6AQ4

6AQ4 is also designated EC91.

The 6AQ4 is a miniature triode with a coated unipotential cathode, contained in a T5-1/2 glass envelope with a miniature button 7-pin base, and designed for use as a grounded-grid amplifier at frequencies up to 250Mc/s.

Construction and Ratings

The tube has a maximum overall length of 2-1/8 inches, a maximum seated height of 1-7/8 inches, and a maximum diameter of 3/4 inch. Its mounting position is any. The basing diagram designation is 7DT, with connections as follows: Pin 1 Grid, Pin 2 Cathode, Pin 3 Heater, Pin 4 Heater, Pin 5 Cathode, Pin 6 Grid, Pin 7 Plate. The heater requires 6.3 volts at 0.3 ampere.

With an external shield connected to Pins 1 and 6, the plate-to-grid capacitance is 2.5 uuF, the plate-to-cathode-and-heater capacitance is 0.2 uuF, and the grid-to-cathode-and-heater capacitance is 8.5 uuF.

Maximum ratings include a plate voltage of 250 volts, a plate dissipation of 2.5 watts, a cathode current of 15 mamps, a voltage between heater and cathode of 150 volts, and a voltage between grid and cathode of 100 volts.

Characteristics

At a plate voltage of 250 volts and a grid voltage of -1.5 volts, the plate current is 10 mamps, the transconductance is 8500 micromhos, the plate resistance is 12000 ohms, and the amplification factor is 100. The equivalent noise resistance is 400 ohms.

The Mullard datasheet, which describes the EC91 as a miniature screened triode for use as a grounded grid amplifier, gives the same heater ratings, maximum ratings, and operating characteristics for the EC91, including an anode voltage of 250 V, grid voltage of -1.5 V, and cathode resistor of 150 ohms, with a transconductance of 8.5 mA/V, amplification factor of 100, anode resistance of 12000 ohms, and equivalent noise resistance of 400 ohms. The Mullard sheet gives the base as B7G and a maximum dimension of 19 mm.

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.

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.

Original manufacturer datasheets for 6AQ4, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• EC91 (filed under EC91)
• 6AQ4

2 further designations appear alongside 6AQ4 in the literature but below the evidence threshold used here, so they are not listed as equivalent.