Design Concept The schematics show you my concept in power amplifier design. I use the same tube for driver and output. I made PX4/PX4 SE power amplifier, RCA50/RCA50 SE power amplifier. Their tones are clear and powerful. Through listening, I discovered that the driver's tone contributes the greater part of the amplifier's voice. An excellent power tube demands a similar level of quality from its driver. Few driver tubes can sing along in beautiful harmony with a good power tube. I also made 300B push-pull/300B push-pull power amplifier. Before this I didn't have the impression that the 306B tone was very elegant. But the special tone of the 300B push-pull driver/300B push-pull output power amplifier taught me the true Western Electric sound.