MOON 390: review

When I fired up the MOON 390 (£4950) and 330A (£3700) by Simaudio nothing stood out or drew attention to itself. Except this: density. Sometimes that overt lack of identifying markers is the sign of a supremely controlled and composed component. Two, in this case. Not surprisingly, the MOON 390 preamplifier and the MOON 330A power amplifier is a match of rare quality. This commentator has not had a two-box setup that cost as much as the MOONs. I have not had anything that sounded as dense and transparently liquid either.

The question quickly presented itself: should I review this as a pre/power combo or should I review just the MOON 390 and use the  330A power amplifier to even the odds with the gear I would use to compare to the 390? After two days of listening it was clear that although I am very satisfied with my Croft Series 7R power amplifier, the 330A was a different beast. It’s also more than twice the money. The Croft 7R is rated at 55 Wpc into 8 Ohms. The MOON 330A is 125 Wpc into 8 Ohms.

Likewise, putting my Croft Micro 25R preamp in front of the MOON 330A revealed how great a pre-amp it really is.

This ties in with cost. As mentioned, the MOON 390 is a preamp with a phono stage, a network player, a DAC, a headphone amp, and even has a slew of HDMI inputs and outputs. It has single-ended and balanced inputs and outputs. It has way more functionality than I would ever need. I looked at that slightly menacing black box and did some math. The MOON 390 costs about €5690. The separate components I will use in this review it comes in at about €4500-5200. By audiophile standards that’s in the same ballpark – and yet another reason to use the 330A amp to power both my own separates and the all-in-one pre-amp MOON 390:

A note: I must give separate mention to the 330A power amp. It is remarkable. It seems to take complete control of all the speakers I throw at it. It is detailed, music has tremendous weight. There’s a grip in the woofers of my Guru Q60s that I don’t think I’ve heard before. At the same time, it has a delicate touch when needed – which is all the time – but the crowning feature of this amp is the way it images and the size and shape of the soundstage. If I had that kind of money, I would buy it in a heartbeat.


When I’d reached out to Simaudio they mentioned the MOON 390 preamplifier and would I like to review it? Bien sûr. Of course, certainly. I would. I will.

The next day they said they would be including the MOON 330A power amplifier.

Green Audio Review is a new gig. I think it is overwhelmingly cool for a company of Simaudio’s size and repute to remember the smaller guys on the circuit. Some of that, I imagine, is because they think the green in my approach is interesting.

I received the MOON 390 and the 330A in late winter. Pre-Corona, and pre a time when most of my listening is now done in a less than quiet household. As it turned out, the MOON 390 preamp is as good at casual/convenient listening as it is at satisfying that loneliest (and futile?) of pursuits: listening to music alone, critically.

The Green Factor

Simaudio offer a 10-year warranty on all their products. Ten years is a long looong time. It’s the most I’ve come across. Schiit offer 5 years, albeit at a much lower price point. A 10-year warranty speaks to the seriousness with which Simaudio go about manufacturing their products. This is gear which is meant to be used, cared for, and cherished for years. That eye toward longevity fits perfectly with the versatility of the MOON 390: you put this in your system and it becomes your system; and you don’t have to replace it. Ever. It is the most comprehensively outfitted preamplifier I’ve handled.

Simaudio are purposefully building their products to last. There is no planned obsolescence afoot here. From the Simaudio website:

“At Simaudio, we are proud to build products that are sustainable, imparting a minimal impact on the environment. We favor responsible suppliers and subcontractors who share our philosophy of reducing our carbon footprint. We offer a 10-year warranty on all our products to respect our sustainability value”.

Music to my ears.

As we’ll se below the MOON 390 is not only a very deliberate and well-built preamplifier. It is also hardware and software upgradable. That means longevity and sustainability. Simaudio do not mess around. And sustainability is not just a buzz-word for them.


Both amplifiers look severe. Their aesthetic is hard-lined efficient. Something austere, but also something very functional and understated modern. They don’t look like jewelry; they look like performance.

I did not pop the hood, but build quality outside is good. Solid. Buttons and knobs feel sturdy. The buttons that control the MOON 390 are made of plastic and so are the convex sides of the front. Beyond that the 390 is relatively conventional in build and appearance: A black aluminum box, ventilation up top and an impressive array of input/outputs around back.

Inside there’s a meticulous attention to detail and trickle-down technology from their flagship products. One of these is the power supply. It is their own design, the Moon Hybrid Power (MHP). Hybrid because the power supply uses both switch-mode and linear technology. Simaudio states that the MHP ensures very stable, very low noise DC output:

“Yes, the 390 uses a special power supply we have created and gave the name MHP which stands for MOON Hybrid Power.  The idea behind it is to get the best from both technologies, i.e. switch mode and linear mode. The switch mode portion allows for better efficiency, but also, more interesting, it is not vulnerable to voltage variations in the line. It can work from 100V to 240V so you can imagine small variations within one’s Mains electricity at a given place has no negative effect. Then, the linear regulation stage allows for more smooth and quieter voltage rail to supply the sensitive electronics inside the 390. Please note that the analog sections and the digital sections are powered by different regulation sections of the MHP.”

This is just an example of Simaudio going to great lengths to increase sound quality. My listening confirms that the trouble has paid off: this is perhaps the most silent preamp I have had in my system. Even with headphones I detect zero noise. – Which is more than impressive when we look at all the functionality that has been crammed into the MOON 390. Both analog and digital.

“Yes indeed the 390 is very quiet…I am sure you have heard many brands mentioning they have galvanic isolation for their USB input to avoid noise coming from a connected computer to pollute the signal into their product. Well, we took that idea and improved on it. To avoid any pollution coming from HDMI or other digital inputs, the whole digital board is galvanically isolated from the analog board… The benefit is a preamp quiet as it can get and clean digital as well.”


Regular readers will know that a big part of avoiding obsolescence is upgradability. This is true particularly when we deal with anything digital. Technology moves so fast that it is crucial for a digital solution like the MOON 390 to be upgradable. Otherwise it will become obsolete before the 10-year warranty is up.

But the MOON 390 is not modular so how have Simaudio gone about this?

“We have designed the 390 for future updates. You can upgrade hardware and software.

Hardware: the MiND board which is already in the second generation. If we launch a third generation, it will be upgradable. We did it with MiND 1 and MiND 2 by creating, what we call, a retrofit board.

Software: the FPGA allows many performance upgrades. Also, the MiND can be upgraded in the software in order to add new functionalities.”


It must be clear now: A simple preamplifier this is not. It’s like a Mytek Brooklyn Bridge in steroids. It’s also double the money and eight times the size. What doesn’t this preamp do? Nothing, basically. But let’s start from the top and move cursorily downwards.

Vinyl is more than covered. It has an extensively configurable MM/MC phono stage, which to these ears presents music with heft and clarity. I only used my Grado Reference Master 1 cartridge. MC testing will have to wait till my pockets are deeper. I found the Gain-setting particularly useful.

There’s a more than capable headphone amp that drove my HD6XX effortlessly and made my LCD-X shimmer.

The MOON 390 is also a network-player/DAC and is Roon Ready. It connects to Wi-Fi via two antennae on the back or via ethernet. I only used Wi-Fi because convenience is queen. – I’m not hung up on formats, but some of you may be. Rest assured that the 390 does them all: PCM, DSD, MQA. Sampling rate up to 32-bits / 384 kHz (USB).

The MOON 390 also has HDMI inputs and outputs to cover everything Home Theater. I’m not familiar with that part of the jungle. I didn’t test it. It’s there and by all accounts it should do a wonderful job.

There are balanced and single-ended inputs and outputs. I found that balanced out via an entry-level Nordost cable sounded marginally better than single-ended out via an entry level Wire World cable. Make of that what you will.

Lastly, the MOON 390 is an incredibly competent preamp an sich: when I used external sources into its line-level inputs the quality and the character of the preamp was anything but subtle. Some audiophiles will say that a preamp you can hear has failed its job of transparency. I used the Hugo2go as a digital preamp directly into the MOON A300 power amp and compared this DAC-direct approach to having the Hugo2go go into the MOON 390 preamp. The Hugo2go should sound cleaner and more transparent, right? Shorter signal paths; closer to the source, etc. It didn’t. It sounded thinner. Using the MOON 390 preamp added not just increased transparency, but also weight, tonal heft, better imaging, and a deeper soundstage.

But we’ll start another place:


My Cayin HA-1A MK2 (€1150) headphone amp sounds smoother than the MOON. This is a stand-alone unit of significant cost and it drives my HD6XX with finesse and make them sound much more expensive than they are. But the MOON 390 does that too, but in other ways. My HD6XX come alive with the same pulsating vigor. The Cayin is not better than the 390, it’s different. The Cayin is warmer, more ambient, and it has perhaps a gentler touch with anything trebly.

The MOON 390 sounds more alive and faster, and much denser and controlled. It is more detailed than the Cayin and it has better low-end extension and grip. Akasha System and the Echo Lost album has a tauter bottom end. In comparison the Cayin is soft-pedalling. The Cayin makes the album hazier at the edges, mirage-like, and with a greater sense of space. Both offer a very satisfying listen. But if you’re after density and precision the MOON 390 is your man. As ever, it comes down to personal preference, the headphones you’re using and the music you’re listening to. I prefer the Cayin with something like Nils Frahm’s Felt or Spaces. But with most electronic music and well-recorded jazz or rock the MOON is preferable.

The sonic difference between the MOON 390 and the Cayin (detail, control, balance vs. warmth, ambience, tube-glow) is turned upside-down when I plug into the Ragnarok 2 (€1549) from Schiit. The Ragnarok 2 has more bubbly vitality. Tonally the MOON is richer and denser. Detail retrieval is about the same. Bass grip, if not extension, is better on the Ragnarok 2. It makes my HD6XX regular puncheurs. Normally I find the HD6XX well and smoothly extended in the low end. They have never really been a bass-punchy headphone for me, but rather a headphone that has a wonderful seamless frequency extension, including velvety bass. With the Ragnarok 2 the HD6XX are suddenly punchy as hell.

The richer tone and density, the gravitas, of the MOON 390 is exactly what I prefer with the Audeze LCD-X. Compared to the Ragnarok 2 the LCD-X out of the MOON are meatier, more liquid. The Ragnarok 2 makes them more x-ray and a bit thinner. That works great with well-produced music. But the MOON has that bit of tonal warmth that make the LCD-X an absolute delight to listen to. Still very transparent and dynamic but with an affable warmth I always enjoy.


The phono stage is firstly crisp, in the best sense of the word. Second and third: very detailed and dynamic. Listening to Kashmir’s Trespassers it is mostly the midrange and treble that stand out. Bass-shy? No. But not bass-slamming either. And still with that innate quality of the MOON: density, weight.

When I switch to the Croft Micro 25R and the eminently capable phono stage onboard I get a bit of Croft-cream in my MOON-cortado. Perchance that is the tubes doing their thing. But I also take a slight hit to detail retrieval. Slight.

The Croft is a very good preamp, but many – me included – view it as a very good MM phono stage first, and a preamp next. At €1850 it is remarkable. It is completely analog and is the essence of stripped-down functionality. The MOON phono stage offers more detail. I find it to be more dynamic as well. It has a wonderful midrange clarity. The Croft is more lush, romantic, which makes Kashmir and The National sound better through the Croft. But, likewise, make Barker’s Utility sound denser and more cleanly satisfying the MOON 390.

Kashmir’s Trespassers appeared somewhat weak in the bass. I switch to Trentemøller’s debut long-player, The Last Resort. That first track never gets old. Compared to Kashmir this is a fuller sounding recording. Via the Croft I get a full and lush sound. Going back and forth I find the bass to be just a tad undefined on the Croft 25R.

Take Me Into Your Skin is punchier on the MOON. The bass is better defined and more extended. There’s more detail so we get a clearer sense of the little clicks and clacks in the recording. The lushness of the Croft is gone but exchanged with better control. The tonality of the Croft phono stage is warmer than the MOON 390. The 390 has a tonal character that is somehow slimmer, but with greater density. Sharper. Like the difference between fat and muscle; bourbon and whiskey.


Soundstage. The MOON 390 consistently painted a clearer, taller, wider, and deeper soundstage than my separates gear. It started with imaging. Vocals were right in front of me, I could touch the voice hanging in the air before me. It was pin-point. And this was evident on both the Guru Q60 and my Buchardt S400.

That’s the first conclusion.

The second is solidity. I come back to this word, but the MOON 390 has a density to its sound that is remarkable. Juneunit’s wonderful ambient techno has exceptional weight. Not as in lumbering or clumsy, but as in massive liquidity. My separates sound perhaps lusher, warmer, but also, strangely, thinner. The MOON 390 has a seamless heft to its sound that stems, I propose, from its all-in-one design. Like how a pair of active speakers often sound exceptionally composed compared to their passive brethren.

Speaking of brethren. Satyricon’s latest album, Deep Calleth Upon Deep, their best since the early days of The Shadow Throne, have never sounded so muscular and controlled. The track To Your Brethren in the Dark is a modern (black) metal masterpiece. With lesser source-preamp components the double kick drum and intricate guitar pieces comes across as muddled. With the MOON 390 there is a tightness and low-end clarity I haven’t heard before. That continues on the track Deep Calleth Upon Deep. A busy track which the MOON keeps firmly in an iron-grip. But velvety so…

…because the MOON 390 also does detail and smoothness like I am used to from my Croft separates. In fact, the DAC and streamer in the MOON consistently outperformed my Node2i and Gungnir Multibit for detail retrieval. The Node2i/Gungnir might be a less taut combination, more forgiving of source material. But the MOON’s dense and detailed sound is precisely not hard or fatiguing.

Streaming Lifeforms, The Future Sound of London’s 90’ties masterpiece, shows me the generous nature of the MOON 390. The 390 lets me hear the music with all the inner detail I could wish for. It is clearly clearer and gives me better instrument separation than the Gungnir Multibit. The Schiit is less etched and is the more forgiving. The MOON 390 is clean and composed, but never harsh. Going Node 2i into Gungnir Multibit into the line level of the MOON has few benefits. If any. A more non-fatiguing portrayal of Lifeforms, maybe? A slight uptick in ambience? But it is not really a concern. The MOON 390 is too composed and balanced for that. Besides, with the Gungnir you lose more: dynamics, detail, separation, and that enormous and enormously precise soundstage.

Hugo 2/2go

At the end of my time with the MOON I reacquired the Hugo 2. The release of the 2GO module assured that.

I queued up Harvest Moon by Neil Young and went back and forth between the Hugo 2/2go (€2189+€1195) acting as a DAC-streamer plugged into the line-level input of the MOON 390 and the onboard streamer-DAC in the 390. I hold DACs from Chord in high regard and what I discovered was, I think, unexpected and another win for the MOON.

Harvest Moon is a smooth album and I think one of Neil Young’s smoothest sounding. It’s also one his best and most accessible. His voice and guitar are rich. If you want to get into Neil Young, this is a great place to start. As is the greatest compilation album of all time, Decade.

Harvest Moon via the Hugo2go gives me more attack on Neil’s guitar. His vocals are a bit more prominent/forward. On the MOON 390 I get a rounder, fuller sound. There’s more tonal weight. I also get a fuller guitar sound. Neil Young uses a big Martin D-45 and that big and wonderful body sounds fatter and more reverberant with the MOON.

Concurrently, the harmonica on From Hank to Hendrix is softer, smoother, less gratingly grained on the MOON 390. On the Hugo2go it is more immediate, vivid.

One of the things that surprised me most about this comparison was that detail retrieval and separation – which I’ve always thought were particular strengths of the Hugo 2 – appeared in fact equal.

Please bear in mind: this is a game of nuances. Overall, the MOON is tonally richer than the Hugo2go. But these differences are small. To the extent where when I forgot what was currently handling playback, I couldn’t tell them apart. They are much more similar than they are different. And one isn’t better than the other, just very slightly different

I find this to be one of the most impressive findings in my time with the MOON: that as an integrated and full-featured unit it could compete with what is arguably one of the best DACs under €3000. And certainly the best I have at my disposal. Detail retrieval, separation, texture, naturalness is absolutely nailed by the MOON 390. There is a terrific DAC and streamer onboard here.


I think the NAD C368 and the Quad Vena II Play are both good integrated amplifiers. At their price-points they are superb. But compared to the MOON pre-amp extraordinaire they are entry level boxes.

Every time I compared their various features – DAC, phono stage, headphone amp – to my stand-alone units they couldn’t compete. E.g. the Asgard 3 drove my headphones better than either integrated.

Not so the MOON 390. It consistently equaled or, mostly, surpassed my best stand-alone units. The Cayin sounded different but not better. The Asgard 3 sounded different and worse.

Effortless is a word I sometimes use to describe gear that I really like. And effortless is how this preamp feels like in daily usage. These are challenging times for everyone and the way I’ve listened to music and evaluated this amp is tied up with the current crisis. This is listening done mainly Corona-style.

I’ve connected various sources, like a turntable, other streamers, other DACs, even a CD player. But with kids in the house and a new value quotient on convenience (streaming Roon direct) vs. tactility and vinyl hygge, most of my listening has been done by quickly, simply, effortlessly and fuzz-free firing up Roon. Normally I like powering on my Croft tube amps and waiting for them to cycle up and adjusting volume for both channels and putting records on the platter and cleaning them etc. With the MOON 390 getting music to simply fill our house in literally no time proved to be the most valuable function of this preamp. Not the DSD/MQA decoding. Not the HDMI capability. Not even the excellent phono stage or the ditto headphone amp. Just playing music and controlling volume from my phone was the real miracle.

In one – albeit expensive – box I get the same effortless streaming functionality as my Sonos speakers and better performance than all my carefully matched separates put together.

To me that is the sign of a special product. You get what you pay for and with the MOON 390 what you get is exceptional.

A Green Award effortlessly earned.

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Trackbacks & Pingbacks

  1. […] I connected the Buchardt S400 to a formidable pre-amp/power amplifier combination from Moon by SimAudio; the 390 and A330. My thoughts on both of those exceptional products can be found here.  […]

  2. […] There’s a longer review of the MOON 390 here. […]

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