6SF5 High Mu Triode Tube. Designed for service as a high gain audio-frequency amplifier and is especially useful in resistance-coupled amplifier circuits in AC or DC operated equipment. MFR: GE, Tung-Sol, Westinghouse,
Triode boost before 6SJ7
SM5CBW - Tubedata
Operating Points of Fi 2A3 / 3 Tube 3 Watt Direct Coupled Amplifier (Lipman) | diyAudio
Amplifier 3715 tube 6SF5 Ampl/Mixer Bell Sound Systems; | Radiomuseum
6sf5 tube 6sf5 metal tube | elliott electronic supply