What is triode, pentode or tetrode?
A triode is the description given to the type of tube utilised and refers to the amount of elements it has, which for a triode it has three, a Cathode, Anode and Grid. A tetrode has four elements, a Cathode, Anode, Grid and Screen Grid. A pentode has five elements, a Cathode, Anode, Grid, Screen Grid and Suppressor Grid. TT prefers pentodes in output stages as these extra grids stop the problem of secondary emission of electrons. This happens when electrons that have been emitted from the cathode bounce back and get re-emitted a problem with triode power tubes. What is single ended, parallel single ended and push-pull. Single ended means the amplifier tubes are operated in a single ended mode, the audio signal goes in one end of the tube and re-appears at the other end, very simple but it has its drawbacks because of increased distortion and noise problems. Parallel single-ended is the same thing but instead of one tube, more a used together in a daisy chain fashion. Push-Pull is the p
