300B Loftin-White Power Amplifier by SOYA Susumu Part 2 【MJ’s DIY Amp Lab】

Delivers approximately 6W of output. A simple circuit design ensures excellent stability and sound quality.

Parts Used

The main components used in this amplifier are listed in Table 3, and as you can see, it’s constructed with a remarkably small number of parts. Only four vacuum tubes are used in total (see Photo 1). The brand doesn’t matter—just use what’s available. If possible, we recommend using new tubes with good emission.

[Table 3] List of Major Components

[Photo 1] Vacuum tubes used in this unit, from left: 300B EH (Electro-Harmonix), 6SL7GT (manufacturer unknown), and 5AR4 (Toshiba). The magnification of the photos varies.