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Equipment Review

May 1999

SimAudio Moon I-5 Integrated Amplifier

by Doug Schneider


Review at a Glance
Sound Vivid, fast, tight and controlled; has the "ability to unravel the nuances of complex musical passages;" exceedingly neutral sound, particulary through the midrange, especially compared to tube electronics.
Features High-quality parts and gorgeous looks; ample inputs, including one specifically for a surround processor; remote control.
Use Its 70Wpc can drive a wide array of speakers, even tough loads; direct surround-sound input (A4) is not specifically labeled, so do not use it for a line-level component.
Value Who needs separates with a well-built and -engineered integrated amp like the Moon I-5 around?

Bigger is better -- the more the merrier. Like many audiophiles, I have followed this train of thought. As a result, I have separates to the max. What's more, some of them are really big components. I have a separate D/A converter and transport instead of a single-box CD player, a preamplifier with separate power supply, a separate phono stage, and even mono amplifiers. While it may seem ridiculous to some, there is some very sound reasoning behind separates when one is pursuing the ultimate in performance: more ability to mix and match.

However, while some audiophiles may think that separates are the rule, truth be told, you can still attain simply fabulous performance and save a bundle of money, not to mention the increased convenience, by purchasing integrated components that still offer plenty of performance and value. Remember, there's another saying that goes "it's not the size of the ship, it's the motion of the [sound] waves" -- or something like that. In some cases the integrated amplifier, one that combines preamplifier and power-amp functionality in one package, makes perfect sense. The best of these are pieces that are expertly designed to give the best sonic performance with the convenience of a single-box unit. Enter the SimAudio I-5, an integrated amp that offers true high-end performance via the refined circuitry of the company's much more expensive separates, but in a convenient, elegant and user-friendly package. The price? $2595 -- capped off with an impressive ten-year warranty.


The I-5 belongs to SimAudio's Moon series of components that also includes power amplifiers (the W-3 and W-5) as well as preamplifiers (the P-3 and P-5). In addition, there is a new CD player called the Eclipse. SimAudio has other product lines like Celeste, but it is the Moon series that is built to the company's highest standards. They include things like complete refinement of their circuit designs, military-grade printed circuit boards, a plethora of the best electrical components available, and a chassis that includes a stunning and thick front panel. Summed up, it's gorgeous.

There are some that may balk at a price well over $2000 for just 70Wpc of power, particularly from an integrated amplifier and especially when it's easy to find more power for less money. In fact, SimAudio offers higher-powered integrated amplifiers in its Celeste line that cost much less. But as keen-eared audiophiles know, total power is not everything. In the high-end world, ultimate sonic refinement is a costly exercise.

The I-5 is a class-A/B design that can deliver 70Wpc into 8 ohms and 110Wpc into 4 ohms. It uses SimAudio's Advanced Renaissance Technology, which refers to their implementation of designing without the use of negative feedback in the circuit. According to SimAudio, Moon-series amplifiers are able to handle short-term loads down to 1 ohm (the March 1999 issue of Stereophile shows the 175Wpc Moon W-5 to deliver a whopping 1480 watts into a 1-ohm load!). While the I-5 would not be described as a powerhouse like the separates, it can at least be described as a powerhut. It's a feisty fighter that can drive most reasonable speakers with ease. I used it with speakers ranging from a lowish 84dB to moderate 88dB efficiencies and found no problems whatsoever.

The chassis is a slick design that employs SimAudio's well-known rounded heat sinks on the side. This little feature provides heat-sink functionality while making the amplifier look smaller and more refined in appearance. The front is brushed aluminum, 3/8" thick. To my eyes, its gray color with a hint of purple is one of the most attractive on the market. A nice touch is the integrated Tiptoe-like feet that add visual elegance in addition to practicality by giving the I-5 a rock-solid footing. The I-5 exudes refinement, with diminutive size and elegant styling that will fit into any décor. Overall quality and attention to detail are first-rate.

The front panel has a minimal number of controls and an LED display panel. The volume control is actually a free-spinning wheel attached to a digital optical encoder. There are 51 possible volume levels shown on the digital display panel, from 0 to 50. The left and right channels are shown independently which allows for balance adjustments (which can only be changed on the remote control). Low-level listening requires more precise adjustment in gain, so positions 1 through 35 make smaller increments in volume level compared to positions 36 through 50. I found most of my listening was done from about 35 to 40, although this will depend on the loudspeakers used.

On the back are two sets of WBT binding posts for left and right speakers, six sets of single-ended inputs and a tape loop -- enough for complex systems. The chassis itself measures only a foot and half wide and a few inches in height, so there is not much room to maneuver with wires. Despite the small size, I found that there is ample space to get all connections on, even oversized audiophile spades and RCA connectors. The CD input is, obviously, for your CD player or DAC. A1, A2, A3 and A5 are standard line-level inputs for devices that output 1 to 4 volts; tuners, cassette decks, you name it -- this is where they go. A4 is a little different. It is designed to be used with a home-theater processor and is actually routed straight through to the amplifier. The explanation is in the manual, but I believe that SimAudio should either cover this plug or mark it explicitly on the back panel because you should never plug a line-level device like a CD player into this input. With a home-theater processor, this input allows you to transfer gain control over to that device. A nice feature, but take care in its use.


Overall, I am quite taken by the simplicity and effectiveness in the I-5's design. While many may think that volume adjustment and input switching require little thought to implement, think again. There is more to it than meets the eye, and it can make all the difference between whether a product is pleasurable to use or not.

Input selection, whether done using the remote or by switch on the front panel, is fast with no ticks or pops heard through the speakers. When an input is selected, its abbreviation is displayed for a few seconds (e.g., CD) before the display reverts back to show only the volume level. Muting is immediate, and volume adjustments occur at just the right rate. For those who prefer to listen in complete darkness, or if you feel that the illumination of the front panel can decrease the sonic performance of the unit, the display can be completely turned off. I can see the benefit of turning the display off from a "red lights staring at you" point of view, but I detected no sonic benefit in doing so. The only thing I did find absent on the I-5 that I wish it had is a headphone jack, which I feel would add some convenience.

The I-5 has two levels of being powered on. Like many other high-end components, there is a main power switch on the back that, once you have the I-5 set up in your system, gets left on. This keeps at least part of the circuitry in a warmed-up state for optimal performance. A secondary power switch on the front is the one that gets engaged and disengaged for daily listening.

The remote control supplied is a multi-function unit that controls all functionality of the I-5 as well as the company's other devices like their CD player. One thing about the remote control is that compared to most other remotes, this one is made of metal, is fairly long, and even has extruded aluminum along its side that matches the I-5’s look itself. In the end it is HEAVY, and I'm sure you could hit a homer with it. When I mentioned that to SimAudio, they responded that "you'll have a hard time breaking it!" Gotta give them that.

System and listening

I used the I-5 in two systems and with a fair number of loudspeaker combinations, including with speakers from Cliffhanger Audio, Merlin, NSM Audio, Shamrock Audio and Von Schweikert Research. Compatibility was fine with all. Nirvana Audio S-L speaker cable and interconnects were my wire of choice, and as for source, it was either my Theta digital components or a Kenwood DVD player. Depending on the system in which it was used, all components were plugged into either a Blue Circle Power Line Pillow or a Power Wedge power conditioner.

What became apparent from the first listen and reconfirmed to the end was that the I-5 has a character that I sum up as vivid. Subjectively, this integrated amp is very fast-sounding, meaning that from the bass through the high frequencies music shines with pristine clarity, tightness and control. There is no extra bloom, hang or fullness where there shouldn't be. These qualities are likely the reason this amplifier swings effortlessly through any musical style and made it an easy match for a wide variety of really good speakers. The entire frequency range has excellent detail and it has a marvelous ability to unravel the nuances of complex musical passages. Recordings that mix multiple voices, choral works for example, or large-scale classical pieces with a large number of instruments are rendered with excellent separation and distinction between each performer. Even so-so sounding classical recordings, such as Ennio Morricone's beautiful soundtrack for the movie The Mission [EMD/Virgin VRGN-0086001], become much easier to dissect. In short, low-level resolution, while not necessarily the very best you can buy, is very good and can be considered outstanding at the price.

Surprisingly, the I-5 reminds me of Sonic Frontiers Power 1. A tube amp? Is this to say that the I-5 is tooby? It's not necessarily solid-statey either. In my review of the Power 1, I described it as an amplifier that does not sound like tubes at all. In fact, that amplifier, despite being only 55Wpc, has a neutrality that I feel many would identify as closer to that of solid state! If listeners didn't know the technology, they would likely not be able to identify it blind. Tubes, solid-state -- I've found that it really doesn't matter if the music sounds natural, and that's the sound of the I-5 and Power 1. More importantly, I found that both of these amplifiers, despite having only moderate output ratings, perform well against much higher-priced units when used within their limits. In other words, while they cost a couple thousand bucks each, they are performing like units costing many thousands of dollars. They're just not as powerful.

What's surprising is that the I-5 does all this without sounding bright, sharp or strident -- assuming, of course, that your other components are not bright, sharp or strident. If they are, you may find yourself in trouble because the I-5’s neutrality and resolution make it very revealing. In fact, it sounds so clean and neutral that it does bring up one caveat: it comes across as a tad dry, perhaps even a little cold, particularly through the midrange and into the higher frequencies. Electronics that would not normally be called lush may sound that way in comparison to the I-5. Those who favor a warmer sound, or one with more presence in the midrange (maybe to mask other deficiencies in their systems) may not warm up to the I-5's sound. I don't fault the I-5 in this regard; instead, after long listening, I found this neutrality to be perhaps a step closer to the sonic truth.

Take Jewel's Spirit [Atlantic CD 82950], for example. On this recording, Jewel’s voice is placed up-front and center -- it’s the "focal point" of the music, albeit in a somewhat sterile recording. Same goes for Jim Cuddy's voice on All in Time [WEA CD 23107]. It's a favorite of mine, a recording in the same vein as Spirit, but not with quite the dynamic agility. The vocals through the I-5 are presented with stark presence with sharp contrasts to the instrumentation and backing vocalists behind. "Clean and vividly detailed" my listening notes read. So vivid, in fact, that you're drawn right in, despite the flaws of the recording. I've heard these recordings on other systems that compensate by rolling off the extremes or caramelizing the midrange. In turn, you may get a more palpable sound, but it won't be one as real. Holly Cole's Temptation [Alert Z2-81026] never sounded better than through the I-5. It has a bit too much warmth that, when played on speakers or electronics that impart their own sense of warmth, overwhelm the listener. The I-5 neither adds nor subtracts, and in cases like this, it is a relief. To me, this is exactly what good electronics should do -- simply let what is there through. The more I listened to the I-5, the more I sensed a rightness to its sound.

Just for kicks, I added in the $449 JPS Labs Power AC cord to see if I could up the ante a bit. In fact, it did make the I-5’s sound a bit better. The character of the amp was unchanged, but there was a little more blackness to the background, and transients were a smidgen sharper. I tried Nirvana and Blue Circle cords too, with similar results. After-market power cords are not a necessary addition, and in this case made only a slight difference, but they are one upgrade worth considering if you want to take your equipment a step closer to all-out performance.


First up was a comparison to my reference Blue Circle BC-2 mono amplifiers and BC-3 linestage preamplifier that proved most interesting. The BC-2s are pure class-A, singled-ended, tube/solid-state hybrids that deliver 75 watts each. The BC-3 preamplifier is an all-tube unit. The total price for the set nears $10,000. Despite the significantly different technology (and widely varying price), the BC-2s and SimAudio Moon I-5 are roughly the same power rating (at least at 8 ohms; the I-5 is more powerful into lower impedances). The Blue Circle combination has subjectively more bass weight and fullness -- rounder if you will, but not fat. The I-5, however, sounds tighter and quicker on things like percussion. The upper bass to lower midrange has a little more warmth through the Blue Circle combination, but both the Blue Circle and SimAudio gear showed exquisite detail. Midrange frequencies are a little more incisive through the I-5, with a sharper, more immediate presentation that I would describe as stark. On the other hand, the Blue Circle gear has a tad more fullness that some will describe as warmth and bloom. The Blue Circle gear presents male vocals, for example, more up-front to the listener and with more body, where the I-5 is a little more laid-back -- reticent in comparison. Cymbals, bells and the such have a fuller, more fleshed-out sound through the Blue Circle equipment, but the I-5 shines with impressive immediacy and speed. Both amps are extended in the high frequencies without ever being bright or edgy. When it comes to imaging, the I-5 casts rock-solid, well-defined images amidst a soundstage that has very good width and depth. The Blue Circle gear, also an imaging champ, does not cut out the images quite as specifically, but has more apparent depth and a tad more resolution of space. Taken as a whole, I preferred my Blue Circle gear, but the I-5 proved that it plays in the big leagues.

SimAudio's Celeste 4150se made a stop at my house after John Stafford reviewed it. Priced about the same as the I-5, it is twice as powerful and, of course, you need a preamplifier. It reminded me of a very good amplifier I owned years back, the discontinued Classé Audio model Fifteen (also from the Montreal area of Quebec). Both the Celeste 4150se and the Fifteen can deliver power in spades, but have finesse and a warmth to their sound. Speakers that need the juice come to life with either. My past experience with the 4150se says that it does not sound as quick and lean as the I-5 and is a touch less refined. The 4150se is more powerful in the bass region for sure and has far greater power output, but in comparison, I believe it to be a smidgen less transparent and neutral. I sense that the difference between the Celeste and Moon series is a step toward ultimate neutrality and transparency -- removing the last pane of glass.


Functionally, aesthetically and sonically, the folks at SimAudio have spun out a winner with the Moon I-5. It's a product with broad appeal. In fact, the only type of person this integrated amplifier may not appeal to are those who think that they must pay exorbitant amounts of money to get the best equipment. More expensive gear does not always sound better. In fact, I believe that SimAudio may harm themselves a little by pricing their products just a little too reasonably. While $2595 is not chump-change, I could easily see the I-5 selling for up to $4000 and still be considered good value (just like I would imagine the W-5 priced closer to $7000 instead of less than $5000 like it is). Don't think this is an endorsement to jack the price up -- it’s not. It's just to note that the value of the I-5 is abundant.

Beautifully styled in a compact package with ease-of-use in spades, the I-5 is a high-quality integrated amplifier that will appeal to anyone looking for a taste of the best. Well-designed ergonomics and a full-function remote control do nothing but add convenience, and a single-box design eliminates a lot of hassle. Sonically, the I-5 is top-class with little to criticize and a lot to praise. The I-5 is a high-quality integrated amplifier that can be used with moderately priced speakers right up to reference level. I wouldn't mate it with cheap speakers because a product of this caliber would likely be overkill. And I would not match it with something that presents a killer load or has super-high power demands because, well, while 70Wpc is sufficient for most listeners, it won't be in all cases. However, with appropriate speakers from, say, $1,000 right up to $10,000, perhaps even more, this integrated amplifier is an exceedingly neutral performer worthy of the best components you can match it with.

...Doug Schneider

SimAudio Moon I-5 Integrated Amplifier
Price: $2595 USD.
Warranty: Ten years parts and labor.

3275, 1st Street, Unit 1
St. Hubert, Quebec Canada J3Y 8Y6
Phone: (450) 445-0032
Fax: (450) 445-6626

E-mail: info@simaudio.com
Website: www.simaudio.com

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