The MOON 850P is the most advanced MOON preamplifier to date.

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Extensive research and development, coupled with recent advancements in electronic parts have provided us with the foundation to design what may very well be the transparent, quietest, most accurate and uncolored preamplifier. Targeted to the discerning listener who desires uncompromising musical reproduction, the 850P features numerous proprietary technologies.

Our M-Octave Damping damping system that eliminates the sonically degrading effects of microphonics by mounting the main audio circuit on an 8-point floating suspension. The result is a more natural, liquid and lifelike sound. Since listening environments are typically loaded with acoustically induced vibrations that originate from the loudspeakers, we use M-Octave to isolate the 850P from these microphonic-causing vibrations, allowing you to hear more music, exactly the way it was recorded. 

Other in-house technologies include (i) i²DCf power supply voltage regulation, (ii) M-Ray volume control, with a phenomenal 530 steps, allowing for an extremely precise level adjustment, (iii) SimLink and (iv) M-Lock, just to name a few, as well as an RS-232 connection, IR port and 12 Volt triggers for custom-install environments.

User manual Product details Comparison chart

Technical aspects

2-chassis design with one chassis housing the power supply, digital controller circuitry and software processing. The other chassis contains the audio circuitry
The preamplifier's audio section is located on its own dedicated circuit board, which is mounted to the chassis with our M-Octave Damping system
A dual-mono oversized power supply using 2 toroidal transformers in conjunction with 6 stages of DC voltage regulation and extensive choke filtering
M-Ray volume control based on the R-2R resistor array configuration using metal film surface mount resistors with 0.1% tolerances, resulting in no sonic degradation of the audio signal, regardless of the selected volume setting
Power supply voltage regulation includes i²DCf (Independent Inductive DC Filtering); There is one inductor dedicated to each integrated circuit type component (DAC, Op-Amp, etc.) in the audio circuit's signal path; 40 stages in all
Fully differential, no global feedback circuit topology, using absolutely no capacitors anywhere in the audio signal path
M-Lock for "user selectable" maximum volume setting lock-out for each line input
"Gain offset" for each individual line input with a ±10dB range
Each line input is fully configurable to be "home-theater ready", where the gain section of the 850P is bypassed
RS-232 port for (i) full unsolicited bidirectional feedback and (ii) firmware updates
IR input for external control
12 Volt trigger output for remote operation
SimLink™ controller port for 2-way communications with other compatible MOON components
4-Layer printed circuit boards with pure copper tracings for a much shorter signal path; This results in greater sonic accuracy and a dramatically improved signal-to-noise ratio
Ultra rigid chassis construction to minimize the effects of external vibrations
Accurate matching of the very finest quality electronic components in a symmetrical circuit design
Includes FRM-3 remote control

Magazine reviews

 SoundStage! Ultra  (www)  Jeff Fritz  January 2016
 Stereophile   (USA)  Brian Damkroger  December 2013  
 TONEAudio  (www)  Jeff Dorgay  June 2013 - # 55
 PRO High-End  (Russia)  Vladimir P.  April 2013  #14
 HIFI live   (Spain)   José Manuel Delgado  April 2012
 hi-fi+   (United Kingdom)  Roy Gregory  March 2012   #87


 Recommended Reference  SoundStage!  (www)  February 2016
 Reviewer's Choice  SoundStage!  (www)  January 2016
 Editors' Choices  Stereophile  (USA)  December 2014
 2014 Product of the Year: Finalist  Stereophile  (USA)  December 2014
 Recommended Components  Stereophile  (USA)  April 2014
 2013 Preamplifier Product of the Year  TONEAudio  (USA)  January 2014  #51
 Maxima Calidad  (High Quality)  HIFI live  (Spain)  April 2012