WESTINGHOUSE 5654 6AK5 W TUBE 1950s NOTHING BETTER SOUNDING NOS NIB
5654 6AK5W. SPECIAL O GETTER WESTINGHOUSE 5654 pair. Very sweet music inside. I have a B&K 747 tube tester. This is a mutual conductance tester. I also use a Tektronix curve tracer for testing triodes.