4X150A

4X150A is also designated 7034. Completed sales put the typical price at $18.60 per tube.

The 4X150A is a radial-beam power tetrode intended for use as an amplifier, oscillator, or frequency multiplier over a wide range of frequencies extending into the UHF region. It is cooled by forced air.

Construction

The cathode is internally connected to the four even-numbered base pins. The anode-cooler assembly provides a terminal surface for the plate connection. The tube may be mounted in any position. It will fit a standard loktal socket, but the use of such a socket prevents adequate air-cooling of the base of the tube.

Ratings and Operating Conditions

The maximum rated plate voltage is 1250 volts, although the tube is capable of good performance with plate voltages as low as 400 volts. The maximum-rated plate dissipation is 150 watts; for plate-modulated applications, the maximum-rated plate dissipation is 100 watts under carrier conditions. Plate dissipation may be permitted to exceed the maximum rating momentarily, as during tuning. The heater should be operated as close to 6.0 volts as possible, but it will withstand heater-voltage variations as great as 10% without injury.

Cooling Requirements

The use of the Eimac 4X150A Air-System Socket, or a socket providing equivalent air-cooling facilities, is required. Sufficient forced-air cooling must keep the cooler core and the metal parts of the metal-to-glass seals from exceeding a maximum temperature of 150°C. Seven and one-half cubic feet of cooling air per minute must flow through the Air-System Socket and the anode cooler for adequate cooling. The total pressure drop through the socket and the anode cooler is 0.6 inches of water.

Applications

A single 4X150A operating in a coaxial-cavity amplifier circuit will deliver up to 140 watts of useful power output at 500 megacycles, according to the Eitel-McCullough datasheet. The same datasheet states that at 500 Mc. as much as 30 watts driving power may be required in ordinary circuits. In class-A and -AB1 amplifiers, where no grid current flows, the grid-bias voltage may be applied through a resistor; the maximum permissible grid-bias series resistance per tube is 100,000 ohms. Plate modulation can be applied when the tube is operated as a class-C radio-frequency amplifier; to obtain 100% modulation, the d-c screen voltage must be modulated approximately 55%, in phase with the plate modulation. Satisfactory operation in stable amplifier circuits is indicated by d-c grid-current values below approximately 15 milliamperes. The transconductance is measured at E_b = 500v, E_c2 = 250v, I_b = 200 ma.

Related Types

The Eitel-McCullough datasheet states that the type 4X150A is identical to 4X150D except for the heater rating of 26.5 volts.

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, 2026-06-21 to 2026-08-29. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 4X150A, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• TECHNICAL DATA (filed under 7034)
• EITEL-McCULLOUGH, INC.