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300B Triode Tubes

The 300B is a directly heated power triode that Western Electric introduced for telephone amplification. Today it powers many single-ended amplifiers, valued for simple circuits in which a single tube drives a matched output transformer at low power.

John Makovsky

John Makovsky

Audio

Layer GEN-300B – Single-Ended Class A Tube Amplifier

Layer Audio Design has introduced the GEN-300B integrated amplifier, built around a single-ended Class A tube topology and designed for use with both headphones and high-sensitivity loudspeakers. Its fully discrete signal path employs two 6N8P driver tubes, a pair of directly heated 300B output triodes, and a 5AR4 rectifier tube. The rated output power is up to 10 watts per channel into an 8-ohm load, while separate 4- and 8-ohm speaker outputs are provided.
Stas Ustenko

Stas Ustenko

Audio

The Best 300B Single-Ended Amplifiers of 2026

Seven single-ended 300B amplifiers: rated specifications, circuit solutions, speaker compatibility calculations and impedance requirements.

Hifiverse Editorial Team

Audio

Western Electric 91E Review – Tube Euphoria

By resuming the introduction of 300B tubes, Western Electric has created a full-scale storm on the audiophile market. Well, the American manufacturer has many more things in its arsenal that can surprise fans of good sound – for example, the Western Electric 91E integrated single-ended amplifier, which we are testing today.

What the 300B tube is & why it matters

A single 300B in single-ended operation gives roughly six to eight watts, and a push-pull pair reaches about twenty. The anode can dissipate 40 W, so a good tube runs for years at moderate settings. Low power sets strict demands on loudspeakers, and high-sensitivity horns or wideband drivers suit these amplifiers best. Choosing a speaker for a 300B design starts with its sensitivity and impedance curve.

What you'll find in this tag

The tag combines product news and an in-depth buyer's guide. Launch stories present new integrated amplifiers from Layer Audio Design and Western Electric. A long article compares seven single-ended 300B models with rated specifications, circuit solutions and calculations of speaker compatibility. The guide pairs that hardware with a method for matching speakers.

Key amplifiers & brands to know

Layer GEN-300B - an integrated with single-ended Class A topology and 10 W per channel. Western Electric 91E - a single-ended integrated from the company that restarted production of its own 300B tubes. The seven-model guide adds designs from several workshops and explains how their output stages, driver tubes and power supplies differ from one another.

Related topics & where to go next

Read on in Tube (Valve) Hi-Fi, Single-Ended Amplifiers and Class A Amplification. Horn Loudspeakers and Speaker and Amplifier Matching help pick partners for a low-power triode amplifier.