6BE6

6BE6 is also designated 5750, EK90. Completed sales put the typical price at $9.26 per tube.

The 6BE6 is a pentagrid valve having a single electron stream but with an oscillator or injector grid and a control or signal grid. It has an indirectly-heated oxide-coated cathode and is mounted in a standard T5½ bulb, based with a BVA standard base type B7G.

Construction and Ratings

The heater voltage is 6.3 volts and the heater current is 0.3 amperes. Maximum total cathode current is 14 mA. Maximum overall length is 2-1/8 inches, maximum diameter is 3/4 inches, and maximum seated height (excluding tip) is 1-19/32 inches. The base type is B7G. Pin 1 is the oscillator grid (grid 1); pin 2 is the cathode and suppressor (grid 5); pins 3 and 4 are the heater; pin 5 is the anode; and pin 6 is the screen grids (grids 2 and 4).

Applications

The valve may be used with a separate oscillator or in a self-oscillator circuit up to frequencies of the order of 100 Mc/s. It may be employed at such frequencies as a self-excited oscillator. When used under self-excited oscillator conditions, the oscillator coil design is somewhat critical. The use of A.V.C. is not advised when the valve is employed at high frequencies of the order of 30 Mc/s and above; at frequencies in the region of 100 Mc/s, A.V.C. is not advised because appreciable grid current may appear on the control grid. A.V.C. may be applied to the control grid, but the DC resistance between control grid and chassis should preferably not exceed 1 megohm.

The screen voltage employed is not very critical but, in general, best results are obtained with a voltage between 70 and 100 volts. It is preferable to supply the screen voltage from a potentiometer rather than a series resistor; a potentiometer supplying this valve and the IF amplifier should employ such values that the lower limb consumes a fixed drain of approximately 5 to 10 mA. As normally employed, the input resistance is negative, and a stopper resistance in the control grid is frequently essential to avoid instability.

The valve is quite suitable for use as an AF mixer, as it has two grids capable of controlling the anode current. When used in volume expander applications, grid 3 should be used for control purposes. The value of oscillator grid current preferably should not be less than 0.2 mA and in no case less than 0.16 mA if operation is to be reliable with low mains voltages. To avoid modulation hum and microphonics, the heater should be operated at cathode potential. The peak voltage between cathode and earth should not in general be less than 1.5 volts or oscillation may be unreliable.

At VHF the input impedance varies considerably with circuit constants and layout; no value can be quoted reliably. The capacity change at VHF is of the same order as that at 18 Mc/s. Characteristic curves show the variation in conversion conductance and anode impedance with several values of screen voltage, and curves show the relationship between the oscillator frequency and the voltage applied to the control grid, the relationship between the oscillator frequency and the line voltage applied, and the frequency drift of the oscillator plotted against time. The report containing these characteristics details the valve's use as a frequency changer in superheterodyne receivers.

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.

Per-tube prices from completed sales, 2026-02-06 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 6BE6, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• Finish Start a Good C
• **EK90** (filed under EK90)
• PENTAGRID CONVERTER (filed under 5750)

2 further designations appear alongside 6BE6 in the literature but below the evidence threshold used here, so they are not listed as equivalent.