Simaudio Moon Evolution 880M monoblock power amplifier Page 2

Matters of Control & Precision
JA will describe the 880M's performance in technical terms, but I suspect that it will measure pretty flat "from DC to light." I've always been aware of the small humps and bumps in the VTL's and Levinson's frequency response, and believed I was accounting for them in comparisons with other equipment. Having heard the 880M, I have to admit that I've been listening around these irregularities and accepting them as a kind of pseudoreality. Maintaining the consistency of, say, an acoustic piano's sound, or a singer as she varies her pitch and volume, was another area where the 880M sounded different from most other amps I've heard. Gauged against the bar raised by the 880M, other amps—certainly my older but still excellent ones—sounded a little like patchwork, their performance a smooth but subtle composite of slightly different instruments.

From an amp with the 880M's power output and ultra-high damping factor I expect iron-fisted control of a speaker's bottom end and effortless, lightning-fast transients. The Simaudios didn't disappoint. They reproduced low-frequency information with a precision and an effortless nonchalance that belied—or perhaps paid testament to—their superb control of the Sophias' woofers. Certainly the 880M's bottom end was taut and powerful, and notes began and ended crisply, with no timbral or temporal smearing. But it never sounded or felt fast per se. Notes and lines just flowed, without any artifacts or discontinuities that drew attention to themselves. In the Solti recording of Beethoven's 9th, the double basses had the sort of body and choral nature that a group of individual instruments has in a live performance. They didn't sound sharply drawn or imbued with finely etched detail, but instead had the relaxed ease that I hear in the concert hall. They were detailed and precisely located in space, but in a seamless, natural way; they didn't pop out of the background in the hyped-up, over-etched way that's often mistaken for "detail."

One of my favorite recordings for listening to a system's low-frequency reproduction is "Love Her Madly," from the Doors' L.A. Woman (LP, Elektra EKS-75011). With very good but not quite sublime components, or even those with deep, powerful bottom ends, the bass in this track will sound good, but will lack the bounce and subtle inner detail that a bass should have. I've heard other amps that give this bass line more raw power and impact than did the 880M, but none that bettered how well it reproduced its unique natural bounce.


The 880M was also superb at reproducing dynamic transients large and small. Again, it didn't sound fast, or as if its transients were unusually emphasized, but simply handled anything I threw at it with beguiling effortlessness. Friday Night in San Francisco, a live recording by John McLaughlin, Paco de Luc°a, and Al Di Meola (half-speed-mastered LP, Columbia HC 47152), absolutely explodes with dynamic transients, and my favorite cut is the first, "Mediterranean Sundance/R°o Ancho." The 880Ms sailed through this test, beautifully reproducing the live feel and crackling excitement of audience and guitarists alike. The tiny microdynamic shadings among the faint echoes of notes decaying into the background were reproduced with clarity. At the other end of the scale, the near-instant snaps from pppp to ffff had lifelike speed and power, with no sense whatsoever that the 880Ms were working hard.

That feeling of effortless precision extended up and through the midrange. Voices had a natural feel and timbre, a great example being the quirky, a cappella "Tom's Diner," from Suzanne Vega's classic Solitude Standing (LP, A&M SP-5136). Through the Moons, Vega's voice pressurized the air in my room exactly as a live person's voice does. It also had a three-dimensional realism—a sense that there was an actual body behind it, as opposed to a disembodied, two-dimensional voice flattened against the plane described by the speakers' front baffles. I've heard other amps produce a detailed, sharply bounded, even three-dimensional image of Vega's voice, but only the very best have matched the way the 880Ms translated the electronic signal into such a lifelike, coherent whole.

Comparisons from the Past
The Moon Evolution 880Ms deserve comparison with the very best amps I've heard in my system. VTL's S-400 Reference tubed stereo amp ($20,000 in 2005, reviewed in the December 2005 issue) stood out in my memory, particularly in terms of its ability to portray voices and instruments throughout the midrange. As good as the 880Ms were, and as dimensional and solid as their spatial portrayals of images were, they didn't quite have the refinement, and perhaps not as vivid a tonal palette, as I remembered the big VTL having. The 880Ms were certainly refined and tonally rich in their own right, or compared to the vast majority of top-tier amplifiers out there, but perhaps just a little less so than the S-400. The 880Ms, on the other hand, struck me as being a slightly more balanced overall. Both the VTL and the Simaudios had that effortlessness of sound heard when an amp's capabilities far exceed the demands placed on it.

Another reference point I harked back to while evaluating the 880Ms was my experience with the Halcro dm88 ($39,990/pair in 2006). It's been a while since I've heard the Halcro, but when I reviewed it for the August 2006 issue, it was the best amp I'd heard in my system. In addition to the effortless ease that I found so beguiling in the Moon Evolution 880M, the Halcro had a clarity that was unique among electronic components of any sort. Memories of pleasant experiences have a way of improving with age, so it's likely that I'm now remembering the Halcro a bit too fondly, but I don't think the 880M quite matched it in this sense. It was elusive and hard to put a finger on, but at times I thought I heard just the faintest background texture in the Simaudio's sound. On the other hand, the 880M outperformed the Halcro in at the low end, and in terms of power and precision of dynamic transients. These are all slight differences—I'm splitting hairs among the very best amps I've ever heard.

A Matter of Preamps
It wasn't at all surprising to discover that the best preamp I used with the Moon Evolution 880Ms was the Moon Evolution 850P (review in the works), or that they sounded best when run in balanced mode. The 850P is already so highly regarded for its transparency that I've been warned more than once to "be prepared to go completely through your system, top to bottom," and that "you'll be revamping and rearranging your listening room before you know it." With that sort of sonic microscope, I expected to find more nits to pick with the 880M: accentuations of any minor sonic thumbprints I might hear. On the contrary—combining the 850P with the 880Ms seemed to ameliorate any quibbles I'd had with the latters' sound and, if anything, accentuate its strengths. I've not yet tried to concentrate on the 850P or listen to it with other amplifiers, but pairing these two Moon Evolution models makes me look forward to the experience.

And that leaves us . . .
I found it hard to describe what the Simaudio Moon Evolution 880M was adding to my system's sound. Instead, I ended up identifying and describing what other components were adding that the 880M was not—a telling comment on the Moon's performance. Also telling is that the most relevant benchmarks I found for the 880M were the VTL S-400 Reference and the Halcro dm88, two of the very best amps I've heard, and each of which set new a standard for performance. The Moon Evolution 880M now joins that group.

As with any component that sets a new standard of performance, it will be difficult to fully identify the 880M's characteristics until another, better component comes along. The 880M wasn't completely transparent, nor was it the best amp I've heard in every aspect of sound—but its overall balance and consistency of performance are causing me to reconsider the sound of the other excellent amps I've heard.

I did most of my listening with the Moon Evolution combo of 880Ms and 850P preamp—an undeniably synergistic pairing. I also did enough mixing and matching to tell me that the Moon Evolution 880M's performance should be outstanding regardless of what other components it's hooked up to. It's one of the small number of superamps that are in as close orbit around planet Perfection as today's technology permits. The 880M is an excellent design superbly executed, with a professionalism and attention to detail that promise consistently outstanding performance and long, trouble-free life. $42,000 is a lot of money, but competitively priced in the context of the top echelon of high-end amplifiers.

Back in 2001, the Moon Rock was Simaudio's admirable first attempt at a state-of-the-art amplifier, and especially admirable given how short a time it took to design and produce. With the Moon Evolution 880M there are no such caveats—and none needed. It's the big-time, big-money, big-power, big-everything amp that the Moon Evolution line has lacked, and a fully fledged state-of-the-art amplifier. Highly and very enthusiastically recommended.

Newton Road
Boucherville, Quebec, J4B 5H2
(450) 449-2212

xsipower's picture

Well after years of being on the sidelines I decided to voice my concerns for the high end industry. Since my teenaged years I have loved the listening to good music through good equipment. I became an Electrical and Mechanical engineer, which was due in part to my love for building my own DIY equipment at home.

After reading Stereophile’s review of the Simaudio’s Moon Evolution 800M, I just couldn’t stand on the sidelines and not voice a concern about specmanship in the highend audio industry. I thought the large differences in published specifications vs. actual measurements was relegated to consumer electronics and not to five and even six figure (hopefully) state of the art audio equipment. The Evolution 880 clearly does not achieve some of the most important specifications that amplifiers are measured to.

Here below I distilled my concerns and finding:

Spec’d Output Power 8 ohms: 800W in 8ohms   

Measured Output Power 8 ohms: 800W in 8 ohms

Meet Spec.: Yes


Spec’d Output Power 4 ohms: 1600W in 4 ohms

Measured Output Power 8 ohms: 1050W in 4 ohms (fuse blown)*

Meets Spec.: No (<1.5x discrepancy)


Spec’d Output Current: 42A continuous

Calculated Output Current: Fuse blew into 4 ohms @ 1050W which is 16Arms

Meets Spec.: No (<2.6 discrepancy)


Spec’d Output Impedance: 0.004 Ohms

Measured Output Impedance: 0.125 – 0.132

Meets Spec.: No (<30X discrepancy)


Spec’d Frequency Response: 10 – 200Khz (0, -3db)

Measured Frequency Response:  90khz -3db

Meets Spec.: No (<2X discrepancy)


Spec’d Slew Rate: 70V/us

Actual Calculated Slew Rate: 20.5V/s

Meets Spec.: No (<3.4X discrepancy)


*With a 10A “long fast blow” fuse maximum input power is 1200W max.



The output power specification for this amplifier is continuous for only an 8 ohm load. The 4 ohm specification of 1600W is clearly momentary, or “peak” as the 10A fuse limits the output power to 1050W.

The argument that using a continuous sine wave to test amplifiers is not fair to the amplifier is incorrect. Wattage is Wattage, whether it’s from a music source or a function generator. A music source is said to have dynamics and therefore not tax the amplifier as a continuous sine wave does. This is true, but to do away with the ambiguity of testing amplifiers, the Industry uses the term as “rated continuous output power”.  If an amplifier is rated to output 800W most manufactures that follow IEC specification would specify it for continuous output power. This should be done with a sine wave a 1khz, but even if it’s done with a music source, the average power must equal a continuous 800W. Of course to output 800W of continuous RMS music power would require clipping the signal or having the music highly compressed. Power is Power. Can the Evolution output 1600W of continuous music power into 4 ohms? No.


The other very alarming measurement of the Evolution 800M is that a 1/3 power into 8 ohms the heat sinks reach dangerous temperatures. Other that than the high end amplifier industry, most manufactures limited exposed surface temperatures to 50C or less.  The high end industry seems to be fine with much higher temperatures. The Evolution 800M has surface temperatures of 73.5C. The SAFETY standard UL/ IEC 60950-1 for electronics allows for metal surfaces to reach 70C.

As with all of Simaudio's amplifier, the heat sinks are mounted with the fins in a horizontal plane rather than the traditional vertical plane. I assume they chose this for looks rather than cooling efficiency, since this arrangement is a very poor utilization of natural convection cooling. The purpose of using a heat sink with vertically mounted fins is to take advantage of the rising natural convection air moving over as large of a surface area as possible, with little or no obstruction in its motion.


I wish Stereophile would include in their review language that clearly states that the product does not meet its specification in the final summary of the measurements section of the articles. Instead in this article a poor excuse is given for it not being able to drive low impedance loads, but the review said that’s OK because music is not a sign wave. For heaven sake, this is a $42,000 amplifier and should perform as specified as do many "afordable" Best Buy purchased equipment.

I am very happy that Sterophile does actually test the equipment they listen to. Most other reviewers do not. It is a great service to all of us. The whole purpose of the review is to provide both objective and subject information to the reader so that they may know what they will be getting when they purchase the item.

I understand that the subjective portion of the review can have no objective scales, but when objective measurements are made they are very much tied to real physical scales set forth by various international agencies. My only other concern is that I have found in the last few sentences of the measurement section, a subjective assessment made of the objective measurements that not only seems to trouble others ( as I have read in posts on but myself as well. There have been recent reviews of amplifiers that for their astronomical price have very poor measurements.  At the end of the review a subject remark is made like “This is an amplifier that is as well-engineered as it is beautiful to look at.” That may be the reviewer’s opinion, but as an Electrical Engineer of 20 years’ experience and who closely follows both DIY and professional audio design, I had a very different opinion and hold the standards for saying “This is an amplifier that is as well-engineered “for such high priced equipment to a higher level. I would never have said what the review said for that product.

I am trying to be constructive with my comments and mean no disrespect to any of the reviewers.

John Atkinson's picture

To address a couple of the points you make:

1) My measurements of output impedance include the series resistance of 6 feet of approximately 14-gauge speaker cable.

2) Yes, the fuse blew under sustained drive into 4 ohms. But it is entirely possible that with a pulsed signal with a low duty cycle, the fuse would remain intact up to the clipping point. Note, BTW, that I don't hold the wall voltage constant for these tests, feeling that this is more representative of actual use.

John Atkinson

Editor, Stereophile

Robby's picture

1) 14 AWG cable has a resistance of 2.52 mOhm/foot

6 x 2.52 = 15.12 mOhms or 0.0152 Ohms which still makes the output impedance figure look bad compared to the spec.

2) Most energy will come from low-frequency musical elements and those are everything but low duty pulses. Most of them will be closer to sine waves and they will suck a lot of power when driven into speaker loads so there is still a risk to blow the fuse on bass-heavy music played loud.

JohnnyR's picture

Please be consistant at removing posts or don't bother removing any. Thanks

Just because some people can't face facts doesn't mean they are correct.

Robby is correct about the output impedance and the wire used to measure it, he is also correct that low frequency content tends to be sine wave not impulses.

This amp FAILS at a number of tests and should have been criticsed for doing so NOT praised.

We now return you to the usual excuses thanks for your patience.

John Atkinson's picture
JohnnyR wrote:
Please be consistent at removing posts or don't bother removing any. Thanks

You have been warned multiple times, Johnny R, that posts of yours that in our opinion are nothing more than abuse or trolls will be deleted without notice. You don't want your posts deleted, please refrain from personal attacks and stick to addressing the points being made by others.

JohnnyR wrote:
This amp FAILS at a number of tests and should have been criticised for doing so NOT praised.

Please think about where you learned about this amplifier's apparent shortfalls in its measured performance.

John Atkinson
Editor, Stereophile

anjeza1987's picture

I agree with your comments xsipower.Additionaly,the high temperatures,will shorten the life of the equipment.And this one is very beautiful.

And greatly appreciated the measurments carried out from Mr Atkinson.

Regards from Greece.

GeorgeHolland's picture

just change the specs to be a bit below where actual problems arose then jack up the price even more and they would have a "winner"  wink I understand it could double as heater during the cold months. This brings about the possibility of owning another amp that doesn't get hot for the summer months. A win-win for the high end dealers that wish to double their

freddiek40's picture

Hmmmm.  800 watts, 1 year warranty = $42,000


Or you could buy 2 sets of Bryston 28B.  1000 watts, 20 year warranty, $36,000 (remember this is for 4 of the 28Bs).


I think the Sims are clear losers.

John Atkinson's picture

freddiek40 wrote:
Hmmmm.  800 watts, 1 year warranty = $42,000

From the company's website: "The Standard Warranty is 1 year parts and labour.

"Upon receipt of a validated Product Registration (via our website or by regular mail), the warranty can be extended up to an additional 9 years.

"To receive this free-of-charge extended warranty (up to 10 years), the product must have been purchased new, from a MOON Authorized Dealer. and registered with us within 30 days of your invoice date."

John Atkinson

Editor, Stereophile

MVBC's picture

And that includes the cooling fins...

xsipower's picture

Hello Freddiek40,

If you read Stereophile's review of the Bryston 28B-SSTyou will find that it was another very “hot” amplifier.

From Stereophile review:

“I preconditioned the Bryston 28B-SST by running it at 330W into 8 ohms for an hour. ….. The amplifier's heatsinks were way too hot to touch after 60 minutes, but despite the thermal abuse, the amplifier didn't turn itself off.”

What is way too hot to touch? This can be quite subjective, but is usually considered starting between 65-70C. That is when contact for more than a brief few seconds leads to a burn. The Bryston 28B-SST temperature was clearly above this threshold based on Stereophile’s test.

I would not consider the Bryston 28B-SST to be designed thermally any better than the Evolution 800M. That being said, the Bryston 28B-SST functioned through the entire tests without failure.

I agree that with higher temperature two things must be considered by a buyer. First is the placement of the equipment where it will get enough ventilation as well as not being touched when driven hard.  The second consideration is that the MTBF (Mean Time before Failure) increases with higher operating temperature. Temperatures of 70C are not destructive to most electronic components since most are rated much higher. The component that is most affected by high temperatures are electrolytic capacitors the bulk of which are the main power supply filter/storage capacitors. The life time of these are impacted quite drastically as temperatures go up.

 You would defiantly want a robust warranty on a “hot” running amplifier.

I appreciate the difficulty that designers of amplifiers face. There are many unknowns to the designer. The most unknown is the load. Some speakers are easy to drive, some are very difficult. Speakers are complex loads and can drop their impedance to half or less of their rated impedance at certain frequencies. Not only that, but during these low excursions the current and voltage can be way out of phase and that puts the highest stress on the amplifier’s output transistors.

 I believe that over the many decades that this industry has been around; the adoption of standardized testing methods and specifications has helped to alleviate the ambiguity of how a particular amplifier can perform.  Tests like the 1/3 power test into load, the specification of continuous RMS power into 8,4 or 2 ohms loads, etc., give the buyer the tools with which to marry a speaker with an amplifier. Of course the tests do not reflect “real life” music listening, but they are not meant to. They are meant to give assurance that they can at least play music continuously at a rated power in to a rated load.

Do we listen to music at continuous RMS value of let say 800W. Most likely not. But then, what music are you listening to. Is it highly compressed? Does it have a lot of low frequency component which where most of energy goes in recreating music. What speaker are you driving?

ON…and On….

John Atkinson's picture

xsipower wrote:
What is way too hot to touch? This can be quite subjective, but is usually considered starting between 65-70C. That is when contact for more than a brief few seconds leads to a burn. The Bryston 28B-SST temperature was clearly above this threshold based on Stereophile’s test.

The Bryston was reviewed before I bought an infra-red thermometer. But I was taught at university that "too hot to touch" or more accurately, to keep your hand on" was equivalent to >60C.

And the one hour at 1/3 power test is very much a worst case for amplifiers with a class-B or -AB output stage like the Bryston and Simaudio.

John Atkinson

Editor, Stereophile

xsipower's picture

Thank you Mr. Atkinson for the elaboration on "too hot to touch". Yes I agree that 1/3 power is very rigorous on the amplfier with a class-B or AB output.

xsipower's picture

Sorry. I need to make a correction in my above post. I wrote "MTBF increase with temperature". That I wanted to write was MTBF decrease with increase in temperature.

tmsorosk's picture

Yeah the Brystons are clear winners until you hear both offerings , then there is one clear winner ( Simaudio ). Warranty and watts are one thing but for the true audiophile your ears must decide .

JohnnyR's picture

Sorry but , "I think this amp sounds better" with no objective testing is guess work and just opinion. Amps need to meet their specs otherwise the manufacturer is making a faulty product. If they can't meet their own specs then how can you trust it to last or perform at it's best?

GeorgeHolland's picture

My oh my with such an under engineered amp, they are going to see plenty of repairs that is if anyone buys it to begin with.