate dissipation of 2.25 watts, a Grid No.2 voltage of 300 volts (550 volts without current), a Grid No.2 dissipation of 0.45 watt, a cathode current of 16.5 milliamperes, a Grid No.1 circuit resistance of 3 megohms, a Grid No.3 circuit resistance of 10,000 ohms, and a maximum voltage between heater and cathode of 100 volts.

Capacitances

Grid No.1 capacitance to all other elements is 5.5 μμF; plate capacitance to all other elements is 5.1 μμF. Plate to Grid No.1 capacitance is 0.002 μμF maximum, and Grid No.1 to heater capacitance is 0.05 μμF maximum.

Typical Characteristics

Typical operating points include a set with plate voltage 250 V, Grid No.2 voltage 100 V, Grid No.3 voltage 0 V, plate current 9 mA, Grid No.1 voltage -2 V, Grid No.2 current 3 mA, transconductance 3600 micromhos, plate resistance 1 megohm, and amplification factor of Grid No.2 with respect to Grid No.1 of 19. Another set has plate voltage 250 V, Grid No.2 voltage 85 V, plate current 9 mA, Grid No.1 voltage -1 V, Grid No.2 current 3.2 mA, transconductance 4000 micromhos, and plate resistance 0.8 megohm minimum. A further set has plate voltage 170 V, Grid No.2 voltage 100 V, plate current 12 mA, Grid No.1 voltage -1 V, Grid No.2 current 4.4 mA, transconductance 4400 micromhos, and plate resistance 0.3 megohm minimum.

Applications

The 6DA6 is intended for use as an R.F. or I.F. amplifier. Operating characteristics for such use include a supply voltage of 250 V, plate voltage 250 V, Grid No.3 voltage 0 V, Grid No.2 series resistor 51,000 ohms, cathode resistor 160 ohms, Grid No.1 bias -1.95 V, plate current 9 mA, Grid No.2 current 3 mA, transconductance 3500 micromhos, plate resistance 1 megohm, and equivalent noise resistance 4200 ohms. Another R.F. or I.F. amplifier set uses a supply voltage of 200 V, plate voltage 200 V, Grid No.2 series resistor 24,000 ohms, cathode resistor 130 ohms, Grid No.1 bias -20 V, plate current 11.1 mA, Grid No.2 current 3.8 mA, transconductance 3850 micromhos, plate resistance 0.6 megohm, and equivalent noise resistance 4200 ohms. The 6DA6 is also intended for use as an A.F. amplifier.

Notes from the Philips datasheet describe the 6DA6 as a pentode with variable mutual conductance for R.F. or I.F. amplifier use, with an indirectly heated cathode for A.C. or D.C. parallel supply. In one typical characteristic setting, control grid current may occur, and if not permissible the negative grid bias should be increased to at least 1.5 V.

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.

Per-tube prices from completed sales, 2026-07-07 to 2026-09-18. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 6DA6, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• 6DA6
• HILIPS EF89 (filed under EF89)