(Otomono Lab) OTOMON 205D/2A3/300B Compatible SE Vacuum Tube Amplifier, Non-Feedback. This amplifier is compatible with three types of vacuum tubes, allowing you to enjoy various sounds and timbres. It outputs 5W (THD: 5%) when using 300B vacuum tubes. With low voltage and constant current specifications, you can use valuable 300Bs such as Western Electric and Takatsuki for a long lifespan. Designed for full-range and field coil speakers, it is also ideal for speakers with high sensitivity. Although it's a 5W maximum amplifier, 2A3 and 205D have low output, so speakers with a sensitivity of 92dB or higher are recommended. This is a non-feedback amplifier. With a hum level of less than 0.2mV, there is no noise or hum even when used with a horn system. The 717A is used in the driver stage, and 80/83/274A can be used interchangeably as the rectifier tube. The output tubes can be switched between 205D/2A3/300B with a switch. Alternatively, modern Psvane 205D to Western Electric WE 205D can be used without any problems. Before listing, the amplifier was inspected by the manufacturer (Otomono Lab) and returned to a like-new operational state. As it is a used item, there are scratches and dirt on the transformers, but it is generally in a clean condition. The manufacturer's warranty is 3 months. Otomono is a Japanese manufacturer. The manufacturer's HP is https://otomon.net. Please access the website for more information. Vacuum tubes used: First stage tube: 717A Output tube: 205D/2A3/300B Rectifier tube: 80 (83, 5Z3, 274A, etc. can be used, but the voltage will be slightly higher) Vacuum tubes are not included and must be provided by the winning bidder. Specifications: (Measured by the manufacturer) Frequency response: 30Hz ~ 18KHz Residual noise: 0.2mV or less Size: W400 x D285 x H230mm THD: Output and distortion rate (8Ω) 205D: 1.6W (5%) 2A3: 3.5W (5%) 300B: 5W (5%) This is a non-feedback amplifier with no hum or noise, and the sound is clear and musically excellent. Recommended for high-sensitivity horn systems.