« Back
Moon by Simaudio 870A Stereo Power Amplifier

An extremely refined and powerful solid state amplifier by champions of clarity and finesse - Simaudio! The previous owner bought it from us and kept it in immaculate condition before trading it in for upgrades also by Simaudio. Comes with not only all original packaging and materials, but 6 years left on it's 10 year warranty! A great deal on unparalleled power! RETAIL: $20,000.

$12,999 USED (WITH 6 YEAR WARRANTY, in two-tone black/silver)

From Brian Mitchell on Ecoutics.com:

"Simaudio Ltd. introduced the Evolution Series MOON 870A Power Amplifier, a balanced differential dual-mono design providing 300 watts per channel into 8 ohms (600 watts into 4 ohms and 1200 watts into 2 ohms). The 870A replaces the MOON W-8, and uses proprietary MOON output transistors which the company claims provides tighter and more visceral bass performance, as well as unprecedented linearity thoughout the entire frequency spectrum. In addition the 870A takes advantage of a “zero global feedback” circuit, commonly referred to as Lynx.

Despite the 870A’s very high power rating, both transparency and soundstage are exceptional. Ultimately, this amplifier will mate seamlessly with, and drive virtually any loudspeaker to its full sonic potential. Of course, both RS-232 and 12 Volt triggers for custom-install environments are included as well as a plethora of user selectable cosmetic options that are available at the time of purchase.


Lynx circuitry which is a “no overall feedback” design resulting in genuine real-time amplification, a more accurate musical reproduction with respect to tonality, virtually non-existent intermodulation distortion and the elimination of common phase errors resulting from feedback
Proprietary MOON output transistors with unprecedented gain linearity resulting in improved bass response and even more accurate sonic reproduction – 16 per channel.
A massively oversized power supply
Custom proprietary toroidal transformer design with lower magnetic, electrical and thermal loss, yielding an improved power transfer and lower regulation factor. The result is increased current speed and better dynamics
A high damping factor yielding superior musical dynamics, improved signal speed and refined timbre accuracy
Stable to virtually any known speaker impedance
A very short capacitor-free signal path for a faster transient response
4-Layer PCB’s with pure copper tracings for a much shorter signal path
Full unsolicited RS-232 bidirectional feedback & 12 Volt trigger input/output for remote operation
Accurate matching of the very finest quality electronic components in a symmetrical circuit design
“Class A” output to 5 watts for greater efficiency
Ultra rigid chassis construction to minimize the effects of external vibrations"


Type Solid State
Configuration Dual-Mono / Balanced
Power Supply Transformers 2 x 1.3kVA
Power Supply Capacitance 240,000µF
Class Of Operation A/AB
Balanced Inputs XLR – 1 pair
Single-ended Inputs RCA – 1 pair
Input Device Type J-FETs
Input Impedance 47.5 KΩ
Input Sensitivity 1,400mV RMS
Output Device Type Bipolars – 16 per channel
Output Binding Posts WBT – 2 pair per channel
Output Power @ 8 Ω 300 Watts
Output Power @ 4 Ω 600 Watts
Output Power @ 2 Ω 1200 Watts
Output Power – Bridged Mono 1200 Watts
Frequency Response 10Hz – 200kHz (+0/-3dB)
Output Impedance < 0.01
Damping Factor (static) > 800
Gain 31dB
Signal-to-noise Ratio 106dB @ full power
Maximum Output Voltage 58 Volts
Slew Rate 42 V/µs
Maximum Current – Peak 72 amperes
Maximum Current – Continuous 30 amperes
Crosstalk @ 1kHz -105dB
IMD Unmeasureable
THD (20Hz – 20kHz @ 1 watt) 0.015 %
THD (20Hz – 20kHz @ 200 watts) 0.04 %
12 Volt Trigger Operation Direct Logic (0V = off, 12V=on) using a
1/8″ mini-jack with an input impedance of
1K Ω and current requirement of 12mA
RS-232 Port 9-pin female DB connector
Power Consumption @ idle 75 watts
AC Power Requirements 120V / 60Hz 240V / 50Hz
Fuse Replacement – 120V 10A long fast blow
Fuse Replacement – 230V 5A long fast blow
Shipping weight 98 lbs / 44 kgs
Dimensions (w x h x d) 18.75 x 7.5 x 17.5 in.