June 1, 2009

Simaudio Moon i3.3 Integrated Amplifier

An integrated amplifier is an attractive option for those of us without the money or space to assemble a high-quality audio system of multiple boxes, each serving a different function. Although some audiophiles believe that combining several components in a single box invariably leads to compromises in sound quality, that doesn’t have to be the case. I’ve reviewed several integrated amplifiers that rival separates, and around which I could easily build a musically satisfying, wonderful-sounding system.

By my count, the Simaudio Moon i3.3 is the tenth integrated amplifier I’ve written about for the SoundStage! Network. Retailing for $3300 USD in its base configuration, it’s not inexpensive; buy the i3.3 complete with its options of onboard digital-to-analog converter ($400), phono stage ($300), and balanced input ($200), and the price is $4000, saving $200 over buying these options separately.


If you’ve visited SoundStage! V, you may already have seen the i3.3, which was introduced at the 2009 Consumer Electronics Show. The i3.3 fits between the i-1 and the i5.3 in Simaudio’s Moon series of integrated amplifiers, but the ability to add the options of DAC, phono stage, and balanced input puts it in a class of its own in Sim’s product line. It’s the most flexible high-end audio component I’ve ever reviewed.

Despite the i3.3’s incredible functionality, Sim has managed to fit all of its functions into a handsome, compact case measuring just 16.88"W x 3.5"H x 14.75"D. Its unobtrusive appearance belies the sort of muscle of which this little powerhouse is capable: despite its modest size, the i3.3 is rock solid, and you need only pick it up to appreciate as much. Its metalwork is nicely finished, and the brushed-aluminum faceplate looks attractive, strongly suggesting impressive craftsmanship and quality within.

Under the top plate is a massive power supply that includes an oversized 400VA toroidal transformer. Simaudio rates the i3.3’s output at 100Wpc into 8 ohms, this doubling to 200Wpc into 4 ohms, with class-A output for the first 5W, and continuous current delivery of 12 amps and peaks of 22 amps. I was curious to hear how these numbers would play out when I actually listened to music, but with a power supply this robust, the i3.3 looked set to deliver on Sim’s promise that it would have little problem providing enough power for all but the most demanding loudspeakers.

On the rear panel are the power switch and the receptacle for a detachable IEC power cord. A single pair of high-quality, gold-plated binding posts can accept spades, banana plugs, or bare wires. There are also a slew of connections, including four line-level single-ended inputs. If you buy the DAC and balanced-input options, you can connect up to ten components to the i3.3. The DAC itself accepts four inputs: one TosLink, two S/PDIF, and one type-B USB connection. The fully balanced input uses a circuit intended for use with a source that outputs a fully balanced differential signal via an XLR connector.

Additionally, there are two non-amplified outputs on the back, labeled FIX (fixed) and VAR (variable). FIX can be used for recording devices such as tape decks or a CD recorder, while VAR enables connection to an outboard power amplifier, should you desire to use only the i3.3’s preamplifier section. Below the digital inputs are two of Simaudio’s proprietary SimLink connectors. If the i3.3 is used with other Simaudio Moon products, SimLink enables communication between the components via supplied cables. For example, if SimLink is used to connect the CD3.3 CD player to the i3.3, pressing Play on the CD3.3 will automatically signal the i3.3 to switch to the CD input. There’s also an infrared (IR) input, a 12V trigger output for powering up a component connected with a 12V trigger input, and a full-function RS-232 port for custom installations.

The layout of the front panel is very clean, with Simaudio’s characteristic oversized display, which can be read from across the street. (Pressing the Display button turns it off.) The display identifies the selected input and sampling frequency (if the digital input is used). There’s also a Standby button for disengaging the input section while leaving the audio circuitry powered up. Adjacent to the front-mounted 1/8" mini-jack, for connecting an iPod or other portable audio device, is a 1/4" TRS headphone jack for private listening. A Mute switch silences the signal to the loudspeaker terminals, the headphone jack, and the fixed and variable line-output connectors, while the Spk Off button disengages only the signal to the loudspeaker terminals -- useful when listening through headphones. A large rotary dial controls the volume, while two input-selection buttons allow the user to easily scroll through the impressive number of source components with which the i3.3 can be used.

The i3.3’s appearance is unobtrusive enough to easily integrate with almost any room or décor, and it is ridiculously well endowed with features and power -- functionally, I was unable to find fault with it. My only complaint is about its full-function remote control. Given the high quality and extraordinary attention Sim has paid to every detail -- even the owner’s manual is just about the most useful and informative I’ve ever read -- the remote seems second-rate. Lightweight and plastic, it resembles something that might be included with a $100 DVD player, in sharp contrast to the full-metal remotes shipped with the Moon i5.3 integrated amplifier and CD5.3 CD player, which I reviewed two years ago. However, the i3.3’s remote did perform flawlessly; with it, I was able to adjust the volume in fine increments unavailable with lesser volume controls.

See our Simaudio Moon i.3.3 photo gallery.

System and sound

The i3.3 found its way into a system that included PSB Platinum M2 bookshelf speakers, to which it was connected using AudioQuest Type 4 speaker cables terminated in banana plugs. Source components included an NAD C542 CD player linked to the i3.3 with Kimber Kable Tonik interconnects. The NAD’s coaxial digital output sent the digital datastream to the i3.3’s DAC via an AMX Optimum AVC-31 coaxial cable. Analog duties were performed by a Thorens TD-160HD turntable fitted with a modified Rega RB-250 tonearm, on which was mounted a Dynavector DV-10x5 high-output moving-coil cartridge. The turntable was also connected to the i3.3 using AMX Optimum RCA interconnects.

I let the Simaudio play for quite a few hours before picking up my pen to jot down any notes. In the manual, Simaudio claims that the i3.3’s sound will continue to improve during its first 400 hours of use. I don’t think it took nearly that long for the i3.3 to be fully broken in, but I’ll leave it to others to decide that for themselves. What I did notice was that the i3.3 reminded me a lot of the i5.3. Obviously, such a statement must be approached with caution -- I haven’t heard the i5.3 in two years -- but when I compared the listening notes I took for that review with what I was hearing from the i3.3, there was more than a little similarity between the two integrateds.

First, the i3.3’s wonderfully clean-sounding reproduction of the high frequencies was very clear and open. If your taste tends toward a more transparent sound, the i3.3 won’t disappoint you. Its reproduction of Emma Kirkby’s voice as it soared into its upper register on "Columba aspexit," from A Feather on the Breath of God: Sequences and Hymns by Abbess Hildegard of Bingen (CD, Hyperion CDA66039), was completely effortless. When I turned up the volume so that the music filled the room, the sopranos of Gothic Voices accompanying Kirkby sounded clear, well separated, and natural. In fact, unless a recording itself was bright, I never found the i3.3 harsh or grating. This is not to say that it sounded laid-back or lush -- it just managed a nice balance between sounding detailed but not analytical, full but not fat.

DAC, Phono Stage, and Balanced Input Options

As mentioned in the "Description" section, there are options of adding to the Simaudio Moon i3.3 an onboard DAC ($400), a phono stage ($300), and/or balanced input ($200). If all three are selected when the i3.3 is bought new, the fully loaded i3.3 costs $4000, a savings of $200 over later adding them separately. Although the review sample was fitted with all three options, I never used the balanced inputs because I don’t own a source component with balanced outputs. I did, however, spend some time evaluating the DAC and the phono stage.

The DAC uses a Burr-Brown PCM1793 chip that accepts 16-24-bit data with sampling rates of from 44.1 to 192kHz. The digital datastream can be fed to the DAC via the i3.3’s USB, TosLink, or S/PDIF inputs. Using the S/PDIF input and bypassing my NAD C542 CD player’s own DAC, I spent some time listening to Elliott Smith’s posthumously released New Moon (CD, Kill Rock Stars KRS455). On "Going Nowhere," Smith’s vocals sounded leaner and more detailed through the Simaudio’s DAC than through the NAD’s, which made them sound fuller, a touch more forward, and less distinct. Like the i3.3 itself, its DAC sounded very clear and open, making it easier to appreciate such small details as the sound of Smith’s fingers against the strings of his acoustic guitar, and the strings’ resonance as they excited the wooden body of the instrument.

Of the two DACs, I preferred the i3.3’s for its even tonal balance, which did very little to highlight any part of the music. Nothing sounded too forward or recessed unless those qualities were parts of the recording itself. This went a long way toward my being able to hear differences among the many CDs I played through it. The NAD was able to produce warmer, more fleshed-out bass, though it wasn’t able to match the i3.3’s ability to delineate those low frequencies and tease them apart. At $400, I think the i3.3’s onboard DAC option is an excellent value that offers an affordable upgrade path if you have an aging CD player or DVD player with digital output whose sonic performance is lacking.

The optional phono stage includes three settings that can be adjusted for use with moving-magnet or moving-coil cartridges. The phono stage is set at the factory for compatibility with a moving-magnet, so I didn’t need to make any adjustments. If you use a moving-coil, your dealer can remove the i3.3’s top plate and adjust the phono stage’s resistance loading, capacitance loading, and gain. The manual explains it all very clearly, and includes a full-page diagram of the phono card to make it easy to make these adjustments.

Listening to vinyl through the i3.3 was a real treat. The channel separation was superb, as were detail retrieval and clarity. On "I Used to Love H.E.R.," from Common’s Resurrection (Relativity 88561-1208-1), the phono stage did a superb job of handling the bass. The beat on this track was solid, my bookshelf speakers filled the room, and the vocals were clear. Stage depth was very natural, and music flowed with ease and composure. It would have been fun to listen to this track through larger, floorstanding speakers capable of deeper bass than my PSB M2s, but with the i3.3’s firm grip on the low end, I never felt I was missing too much. And the sound of "See You Later," also from Elliott Smith’s New Moon, was absolutely glorious. Smith’s acoustic guitar was warm and full, his voice sweet and detailed. The lowest notes sounded firm and weighty, with an enveloping bloom that commanded my attention.

If you’re thinking of getting into vinyl, or want to upgrade from an inexpensive phono stage, the one aboard the Simaudio Moon i3.3 is a good place to start. Buy it, set it up, and just enjoy it. You can then spend the money you’ll save by not buying a more expensive (though not necessarily a better-sounding) phono stage on more LPs.

. . . Philip Beaudette

The excellent clarity and detail made it easy to hear differences between recordings, and within the same recording. On Neil Young’s Sugar Mountain: Live at Canterbury House 1968 (CD, Reprise 2-516758), the tape hiss in the opening track, "On the Way Home," was impossible to ignore, though Young’s voice still came through pure and sweet. The tape hiss was still audible in "Mr. Soul," though now much lower in level, which brought Young’s guitar and voice to the front of the stage and gave this track a somewhat different flavor. My point here is that the i3.3 wasn’t contributing anything to the sound. Rather, it allowed music to emerge without editorializing on it, without changing any of the colors of the aural painting. Of course, this can be good or bad, depending on the quality of the recording and of the rest of the system. If you plan on using the MP3 input, I suggest making sure the music you play has been imported at the highest quality possible.

Another of the i3.3’s strengths was its reproduction of space. It was very good at communicating a sense of scale and space, expanding the apparent soundstage beyond the boundaries of the room. For example, in Radiohead’s "Faust Arp," from In Rainbows (CD, Red/ATO 0001), Thom Yorke’s voice was front and center, between the speakers, while the violins emanated from above and behind his head, creating a sense of depth. This was easy to visualize, and made the front wall melt away and my room flood with music. And the i3.3 did a fine job of capturing the size of the church in which the Hildegard of Bingen disc had been recorded. Unlike In Rainbows, which was recorded in a studio, A Feather on the Breath of God conveys a real space; the i3.3’s reproduction of that space was highly convincing.

Clarity aside, another aspect of the i3.3’s sound that reminded me of the i5.3 was a vivacity and liveliness that brought a real sense of energy to music, seeming to propel it forward with vigor and intensity. On "Jigsaw Falling into Place," also from In Rainbows, Phil Selway’s drums were punchy and vibrant, full of body and drive, the i3.3 sounding a bit forward as it projected the music into the room. I always got the sense that the i3.3 had plenty of power in reserve; I imagine you’d need a big room, or a very challenging speaker load, before you drove it into clipping. I never even got close.

The i3.3’s bass reproduction was absolutely superb: tight and fast, starting and stopping on a dime, keeping firm control over the PSB Platinum M2s’ mid-woofers. Not only did the i3.3 produce bass with good impact and punch, it did so with great clarity -- I could easily hear details glossed over by some other integrateds. There was no added weight or warmth, but there was great impact and punch. One thing the i3.3 didn’t do was add a sense of bloom, or fatten up the low end to make the music seem fuller than it was. It presented a drier sound that more easily allowed me to hear the character of the low frequencies, and to appreciate subtleties such as the way they decayed.

Overall, the i3.3 was thoroughly enjoyable to listen to. As I enjoyed recordings of everything from Sonic Youth to Rachmaninoff, there was always a sense of rightness that never failed, regardless of the music I played.


I compared the Simaudio Moon i3.3 with Bryston’s B100 SST integrated amplifier ($3900), which, like the Simaudio, can also be fitted with an onboard DAC and phono stage. Although both integrated amplifiers combine multiple functions in a single box, there are a few notable differences between them. For starters, the i3.3 uses a single, massive toroidal transformer in its power supply, while the B100 is fully dual-mono. Both amplifiers are rated to output 100Wpc into 8 ohms, although the Simaudio’s rating of 200Wpc into 4 ohms exceeds the Bryston’s 180Wpc into that load.

With regard to features, the i3.3 is the better equipped. Neither its balanced input nor its USB DAC input can be found on the B100, although the Bryston does provide one more TosLink input than the Simaudio. The B100’s phono stage works only with moving-magnet or high-output moving-coil cartridges, whereas the i3.3 can also be used with low-output moving-coils. A full-function remote control is included with the i3.3, but is a $400 option for the B100. Both integrateds are hand-built in Canada; Bryston provides a 20-year warranty, while Sim offers a still very impressive 10 years. Finally, without DAC or phono stage, the B100 costs $3900, $600 more than the base-model i3.3 without those options.

There were some definite sonic similarities between the two integrateds. Both sounded extremely powerful and offered well-defined images across broad, deep soundstages. Each leaned toward a dry sound, with no added weight or bloom in the bass. Each portrayed low frequencies with exceptional control and definition, although I found the Simaudio had a touch more speed and punch in the bottom end. Overall, the i3.3 presented music with a bit more energy; its pace, rhythm, and timing were more involving and lively than those of any other integrated amplifier I’ve ever heard.

The i3.3 and B100 were both very clean sounding, but the Bryston was more transparent -- an impressive feat, given the transparency of the Simaudio. Although both integrateds sounded very open and detailed, the B100 let me see into the music even more easily. With "Your Rocky Spine," from Great Lake Swimmers’ Ongiara (CD, Nettwerk 30691 2), both amps created a large stage across which the musicians were clearly outlined, but with the B100 I almost felt as if I could get up from my listening chair and walk between them. At the highest frequencies, both the Simaudio and Bryston were extended and controlled, neither sounding bright or hard, but rather smooth and effortless.

At this level of quality, it’s impossible to pick a clear winner -- each integrated had its own strengths. Personal preference will dictate which is right for you, but I can’t imagine making a mistake with either. In the end, some of the Simaudio’s extra features (balanced input, USB DAC input, compliance with low-output moving-coil cartridges) could be what tips the scale in that direction. Obviously, your choice will depend on your requirements.


Simaudio has made very little compromise in sound quality in achieving the Moon i3.3’s level of flexibility. Not only is it the best-equipped integrated amplifier I’ve come across, it’s also one of the best sounding. The price isn’t cheap, but buying a product such as this is a long-term investment, and the i3.3 is backed by a decade-long warranty. When you consider all of the options you can add, and the cost of assembling a system of separates of comparable quality that would perform all the same functions, the i3.3 is reasonably priced. You could easily spend a lot more and not get nearly as much.

If you value a revealing, engaging sound that will get your toe tapping and your head nodding, you owe it to yourself to audition the Simaudio Moon i3.3. It’s a little bit special, and one of the most enjoyable integrated amplifiers I’ve had the pleasure of reviewing.

. . . Philip Beaudette

Price of equipment reviewed