Vinylphile Magazine : Equipment Reviews

Simaudio • Moon 310LP Phono Stage

By Rich Teer | March 17th, 2011

Canadian audio manufacturer, Simaudio, hardly needs an introduction as they’ve been part of the high-end audio scene for more than three decades. They offer numerous products in two ranges (the cost-no-object Moon Evolution Series, and the more affordable Moon Series), including integrated amplifiers, pre- and power amplifiers, DACs, transports, and phono stages. All of Simaudio’s products are designed and manufactured in-house.

There are two phono stages in Simaudio’s current product line up: the Moon 310LP, and its little sibling, the Moon 110LP. An optional external power supply, designated the Moon 320S, can be used with the 310LP. The 320S is an option that the user may either purchase at the same time as the 310LP, or at a later date. I think this is a good idea in principle, because it allows users to upgrade more easily as funds allow.

I requested a sample of the 310LP and the 320S and evaluated the 310LP both with and without the 320S.

Technical Description

The Moon 310LP is a relatively compact solid state phono stage. Replacing the previous generation’s Moon LP5.3, the 310LP has one pair of single-end inputs, a pair of single-ended outputs, and a pair of balanced outputs. It has user-selectable gain, input resistance loading, and input capacitance loading. Unusually for a phono stage in this price range, the 310LP also has user-selectable equalisation curves: both RIAA and IEC are available (above 20 Hz the curves are the same, but the IEC curve specifies a subsonic filter below that frequency).

The rear panel contains the signal input and output sockets (all of which are gold plated), a gold plated grounding post, an IEC mains socket, and a four-pin XLR socket to which the umbilical cord from the optional external power supply is attached. By fitting an IEC socket (rather than using a captive cable), Simaudio gives 310LP owners the ability to use after market AC cables should they desire to do so. The 310LP is intended to be permanently powered, so there is no main power switch.

The front panel, which is made from a 9 mm thick sheet of machined aluminum, is available in either a silver or black anodised finish. It houses the blue LED power indicator.

Inside, there are two circuit boards: one for the phono stage electronics, and the other for the isolated power supply. The latter uses an ultra low noise toroidal transformer and boasts a reasonably generous 14,000 μF of capacitance. The phono stage circuitry uses high quality components in a dual-mono configuration, and features several sets of jumpers for each channel. It is these jumpers that enable the user to select the gain, the equalisation curve, the load capacitance, and the load resistance. A larger set of gold-plated jumpers are used to select between the internal power supply and the optional external one. The 320LP ships with the jumpers selecting the internal power supply, so they must be changed before connecting the 320S. One minor criticism I’d like to mention at this juncture is this: the jumpers used to select the gain etc. are not gold plated. I’d like to see this addressed because the jumpers are right in the very sensitive signal path, and gold plated jumpers would be less susceptible to corrosion. (Simaudio informs me that the jumpers are made from a highly conductive non-corrosive alloy, so my—admittedly small—reservations in this respect might be unfounded.)

The Moon 320S is the 320LP’s optional dedicated external power supply. It is housed in a chassis identical to the one used for the 310LP, except for the rear panel connections. The 320S’ rear panel contains an IEC mains socket, a four-pin XLR socket to which the umbilical cord connecting the 320S to its accompanying 310LP is attached, and the main power switch (even though Simaudio recommends leaving the 320S powered semi-permanently).

Inside the power supply’s case we find more high quality components, including a larger ultra low noise toroidal transformer, a pair of 200 mH chokes, and a total of more than 35,000 μF of capacitance.

Setup and Listening

As mentioned previously in the technical description, the Moon 310LP has user-adjustable settings for gain, load capacitance, and load resistance. After some experimentation, I decided to use the maximum gain (66 dB in my single-ended system), and values of 0 pF and 100 Ohms for the load capacitance and resistance respectively.

For best performance, Simaudio recommend leaving the 310LP powered up at all times (unless one is going away for an extended period). I followed this advice, so the 310LP was powered up for nearly the entire review period. After several dozen hours of informal listening, I started my formal evaluation: first with the Moon 310LP on its own, and then later with in conjunction with the Moon 320S power supply.

One of the first things I noticed about the 310LP was its very strong bass performance—so much so that I not entirely convinced that it doesn’t emphasise the lower bass just a touch. I’m not talking about the awful, overblown, one-note bass that afflicts those car boom boxes that plague many a suburban setting (why so many people with such equipment feel the need to inflict their questionable musical taste on the rest of us by playing it at ear-shatteringly loud volumes is beyond me). The effect I’m describing is much more subtle than that.

I also wouldn’t describe it as a gross colouration. In fact, the more I think about it, the less I think that I’m hearing a problem and the more convinced I am that what I hear is a testimony of the 310LP’s wide bandwidth design and (perhaps) the better cartridge loading 100 Ohms provides for the Lyra Parnassus. Two tracks which really illustrate what I’m talking about are Who Were You Talking To (from South African a cappella group Ladymith Black Mambazo’s 1987 album, Shaka Zulu [WEA 925 582-1]) and The Great Gate of Kiev from Mussorgsky’s Pictures at an Exhibition (specifically, the version on The Power of the Orchestra [Analogue Productions AAPC 2659-45]). In the former, the group members stomp their feet towards the end of the song. In addition to the initial stomp, the reverberation from the hall can be heard and felt. This effect is even more pronounced in the latter track, where a bass drum is periodically thwacked. Not only can the initial boom be heard and felt, but the sense of space and movement of air engendered by the hall’s acoustics is also very satisfyingly reproduced.

The Moon 310LP’s midrange reproduction also doesn’t disappoint. Although it is perhaps a touch on the dark side, male voices (like those from Ladysmith Black Mambazo) are well portrayed, and do not suffer from any chestiness. Female voices, for example, Dusty Springfield’s rendition of The Look of Love from the Casino Royale OST [Colgems COSO 5005-45], are also beautiful.

Another example of how well the 310LP fares with the mids and highs is the celeste from the second movement of Fritz Reiner’s reading of Prokofiev’s Lt. Kije [Classic Records/RCA Victor LSC-2150]. The sound the hammer makes as it strikes the metal plates is clearly discernible. With lesser phono stages, the initial hammer strike tend to be lost in the ensuing chime. As good as it is, the 310LP’s treble doesn’t have quite the sparkle and air of the very best phono stages, but I consider this to be a relatively minor shortcoming. The bells and piano from opening minutes of Mike Oldfield’s Tubular Bells [Virgin Records V2001] illustrate this quite well.

The 310LP handles dynamic contrasts very well. The finale of the first part of Tubular Bells gets very busy, but the 310LP manages to keep up just fine: there’s no congestion here. Even though a lot is going on, it is easy to follow the individual instruments.

When it comes to revealing little details buried in the mix, the 310LP does a very good, but not spectacular, job. Compared to the (admittedly much more expensive) reference level phono stage I had on hand, some grit and grain hides some fine details. The effect is pretty subtle, fortunately, so I don’t consider this to be a major fault.

Imaging was, on the whole, pretty good, but not a razor sharp as it could be. For example, the arch of the members of Ladysmith Black Mambazo was a little diffuse, making it a bit difficult to place the individual singers. The same applies to Tubular Bells’ Nasal Choir: although the members weren’t congealed into one big homogenous image (a good thing), their individual positions were hard to pin down exactly.

Related to imaging is the soundstage, which the 310LP supplies in abundance. The soundstage is wide and deep (although I have heard wider and deeper in my system), extending beyond the edges of my speakers.

The preceding description applies to the 310LP without the optional Moon 320S external power supply; adding the 320S catapults the 310LP’s already good performance onto an even higher level. When the 310LP is used with the 320S power supply, grain is reduced (enabling fine details to be more clearly heard), transients are better defined, and harmonic overtones are improved (for example, the glockenspiel in Tubular Bells). There is slightly more air around instruments, and image specificity is also improved somewhat. As one would expect, noise is reduced: what was a very quiet phono stage is rendered even quieter by the addition of the 320S.

Verdict

The Moon 310LP is a very good phono stage. With one or two relatively minor reservations, it has a strong audio performance and is well built. Fit and finish are very fine, and the ability to adjust the gain, load capacitance and resistance, and the equalisation curve is very welcome and makes for a very flexible phono stage. It would have been nice if the adjustable parameters could be changed without opening the case, but the additional front panel switches would have added substantially to the parts cost, so it is an understandable decision (especially when one considers how infrequently most users would want to fiddle with these adjustments).

As good as it is on its own, adding the Moon 320S power supply improves the performance quite substantially. The fact that the 320S can be added so easily by the end user means that the cost of the two units can be spread out over time, making them more accessible.

With good sound quality and adjustability that’s almost unheard of at this price point, I highly recommend a personal audition of the 310LP if you’re in the market for a new phono stage. The 320S is also highly recommended. The great thing is that because you can add the latter at a later date, if the choice is “cheaper cartridge plus the 310LP + 320S combo” or “more expensive cartridge plus just the 310LP”, I’d be more inclined to go the second route with the proviso that a 320S would be next on my shopping list. If you already have a great cartridge (and funds permit), then buying the 310LP and 320S together would make more sense.

Specifications

Description Solid state phono stage with optional external power supply.
Frequency response 20 Hz to 20,000 Hz ±0.5 dB.
Crosstalk -100 dB (1k Hz).
Gain 40, 54, 60, and 66 dB (single-ended outputs); 46, 60, 66, and 72 dB (balanced outputs).
Distortion < 0.001% THD (20 Hz to 20,000 Hz).
Input impedance 47, 100, 470, 1k, and 47k Ohms.
Input capacitance 0, 100, and 470 pF.
Output impedance 50 Ohms (single-ended), 100 Ohms (balanced).
Phono equalisation RIAA and IEC.
Maximum input voltage (@ 40 dB gain) 58 mV RMS.
Maximum input voltage (@ 54 dB gain) 11 mV RMS.
Maximum input voltage (@ 60 dB gain) 6 mV RMS.
Maximum input voltage (@ 66 dB gain) 3 mV RMS.
Signal to noise ratio (@ 40 dB gain) 110 dB, 114 dB with 320S.
Signal to noise ratio (@ 66 dB gain) 88 dB, 92 dB with 320S.
Dimensions (hwd) 80 mm x 190 mm x 285 mm.
Weight 3 kg (310LP), 3.5 kg (320S).
Finishes Natural and black anodised aluminum.
Serial number of units reviewed L579998 (310LP), L5510074 (320S).
Price $1,800 (310LP), $1,400 (320S).
Warranty Two years transferable (ten years with registration).

Manufacturer

Simaudio
1345 Newton Road
Boucherville, QC J4B 5H2
Canada
(450) 449-2212
www.simaudio.com

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