July 2004

Simaudio Moon W-6 Mono Amplifiers

by Marc Mickelson

Review Summary Sound "The bass region [has]…tremendous agility, depth and power," "space and natural reverberation…are revealed to an amazing degree," and "the dynamic agility and power reserves…are remarkable." "Their sound is matter-of-fact. They do not sound euphonic or colorful, preferring to pass along the signal fed to them without editorial addition." Features "Fully balanced mono amplifier that reportedly outputs a whopping 425W at 8 ohms and 650W at 4 ohms"; "Simaudio has championed its Advanced Renaissance technology, which eliminates feedback, and very short signal paths as the keys to its amplifier designs. I suspect the W-6es' use of 16 bipolar output devices and high damping factor (quoted as 800) are keys to the sonic signature of the amps." Use "I preferred balanced connection -- no surprise given that the W-6 is a fully balanced design. Although I couldn't perceive or quantify a reduction in noise from using the balanced inputs, the music sounded purer, which led me to believe that there was less noise." Value Not exactly "budget-priced components, but [the W-6es'] price is a fair distance from the stratosphere for similarly powerful amplifiers."

Lost in the hubbub surrounding SACD, DVD-A and multichannel audio are the ever-improving sound of CD playback and the renaissance of solid-state electronics. A decade ago, the division between the performance of tube and solid-state components was vast, with few audiophiles jumping from one camp to the other. I was among this throng; I experimented with solid state but settled down with tubes. While I don't regret my choice (if you can call it that), I have heard a number of contemporary solid-state amplifiers that have made me respect how other audiophiles live -- and even enjoy visiting their world from time to time.

One of these amps was Simaudio's Moon W-5, a stereo powerhouse that I reviewed back in early 2000. What's most surprising to me is that the W-5 remains in Simaudio's product lineup with no signs of being replaced. The Canadian company has released an upgraded Moon W-5 Limited Edition ($6000 USD), but the stock W-5 ($5250) is still available, which is testament to its combination of "power, authority and sonic splendor," as I stated in my early 2000 review.

With all of this in mind, I was very interested in hearing Simaudio's Moon W-6 mono amplifiers, which were released in early 2003. Knowing what I did about the W-5, I immediately thought about the W-6es, "Do people actually need more power than the W-5 can deliver?" In reality, the W-6 monoblocks are probably meant as much for home-theater use as for two-channel audio. They are more compact than the W-5, run very cool, and can deliver almost a kilowatt of power into 2-ohm loads -- enough power for the explosions in blockbuster movies. Even so, the W-5 never proved to be shy of power while I was using it, which makes the W-6es seem like overkill. Let's see.

Lunar exploration

The Moon W-6 is a fully balanced mono amplifier that reportedly outputs a whopping 425W at 8 ohms and 650W at 4 ohms (the first 10 watts are in class A; beyond that, output is in class AB). It's also a high-current design, with 68 amps of maximum peak current output. Krell, Mark Levinson and a host of other manufacturers produce similarly powerful balanced amps, but to my knowledge none of these costs what the W-6es do: $7000 per pair. This doesn't exactly make the W-6es budget-priced components, but their price is a fair distance from the stratosphere for similarly powerful amplifiers.

Simaudio has championed its Advanced Renaissance technology, which eliminates feedback, and very short signal paths as the keys to its amplifier designs. I suspect the W-6es' use of 16 bipolar output devices and high damping factor (quoted as 800) are keys to the sonic signature of the amps. The W-6 has the same unique oval chassis of all Simaudio amplifiers, which uses a structure of metal tubing to support the chassis and faceplate. All of this is said to minimize the sonic effects of external vibration. The W-6 measures 19"W x 7 1/2"H X 14"D and weighs 46 pounds. Each amp comes with built-in spikes that sink too deeply into carpet to allow proper ventilation, so if you eschew platforms, place the amps on tile or wood flooring only.

System

The W-6 monoblocks spent most of their time in my system driving Wilson Audio MAXX Series 2 speakers, although I also used the amps with Wilson Audio WATT/Puppy 7, ProAc Response D38, Energy Veritas V2.4i, and Paradigm Signature S8 speakers. Preamps were a Lamm L2 Reference or Atma-Sphere MP-1 Mk II; the voltage gain of the W-6es is high enough that using the amps with a tube preamp may cause some hiss that could be distracting. Digital sources were many: Esoteric DV-50 and UX-1 universal players, Esoteric X-01 SACD/CD player, and my reference Zanden Model 5000 Mk III DAC and Mark Levinson No.37 transport connected with an i2Digital X-60 BNC-terminated digital cable. Speaker cables and interconnects were Siltech Signature G6 Forbes Lake and Signature G6 Eskay Creek respectively, with Nordost Valhalla in use for a time as well. Power cords were Shunyata Research Anaconda Vx, Anaconda Alpha, and Taipan, as well as a pair of Siltech Signature G6 Ruby Creeks.

I connected the W-6es via both their single-ended and balanced inputs. I preferred balanced connection -- no surprise given that the W-6 is a fully balanced design. Although I couldn't perceive or quantify a reduction in noise from using the balanced inputs, the music sounded purer, which led me to believe that there was less noise. I greatly preferred the Siltech G6 Signature cables to those from Nordost with the W-6es, as the amps' inherent sound (more to come on that) was too lean with the Nordost cables.

Turning the amps on requires that you flip the rear-mounted switch and press a small bottom-mounted pushbutton, while turning the amps off requires that you only use the switch. The W-6es ran only slightly warm to the touch and consume a mere 40 watts at idle, so keeping the amps on at all times, as Simaudio recommends (and practically forces you to do with the two-step turn-on sequence), produced no worries unless storm clouds rolled in. The amps worked flawlessly, and because they were on 24/7, they were ready to play music whenever I was ready to listen.

I had two in-use issues with the W-6. First, the inputs and outputs are placed in a cluster very near each other. Connecting speaker cables and using the balanced input was difficult as the input is directly above the outputs. Second, I hated the speaker binding posts, which you can tighten only by hand. Also, the collar below the nut sometimes doesn't turn as you're tightening, making it easy to chew up spade connectors, which happened to me. Learn from my mistake -- be careful when tightening these binding posts.

Sound

As good a place as any to start discussing the W-6 monoblocks' sound is in regard to a comment I made in the last amplifier review I wrote, on the very different deHavilland Aries GM70, which had a hard time "controlling large woofers" like those in the MAXX Series 2. No such trouble with the W-6es, whose high damping factor helped the woofers start and stop in binary fashion -- without slop, overhang or mushiness. The bass had stentorian power, especially with the MAXX 2s, which go much lower and with greater dynamics than any speaker I've heard in my system. I've been listening to a lot of Ani DiFranco lately, and as I mentioned in another recent review, Evolve [Righteous Babe RBR030-D] is fast becoming one of my favorites. On "Here for Now," the W-6es portray the bass region with tremendous agility, depth and power. "Authority and detail," say my notes. But the upright bass and kickdrum on "I Love the Life I Live" from Buddy Guy's wonderful Blues Singer [Silvertone 01241-41843-2] shows that the W-6es' low-end prowess isn't just a matter of aural thrills. Here, the delineation of drum and bass is better than it has ever been; the "whomp" and "purr" are easily untangled. It's no surprise that solid-state amps can excel at bass reproduction, but the Simaudio W-6 excels even among amps that portray the bass region particularly well.

Blues Singer also brings to light another strength of the Simaudio W-6 monoblocks: the way the amps dig into a recording and render its innermost nuances. On Blues Singer, the space and natural reverberation on every cut are revealed to an amazing degree, but this does not happen at the expense of overall balance. As I observed of the W-5 years ago, the sound of W-6es is rife with smoothness and finesse, not edginess and grain that can give the impression of detail and space until the music gets loud or the listener tires. Perhaps it's easiest to say that the W-6 monoblocks are truly SACD ready. Accordingly, I listened to a host of the Bob Dylan remasters. The Freewheeling Bob Dylan [Columbia CH 90321] sounded intimate and seductive; John Wesley Harding [Columbia CH 90320] sounded rough and metallic, as it always has; and Dylan's storytelling and metaphoric flourishes on Blood on the Tracks [Columbia CH 90323] were more intelligible, and therefore understandable, than I've ever heard them. None of these recordings is a sonic blockbuster, yet through the high-power Simaudio W-6 monoblocks, all were a treat to hear. These SACDs are the editions that scholars will be using to study Dylan, I am convinced, because they offer the greatest insight into his music.

The dynamic agility and power reserves of the W-6 monoblocks are remarkable. These amps can play at low levels without obscuring minute detail -- such is their resolving power -- and then hit thunderous crescendos seemingly with power to spare. For fun one afternoon, I played various kinds of music to hear what level the combination of the W-6es and MAXX 2s could reach before turning hard or compressing dynamically. I never reached the point at which the combination turned ugly -- it played PA-system loud and as clean as it did at moderate levels. With symphonic works such as Beethoven's Symphony No.7 on JVC XRCD [Victor JMCXR-0006], crescendos reached live volume levels, the amps and speakers able to go from soft to very loud -- over 100dB -- with realistic speed. Such performance is thrilling but not the sort of listening that we regularly do at home. However, it was reassuring to know that when power was needed, the W-6es delivered with aplomb.

Solid-state amps that are rumored to sound like tubes often do so by sounding darker and more full than the competition. This is not the case with the Simaudio W-6es, which do not add weight or bloom. Their sound is matter-of-fact. They do not sound euphonic or colorful, preferring to pass along the signal fed to them without editorial addition. This does not mean, on the other hand, that they are gritty, grainy or impose an electronic or hi-fi pallor on the music. Their treble is smooth while sounding very detailed and extended to the cosmos. Their overall character is leaner than that of some of the competition, but this doesn't translate to a detached coolness. Rather, the W-6es sound pure, not even a little rough and ragged. They impress not with obvious sweetness but rather with perceived high fidelity, including their ability to play very soft or very loud when the music calls for it.

As I listened, I thought over and over again that I would love to hear the W-6es connected to a pair of Magnepan MG3.6/R or MG20.1/R speakers. The amps would never run out of power, would control the large planar-magnetic bass panels of these speakers, and, I suspect, mate well with Magnepan's true ribbon tweeter. I love tubes, but if I owned Magnepans (and there are many good reasons to do so), I would seek out a pair of W-6es with which to power them.

Strength vs. strength

I reviewed the Mark Levinson No.434 monoblocks last year, and while aural memory is imperfect, I do recall enough about those amps (and have my review to fall back on) to compare them and the W-6es. These amps are natural competitors due to their mono configuration and high power output. However, the No.434s cost $8800 per pair, almost $2000 more than the W-6es, and they are built differently, with internal fans for cooling and no external heatsinks. The W-6es look more like traditional high-end amplifiers, while the No.434s are more sleek and attractive. They also have a standby mode that the W-6es lack.

In terms of sonic performance, anyone who thinks that competently designed solid-state amps sound alike should hear these two. The differences are not night-and-day obvious, but they are striking enough to make you realize that all solid-state amps are not designed and manufactured in similar ways. The No.434s have a chunkier sound -- not tubey bloom and fullness but rather density and heft. Their bass goes just as deep as that of the W-6 monoblocks but has greater weight and, therefore, impact. The treble of the No.434s doesn't have the perceived extension of that of the W-6es, and it sounds a bit blunt and clunky in comparison. Both amps sound fundamentally transparent through the midrange, but the Mark Levinson amps sound a bit gray as well, as though there is a very fine layer of noise overlaying voices, something that's easier to discern in comparison to the W-6es, which are a clearer window on the music. The W-6es sound more focused and lean, the No.434s more weighty, dense and darker.

I enjoyed the Mark Levinson monoblocks, especially driving Revel Ultima Studio speakers. The sound of the amps mated well with the speakers' great clarity, lending the presentation a sense of balance. I'm not sure that balance would be present with the Simaudio amps driving the Revel speakers, but it was there with the W-6es driving either the ProAc D38s or Paradigm S8s, which responded particularly well to the W-6es' power and sonic character.

Overall, given my tastes and the music I listen to most, I enjoy the Lamm Industries hybrid amps I've heard more than the Simaudio W-6es, but the Lamm M1.2 Reference, for instance, is almost three times the W-6's price and one-quarter its power. Simaudio's W-6 monoblocks are what I would buy if I were seeking lots solid-state watts.

Conclusion

"Do people actually need more power than the W-5 can deliver?" Probably not for most listening unless they have large rooms and insensitive speakers. But while audiophiles may not need the power of the Simaudio Moon W-6 monoblocks, they may want it for its effect on the sonic presentation, and I wouldn't argue. The seemingly limitless power of these amps certainly contributes to their sound, especially in terms of playing at very high SPLs. However, no other amp I've heard can go from soft to loud with equal agility, widening the dynamic range of an audio system to a distinguishable degree.

I can't say for sure that the W-6 monoblocks just flat out sound better than the W-5, let alone the W-5 Limited Edition, but I can say that they are exceptional in some specific ways, including in the areas of bass control and depth, portrayal of space and overall lack of coloration. They are tremendously powerful amps that will almost certainly drive any speaker extant, although I would love to test this theory with a pair of Magnepans. The things we reviewers are willing to do in the name of research!

...Marc Mickelson
marc@soundstage.com

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