SIMAUDIO Moon Evolution 870A


Power amplifiers

Both the 740P and 870A represent great value components – for the price you pay the sound of this combo is unbeatable. Simaudio offers 10 year warranty with their products which also screams of the confidence in their own products. Add rugged build and impeccable finish and the Moon Evolutions turn to be among the finest pieces of audio available today.

100% reference

Function and form

Ease of use

The 44kg Simaudio Moon Evolution 870A is not just an amplifier – it is a very powerful amplifier, delivering 2x300W into 8 ohms, doubling its output into 4 ohms and delivering 1200W when bridged. It operates in Class A for first 5 watts, after that it switches into AB, thus - unlike my Accuphase A-70 - the Moon Evolution 870A was not forcing me to switch on air-conditioning as it was barely lukewarm during its operation.

The 870A is a fully dual-mono design based on 16 bipolar transistors, 2x1.3kVA toroids, 300 000 µF of filtration capacity, negligible THD figures and a heroic damping factor. The amplifier (alike other Simaudio amps) is designed with no global feedback to achieve ‘real time amplification’.

The main power switch is at the rear panel, if you want to use the single-ended inputs you need to use supplied jumpers for XLR inputs pins. The 870A provides two pairs of speaker terminals to make bi-wiring easier.

Despite the unit looks quite ordinary on the pictures it makes an unforgettable impression in reality. Its case is finished in thick black anodized aluminum, with horizontally running heatsinks, perfectly damped milled top plate that features a large silver plate with the engraved Moon logo, and natural brushed aluminum curved extrusions on sides of the front panel. All black or silver versions are available too.
In Simaudio they do not mount any standard feet to their components – there are four conical steel ‘spikes’ instead in each corner of the bottom plate. All Evolution series devices can be stacked via replacing the spikes by damping aluminum/polymer bridges; that way you can save money for a dedicated rack and will have a very stylish high-end console.

Bass management


The Evolution 870A provides an ultra-high damping factor (>3500 for most of the range and >800 at 20kHz) that puts the amplifier into Soulution’s league. I expected supergrip on woofers and was not disappointed. The 870A’s bass performance was the best I ever heard in my room. Not only was the bass taut and weighty, it was also precise, richly textured and punchy like a machine gun. On top of that it remained super-controlled at any listening volume, no matter if the amplifier drove my TAD Evolution One speakers of Legacy Audio Aeris. The opening three-note motif on English horns that is followed up by fierce staccato in Rachmaninov´s Symphonic Dances were presented with punishing precision and deep articulation, stroke by stroke.

Clarity & delicacy


If the 870A was transparent and dynamic when powered up, it grew to be even more transparent and dynamic after a week of continuous playing. I was out of my house for few days so I am not describing the ‘getting use to the sound effect’, rather a real transformation that was noticeable right away. Is it a bad thing that the performance of a power amplifier is so dependent on thermal and electrical stabilization of its parts? I do not know but the truth is that Simaudio knows why they recommend not to power off their amps.

Tonal accuracy

Temporal resolution

Both the Moon Evolution 740P and the Moon Evolution 870A are effortless in midrange with natural timbres and top notch timing that brings the sense of immediacy to whatever I listened to. On top of that they are very musical devices, the 740P being a bit tonally truer than the 870A.

Tonal forwardness made the rock recordings explosive and lifelike, the jazz numbers intensively communicating, and the classical music a bit too much in your face. For example, the timbral richness of the 870A was not as vivid as that of my resident Accuphase A-70, and I could also sense a bit of edge in upper midrange, around 2-3kHz, which opened up the sound for more spark, but also made lesser recordings sound less digestible. The A-70 was beautifully pure in midrange and on the top, but it sounded darker, less articulated and softer in the bass than the 870A. Depending on your speakers balance you may prefer one or another.

Spatial resolution

Soundstage width
Soundstage depth

The soundstage was amazing - realistic, with tangible body, three-dimensional realism and lifelike locked-in-space images. Vocalists were not presented as disembodied or hovering voices, quite opposite they became very physical and palpable.

The soundstage of the 740P was as deep and wide as it was recorded on the source material. The preamp fantastically recreated the space around individual musicians, the recorded ambience was reproduced with magical presence and thus reshaping my listening room into a studio. It was clear which side of a microphone the artist was facing, if he (or she) was seated or standing, I could follow the fingers travelling along the neck of the guitar. Of the two, the 740P imaged more accurately, with pinpoint clarity. The soundstage of the 870A was comfortably deep but a bit narrower than I am used to. Thus it gave a spotlight focus on soloists and band frontmen, but also slightly emphasizing middle-front sections of a symphony orchestra.

Price as reviewed:519 000,- Kč

Recommended resellers

Platan Audio, Hlohovec / Bratislava, tel. +421 905 409 802

Associated components

  • Sources: Accuphase DP-720 SACD player, Accuphase DG-58 processor
  • Amplifiers: Simaudio Moon Evolution 870A, Accuphase A-70, TAD M2500, Jeff Rowland Model 201 monoblocks
  • Loudspeakers: Legacy Audio Aeris, TAD Evolution E1
  • Interconnects and speaker cables: AudioQuest Wild Blue Yonder, AudioQuest Redwood, Stealth Audio PGS-16, Stealth Audio Metacarbon, AudioQuest Vodka
  • Power conditioning: Nordost Thor (modified), Nordost Valhalla, Block Audio Snakeblock



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