Thermionic vacuum valves, or tubes, are devices that are praised for their sonic performance when used in audio amplifiers. The exact causes for the natural, open and involving "tube sound" are still debated. One of the theories claims that electrons inside a tube travel from cathode to anode through vacuum in a straight line, while in transistors the path is zigzagged through silicone molecules; such twisted motion path reflects in the inferior audio performance of transistors. both statements are factual. Travel of electrons inside a transistor is probably not as obvious as in the tubes, but the effect of changing direction and electrons collisions are exposed through heat that gets generated. Tubes are not ideal for accurate reproduction of very low frequencies due to poor damping factor, nor for very high frequencies due to noise, but are ideal for reproduction of common sounds, such as human voice and the majority of musical instruments. The most acclaimed valve amplifier configuration is single ended design due to the simplest signal path; however, the design has inherent disadvantage of extremely high cost per produced watt of power. We prefer the balanced configuration of two single ended amplifiers that get summed up in the loudspeaker, as used in our valve powered loudspeakers.

Foundation #7: Thermionic vacuum tubes (valves) must be used for the amplification of human voice and the majority of instruments, in order to obtain the highest audio fidelity when the cost is of no concern. Power transistors must be used for reproduction of very low and very high frequencies, where they outperform the valves. Also, transistors must be used instead of the thermionic valves when the cost is a restriction.