One ElectronOne Electron chokes and transformers are designed by John Atwood, to fill the need for high-quality yet affordable audio transformers and chokes that are not normally available elsewhere.
Transformer - One Electron, Output, 3000 Ω to 16/8/4 Ω
The UBT-3 from One Electron is the same size and power (15 watts) as the UBT-1, but has a primary impedance suitable for single or paralleled tubes running at B+ voltages of 300 to 400 volts, such as: 2A3, WE 300B, 50, etc.
Transformer - One Electron, Output, 1600 Ω to 16/8/4 Ω
The UBT-1 from One Electron is a low-impedance single-ended output transformer intended for parallel combinations of tubes running a B+ voltages of 250 to 325 volts, such as: two or three EL34s (triode connected), three 2A3s, two 300Bs, two 6AS7s, etc., as well as single sweep tubes run in 'enhanced-triode' mode, resulting in 10 to 15 watts of output power.