In 1883 Edison discovered that electrons would flow in an evacuated lamp from a suspended filament. Years later> in 1905 Fleming expanded on Edison's discovery with his "Fleming Valve". But when Dr. Lee de Forest added a third component ‑ the grid ‑ to Fleming's Valve in 1907, he opened the door to the world of electronic amplification with the development of the vacuum tube.

Have you been bass amplifier shopping lately? If so, you probably noticed that many of the rear chassis panels have Speak-on Connectors included along with the traditional female 1/4" jacks. Excellent! Yeah! Woohoo! I digress. You've got to love the pro audio influence moving over into bass gear. It was bound to happen. Once bass amplification power amps started moving into the 500 watt and above range. As I remember, it was XYZ amplification that first started to use them, then is was the ABC Company and finally, everyone that is considered "Pro" is now incorporating them on their back panels. Why?