Think of the REX II as two single-ended amplifiers per channel, with their waveforms summed at the output transformer. No direct current flows through the latter, allowing the output transformer to be a truly wide-bandwidth design while reducing low-frequency distortion. REX II extends the benefits of vacuum-tube current sources to include both the first and second gain stages of the circuit design. Hence, the linearity of the gain stage improves, the adjustments for the first and second gain stages become independent, and the tube current source components operate at a lower stress level. You can also fine-tune the sound to best meet your individual needs