Simaudio Moon 310LP phono preamplifier

There’s a problem when you start getting into high fidelity sound. You begin at a point which you think is reasonably modest in terms of cost (but which most people outside of the high fidelity community would consider somewhat over the top). And pretty soon start to feel the need to go even further.

When I returned to listening to vinyl after a considerable break, I initially used a NAD PP 2 phono pre-amp that I’d bought in Singapore at some point in the early 2000s. But then I went on a hard search for a true audiophile phono preamplifier at a fairly reasonable price and came up with the Moon 110LP V2 (currently priced at $900). I should note, this was long before I started working here.) I used that with a range of turntables for a while and it was perfectly pleasing. But then, as so often happens, I decided that I should explore what more I could extract from my collection of vinyl.

So I upgraded the phono preamplifier, followed by the turntable, followed by the phono cartridge. Next thing I knew I was running a turntable source system priced at more than ten thousand dollars. The phono preamplifier element of that system was still a product from Moon by Simaudio. It’s the next step up, the Moon 310LP phono preamplifier. (Don’t worry, you can go even further on this journey. Pushing forwards, you can consider the Moon 610LP at $15,000, or even the Moon 810LP at $24,500.) But it’s the Moon 310LP that I’m living with, and looking at here.

A note of caution: remember, I bought this unit for my own use. I imagine that there are scientific studies showing that this kind of predisposes me to a psychological phenomenon in which I want to hear things which justify the expense. Against that, I’m very aware of this. Extremely aware.

Simaudio Moon 310LP phono preamplifier

In short

  • The Simaudio Moon 310LP is a balanced-output phono preamplifier supporting both moving magnet and moving coil level cartridges
  • Gain levels of 40, 54, 60 and 66dB (single-ended) and 46, 60, 66 and 72dB (balanced) selectable
  • Input impedance of 47 ohms, 100 ohms, 470 ohms, 1 kiloohms and 47 kiloohms, selectable
  • Input capacitance of 0, 100 and 470pF, selectable
  • RIAA and IEC EQ curves, selectable
  • 1 x single-ended stereo input (2 x RCA)
  • 1 x single-ended stereo output (2 x RCA), 1 x balanced stereo output (2 x XLR)
  • Signal to noise ratio: 110dBr @ 40dB gain, 88dBr @ 66dB gain
  • Frequency response: 20-20,000 hertz ±0.5dB
  • Crosstalk: -100dB @ 1000 hertz
  • THD (20-20,000 hertz): 0.001%
  • IMD: 0.009%
  • Input overload: 58mV RMS @ 1kHz @ 40dB gain setting; 3.0mV RMS @ 1kHz @ 66dB gain setting
  • Dimensions: 178mm wide by 76mm tall by 280mm deep
  • Weight: 3.1kg
  • Price: $3700
  • Available at fine high fidelity retail outlets, and direct from distributor's retail division (Simaudio Moon 310LP phono preamplifier)

More about the Simaudio Moon 310LP

As you can see from the above section, the input loading section of the Moon 310LP is extremely versatile. You have four levels of gain, adjustable input impedance and even a choice of two EQ curves. The IEC curve is identical the RIAA curve except that it has a gentle infrasonic filter.

The balanced outputs are useful for reducing noise that might be picked up in the connections between the 310LP and the preamplifier it is feeding. I used these outputs for my listening.

There is no power switch. Moon envisages it being left on all the time, but you can just switch off at the power point if you’re going away for a while.

One somewhat backwards step from a user experience point of view in the upgrade from the 110LP to the 310LP is the method by which you change the input settings: gain, impedance, capacitance and EQ curve. On the 110LP these are controlled by DIP switches on the underside of the unit. On the 310LP you have to remove the lid and move jumpers on one of the circuit boards.

Simaudio Moon 310LP phono preamplifier interior

Don’t get me wrong, the procedure is straightforward and the instructions in the manual are clear. No, the only problem I had was getting the lid off the unit. It’s secured with four Phillips-head screws on each side which are easy enough to get out. But the casing, three planes of moderately thick-gauge steel, gripped the chassis rather tightly and simply didn’t want to move. Don’t worry if this happens to you. Just slip the tip of a flat screwdriver in between the case and the chassis in a couple of places – it’ll be pretty obvious where – and gently lever the case up. It takes but a moment. I did this a few times because of the cartridge switching – and doing this was trivially easy compared to the cartridge changes themselves – but most people will either never need to open it up to change the defaults, because they’ll be using a regular moving magnet cartridge, or do it only once to cater for a moving coil cartridge.

One of the nice things about this level of input flexibility is that you can try a range of settings with your cartridge to see whether one setting or another produces the best results. But a word of warning: don’t plug it in with the lid off to facilitate this process. There are spots on the power supply board which are 230 volts live.

You may notice a 4-pin socket on the back of the unit, labelled “DC Power”. For a while Simaudio sold an external power supply, the Moon 320S, as a performance upgrade. This was discontinued some years ago. This DC power input is not compatible with the Moon 820S optional external power supply available for some very high-end Moon devices, such as the 610LP and 810LP.

Listening with the Moon 310LP phono preamplifier

I used the Moon 310LP with the following equipment

Simaudio Moon 310LP phono preamplifier

I held off from doing this review for quite a while because while I’d used the Moon 310LP with several cartridges, all of them were moving magnet or moving iron kinds with a regular output level: approximately 5mV for a 5cm/s groove modulation. For which there are many, many phono preamplifiers, including the majority built into amplifiers and preamplifiers.  But in this review I wanted to go somewhere I’ve never been before: moving coil. Well, actually, for the 80s and 90s I did use a moving coil cartridge, but it was a high output Adcom model that produced around 2.5mV for that 5cm/s modulation. So where I really wanted to go was to low output, which is really why you choose moving coil. You see, the main criticism of moving magnet cartridges is that the weight of the magnet, sitting on the far end of the cantilever from the stylus, reduces the stylus’ responsiveness to groove modulations. Inertia, you see. Moving coil cartridges reduce this weight, and thus the inertia, by using coils on the cartridge and fixing the magnet to the cartridge body. A few loops of copper wire weighs considerably less than a lump of magnetised metal.

And that’s the norm for moving coil cartridges. A few loops. For a high output cartridge, you need a lot more loops, which pushes the weight on the far end of the cantilever up, closer and closer to the weight of a magnet. So, really to get the full benefit of moving coil cartridge technology, you need a regular low output model.

(Which makes me wonder: why aren’t there any low output moving magnet cartridges on the market? You could perhaps get the same results – without the complications of attaching electrical connections to a moving coil – by having lots of fixed coils surrounding a much smaller, lower-mass magnet on the end of the cantilever. I’m pretty sure that such things as neodymium magnets, characterised by a very strong magnetic field for their mass, didn’t exist back in the olden days in which I came into high fidelity. But what about now?)

So, moving on from that aside, I have never had a system with a truly low-output cartridge. And I confess I was a little worried. The Goldring Ethos MC cartridge is rated at 0.5mV for 5cm/s groove modulation. A 0.5mV to 5.0mV ratio is in decibel terms 20dB. That’s the additional boost required of a phono preamplifier compared to the typical real (ie. not my hypothetical) moving magnet cartridge. What would that mean in terms of noise? If any extraneous noise were picked up between turntable and phono preamplifier, it would be a lot louder. Would I hear it? Would my enjoyment of music be diminished by an audible noise floor?

No. No. Not at all. Not in the slightest. I was a bit amazed. I’d somehow managed to convince myself that the enormous additional boost must have some impact. But it didn’t.

Simaudio Moon 310LP phono preamplifier

With the Thorens TD-1600 turntable and the Goldring Ethos providing the signal, in terms of noise level I might as well have been listening to a CD (well, except from surface noise from LPs, but not much can be done about that.)

Whew! Throughout a lot of listening, there wasn’t the slightest hint of noise that I felt able to attribute to the additional gain. Indeed, I suspected that if there were such a thing as a perfect LP – no groove noise whatsoever – there’d have been no noise at all. It would have been, ahem, “digital black”. Of course, though, I could hear all the groove noise with utter clarity.

And with some actual records?

So, I span a lot of vinyl. Simaudio recommends a run-in period for the Moon 310LP. I’m not so sure such things are necessary for electronics, but I am convinced they are for electro-mechanical devices, such as phono cartridges. So after a fair bit of use with the other cartridges, I installed the Goldring Ethos and played, uncritically, nearly forty LP sides before starting to write up this review.

Simaudio Moon 310LP phono preamplifier

I started with King Crimson’s Starless and Bible Black from 1974. My pressing is a Japanese one I bought back in the day. None of this modern 180-gram stuff, just a pristine pressing with about a clean a surface as I’ve ever heard on any LP. I’m not going to attempt to disentangle the relative contributions of the cartridge and Moon 310LP. But just as it had worked with the other cartridges, the musical delivery was flawless. The powerful bass lines were captured from the vinyl and delivered with authority and clarity, even through the most frenetic sections of playing in “Lament”. Then on to “We’ll Let You Know”, in which the piece is built up from fragments, with Fripp’s weird guitar off to the right of the sound stage and chunks of percussion bouncing around the stage until final focus is achieved towards the end as Bill Bruford’s full drum kit kicks in. Instrument placement was perfect and stable and every little detail was present and accounted for. I found myself turning up the sound higher and higher, and even so the space around the instruments remained empty of unwanted noise.

There was unwanted noise on the next selection, Eumir Deodato’s rock/jazz fusion album, Deodato 2, his second US album release. But that was in the groove, not produced by my equipment. Someone had a low-level buzz in their amp, and of course this was faithfully delivered. The first track on this album is an astonishing cover of “Nights in White Satin”. I haven’t played this album for a while – I purchased it new in 1973 or 1974 for, I see from the price sticker, $6.99 – so I wasn’t expecting a whole lot. But despite the almost fifty years that have elapsed, the grooves are clean and undamaged, and the Moon 310LP was perfectly transparent in delivering all this to the amplifier. The powerful Latin groove was brought out beautifully, and as the lead guitar emerged from the breakdown and reconstruction in the middle of this version, it simply sang with clarity.

Deodato is actually a pianist, and his electric piano takes the lead in the next track, “Pavane for a Dead Princess”. The clarity was such that I would have had no difficulty in identifying the precise instrument he was using … had I that kind of knowledge, which I don’t.

Album after album it was all pretty much the same. The Moon 310LP just did its job perfectly, while doing nothing to draw attention to itself. That covered selections from Nick Cave, John Coltrane, The Police, the Berlin Philharmonic and even a touch Grand Funk Railroad, some original purchases, some new pressings on modern vinyl. To finish off, I span up the Glenn Gould Silver Jubilee album from 1981 (although most of the recordings date from the 1960s). On side 2 we find the iconoclastic pianist playing some Scriabin, then accompanying Elisabeth Schwarzkopf as she sings some Richard Strauss songs, then finishing of with Liszt’s piano transcription of the first movement of Beethoven’s Pastoral Symphony.

Simaudio Moon 310LP phono preamplifier

Thankfully Gould seemed to be able to restrain himself from humming through the lieder. Schwarzkopf’s precision and power were something to behold, but it was the Liszt/Beethoven that had me tapping my foot (and yes, despite the power of his playing, and CBS’s sometimes extreme efforts with regard to microphone placement, Gould could be heard at the odd moment, singing along). The piano tone was so sweet. Gould tends to be light on the sustain pedal, so every note was clearly delivered, even in the sections with a rolling build-up. And I hardly need say it, but all was all supplied to my system flawlessly by the Moon 310LP.


For this one I put my money where my mouth (or at least my typing fingers) are. After spending quite a few hours having the Moon 310P lift a minute signal generated by a few coils of wire to useable levels and restoring their frequency balance, I have to say I’m at a loss. That loss is how any other phono preamplifier could do a better job.

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