ProLogue Seven

About the ProLogue Seven

The PrimaLuna ProLogue Seven is a vacuum tube monoblock power amplifier delivering 70 watts per channel from four KT88 output tubes in an ultralinear push-pull circuit, supported by two 12AX7 and two 12AU7 small-signal tubes per amplifier. Its dual-feedback topology combines cross-coupled current feedback with a small amount of global negative feedback to achieve low distortion, stable gain, and low output impedance. PrimaLuna's Adaptive AutoBias continuously monitors and adjusts output tube bias, compensating for tube aging, reducing distortion, and allowing use of various compatible power tube types without manual bias adjustment or matched pairs. A SoftStart circuit ramps voltages at power-up to extend tube life, and a tube-plate fuse protects the output stage. The ProLogue Seven uses custom wide-bandwidth output transformers, a toroidal power transformer, and point-to-point wiring in a hand-assembled chassis. It provides one RCA input, 2/4/8 ohm speaker taps, a frequency response of 20 Hz to 85 kHz (+/-0.5 dB), THD under 1% at full power, and an input sensitivity of 911 mV into 100 kilohms. Each monoblock measures 11 inches x 7.5 inches x 15.5 inches and weighs 37.5 lbs. The ProLogue Seven was widely regarded as a more powerful and refined alternative to the ProLogue Five stereo amplifier and is now a discontinued model from PrimaLuna's original ProLogue series.