EL509/6KG6 is a beam power tetrode intended for use in Class A, AB, or B audio amplifiers and for Class B or C RF amplification. Close manufacturing specification tolerances and improved high voltage processing provides improved reliability and superior performance. The EL509/6KG6 features: Increased peak cathode emission from new cathode materials Stable operation from extended processing and aging Gold-plated gridPrecise grid/screen alignmentExtra-heavy glass envelope for ruggednessImproved vacuum processingComprehensive testing before and after aging