6BA6

6BA6 is also designated EF93. Completed sales put the typical price at $9.86 per tube.

Description

The 6BA6 is an indirectly-heated variable-mu RF pentode, mounted in a standard T5½ bulb and fitted with a B7G standard base. It has an indirectly-heated oxide-coated cathode.

Construction and Ratings

The heater is rated at 6.3 volts and 0.3 amperes, and is intended for operation in parallel with other valves in AC-operated equipment. The maximum DC heater-cathode potential is 250 volts. Maximum ratings are 300 volts for anode voltage, 125 volts for screen voltage, and 300 volts for screen supply voltage. Maximum dissipations are 3.0 watts for the anode and 0.6 watts for the screen. The tube has a maximum overall length of 2-1/8 inches, a maximum diameter of 3/4 inches, and a maximum seated height of 1-19/32 inches (excluding tip).

Base connections are: Pin 1 Control Grid, Pin 2 Suppressor and Internal Shield, Pin 3 Heater, Pin 4 Heater, Pin 5 Anode, Pin 6 Screen, Pin 7 Cathode.

Characteristics

With an anode voltage of 250 volts, screen supply voltage of 250 volts, series screen resistor of 33,000 ohms, screen voltage of 100 volts, grid voltage of -1 volt, and cathode bias resistor of 68 ohms, the mutual conductance is of the order of 4 mA/V. Under the same conditions, the datasheet gives an anode current of 11 mA, screen current of 4.2 mA, anode impedance of 1.5 megohms, inner amplification factor of 21.0, and equivalent noise resistance of 3,650 ohms. Input impedance under these conditions is 4,500 ohms at 45 Mc/s and 900 ohms at 90 Mc/s.

Capacitance values, when pentode connected with no external shield, are approximately 5.5 pF input, 5.0 pF output, and a maximum grid-anode capacitance of 0.0035 pF. For grounded grid operation with no external shield, the approximate values are 6.0 pF input, 5.6 pF output, and 0.01 pF anode-cathode capacitance.

Applications

The 6BA6 is designed for use as an RF or IF amplifier. It is efficient as an IF amplifier using intermediate frequencies around 10 Mc/s, and can be used as a grounded grid amplifier at frequencies of the order of 100 Mc/s. The datasheet states that a stage gain of 44 times can be expected when used as an IF amplifier with a total bandwidth of 200 Kc/s for 3 db down, with IF coils of Q 70 and tuning capacity 50 pF. It may also be used as an RC coupled amplifier for small inputs.

When the valve is used as an RF or IF amplifier, the suppressor grid and internal shield should be connected to the cathode at the socket. For very high frequency applications, it is advisable that grid bias be applied to the control grid and suppressor grid simultaneously, the control grid being biased to a value of approximately 2.5% of that applied to the suppressor grid.

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.

Same design, different filament voltage. Not interchangeable with 6BA6: 12BA6.

Base B7G, viewed from below (the wiring side), pins numbered clockwise from the key. Read from the datasheet's basing table and checked against it automatically — confirm against the original datasheet before wiring.

Per-tube prices from completed sales, 2026-08-30 to 2026-09-21. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 6BA6, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• BRIMAR
• **EF93** (filed under EF93)