Conrad Johnson D250S

The conrad-johnson Enhanced Triode (ET) Amplifiers are power amplifiers designed to capture the best attributes of both fine vacuum-tube designs and of the best solid-state designs. ET250S amplifier in nice condition.   The ET250S is a 250-watt per channel stereo power amplifier, the MET150 a five-channel amplifier rated at 150 watts per channel. These sophisticated zero-feedback amplifiers offer the refinement of a vacuum-tube amplifier with the guts and control of a solid-state amplifier.
Zero Feedback. Negative feedback is an engineering technique used to reduce measured distortion. While feedback does achieve this goal, it also introduces aberrations in the tran­sient response characteristics of the circuit. We have found that eliminating loop negative feedback can result in much finer gradations in dynamic response (micro-dynamics) and more accurate decay on musical transients. But eliminating negative feedback requires much more care in the design of the circuits—both in choosing devices and in power-supply design—and places greater demands on the parts.