Upgrade your amplifier setup with the finest electron tube ever made. The type 300B is made by hand in the USA using the original Western Electric specifications from 1938. Available in matched pairs, quad sets, and singles.

  • Category: Equipment



The 300B is known around the world for its sound quality and powerful performance in both single-ended & push-pull amplifiers.


We make the original 300B with authenticity and precision. Customers have trusted the same specs, materials, and testing standards for decades.

Moderate power, filamentary triodes for Class-A service.

Audio-frequency amplifier in positions where power outputs of approximately ten watts or less are required at relatively low plate voltages.

Dimensions, outline diagrams of the tubes and bases, and the arrangement of electrode connections to the base terminals are shown in Figures 1 and 2.

Base and Mounting
These vacuum tubes employ medium, four-pin thrust type bases suitable for use in Western Electric 143B or similar sockets. The 300B tube has the bayonet pin so located that it may also be mounted in a Western Electric 100M, 115B, or similar socket.

The tubes may be mounted in either a vertical or horizontal position. If mounted In a horizontal position, the plane of the filament, which is indicated In Figure 2, should be vertical.

Average Direct Interelectrode Capacitances
Grid to plate 15 µµf.
Grid to filament 9 µµf.
Plate to filament 4.3 µµf.

Filament Rating
Filament voltage 5.0 volts, a.c. or d.c.
Nominal filament current 1.2 amperes

The filaments of these tubes are designed to operate on a voltage basis and should be operated at as near the rated voltage as possible. When alternating current is used for heating the filament, the grid and plate returns should be connected to a center tap on the secondary of the filament transformer.

Matched Pair 6 800 ₪

Matched Quad 13 900 ₪

Single 3 700 ₪