MOON 850P Reference PreamplifierState of the Art Dual Chassis Reference Balanced Preamplifier, the MOON 850P is the most advanced MOON preamplifier, this is the Holy Grail of analogue audio design. Extensive research and development during design, coupled with recent advancements in electronic parts and a move to further in house manufacturing have allowed the MOON team the opportunity to keep the 850P at the top of the ladder in the pure analogue sector of the high end hifi market.