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Equipment Review

December 1999

SimAudio Moon P-5 Line-Stage Preamp

by Marc Mickelson



Review Summary
Sound A soundstaging champ that "retrieves lots of detail" but "doesn’t call attention to itself"; treble seems "just the slightest bit diminished in energy at the very uppermost extremes" while the midrange and bass are "similar in quality: unadorned and solid."
Features Single-ended and balanced inputs and outputs; separate power supply; remote control; bullet-proof build quality and gorgeous looks.
Use Display is very easy to read from across the room; the umbilicals between preamp and power supply are too short to put the power supply very far away from the control unit.
Value No tubes to worry about and sound quality that will make you wonder why you’d want to mess with them anyway.

The story of this review, like that of so many others, begins at a show, HI-FI ’99 in Chicago in this case. A group of us SoundStagers was having dinner at the Berghoff with John Poulin, Lionel Goodfield and Vince Stables from SimAudio as well as a cast of others. We had two tables pulled together, and talk of power supplies and CDs was flying. Lionel leaned over to me and said: "I talked to Doug about having you review our P-5/W-5 combination."

"Sure," I said. "I know the perfect writer for it."

Lionel replied, "No, I’m asking if you want to review it."

I thought for a quick second and then said to Lionel, "I don’t have much experience with solid-state gear anymore."

Lionel asked "You still have your ProAcs, right?" I nodded. "I love ProAcs, and I think you’ll be surprised by how good the P-5 and W-5 sound with your speakers."

About two months later, the preamp and amp arrived -- in boxes that looked worn from lots of travel. Both units (or should I say all three units -- the P-5 has a separate power supply that looks like a component) arrived in good shape, and I understood the delay was due to an update that needed to be done to the W-5 amp. It’s impossible not to be impressed by the external build quality of these two Moon components: thick aluminum faceplates with a slight lilac hue (at least to my color-blind eyes), tight cabinetry, heavy-duty binding posts, RCA jacks and XLRs. They looked bullet-proof -- literally -- and elegant to boot.

So you probably think I immediately put them into my system, fired them up, and all was bliss. Well, not quite. I was in the midst of another review, as I always am, and I also couldn’t get past the solid-state nature of these good-looking beasts. So I tucked them into the corner of the room, where they sat for a week. Finally, I did insert them into my system, connected everything, and left them to run in for a few hours. This review, of the P-5 preamp, will precede that of the W-5 amp. Both pieces of equipment are too substantial to cover well together.

Details and use

The P-5 is about as easy to use as any piece of equipment. It’s remote controlled, has single-ended and balanced inputs and outputs, has a display that’s very easy to read from across the room, is simple to set up, and displayed no abnormalities during use -- none. Its remote has all functions and is large and hefty -- it could be used as a weapon in a pinch. I can’t think of much more to say about using the P-5 except that it works like a charm.

Its circuitry, however, is another matter. As explained on the SimAudio website, John Poulin and crew aimed with the P-5 to design a preamp that would have the shortest possible signal path (9.5" according to SimAudio) with the fewest possible signal-path obstacles. In this regard, they chose to eliminate all carbon-based parts (resistors, pots, etc.) in a zero-feedback design. The volume control is especially noteworthy. It’s an RBG gain device that uses resistors that are selected by a microprocessor-controlled relay network. SimAudio places it at a point in the signal path where, they say, no colorations will be introduced. The P-5’s outboard power supply follows SimAudio’s belief "that small preamplifier signals require a better power supply than do amplifiers." Thus it’s sophisticated and uses SimAudio’s proprietary toroidal transformer. The power supply and control unit together weigh 34 pounds.

The casework of the P-5 is very impressive. Both chassis rest on towers with gold spikes at the bottom, but these are hidden from front view by the thick faceplate. The chassis is said to drain micro vibrations, improving sound. One note in regard to the RCA output jacks on the back: they are on opposite sides of the preamp, so if you use cables like those from Tara Labs that are connected to each other via a short piece of wire, you won’t be able to connect them when using the P-5. However, this arrangement does make routing the left and right output cables from behind the preamp easier, so the P-5, as most things in life, involves tradeoffs.


As I’ve already mentioned, I used the P-5 along with its companion, the W-5 amplifier. Of course, I also used just about everything else I had around here too -- Lamm ML1 and ML2 monoblocks, Lamm L1 preamp, Audio Aero Capitole amp, Mark Levinson No.39 and Linn Ikemi CD players, JPS Labs Superconductor2 and Tara Labs Air One interconnects, JPS Labs and Tara Labs speaker cables. I also used my Audio Magic Tubed Interconnect as well as a whole host of Bright Star Big Rocks and Little Rocks. Speakers were my reference ProAc Response Fours as well as Silverline Sonatinas and Sonatas (review and follow-up in the works). Oh, and how can I forget to mention my beloved Timbre TT-1 2000 DAC?

Preamp and power supply sat on separate shelves, which is all that the two umbilicals between the two would allow. Hey SimAudio, give us a little more slack, OK? I would have liked to put the power supply on the floor and further away from the preamp. On the plus side, the umbilicals are detachable at the power supply, so you don’t have to balance the two boxes while you’re trying to put them on your rack.


The last solid-state line stage I heard was the Klyne System Seven, and I was impressed with it. Enough to want to buy it? Not quite. While the Klyne was never hard on the ears, it failed to seduce me, to draw me into the music and thus make the whole hi-fi-at-home experience an enveloping one. To be fair, however, this occurred over a half-dozen years ago, and I have since heard so much audio equipment that I can’t even recall any specifics about the Klyne preamp’s sound. I’d love to hear it again, however, especially given what I heard from the solid-state SimAudio Moon P-5.

First and foremost, the P-5 is a champ at throwing an immense, populated and fully realized soundstage. We often think this is the domain of tube preamps, which do a much better job than their solid-state counterparts at portraying the soundstage on a recording as unique and credible, but the P-5 proves this isn’t only a feat for tubes. In fact, I’ll go one step further: I was stunned by how well the P-5 helped fill the business end of my listening room with performers. Left-to-right spread and in terms of depth, the P-5 never failed to impress. One of the first CDs I listened to was the remaster of Kind of Blue [Columbia/Legacy CK 64935]; "So What" had a sweep and completeness that were beautiful with the lights off. I also recall listening to Johnny Cash’s Unchained [American Recordings 43097] with the little Silverline Sonatinas, and even with these speakers, the P-5 portrayed a varied wall of sound redolent with instrumental flourishes and JC’s chesty voice. I just love "I’ve Been Everywhere" from Unchained, and so I’ll throw in this plug. One thing you won’t get from the P-5 in terms of soundstaging is the sense that it’s enhancing what’s not there on the recording. In every case, the P-5 was completely believable; in no way would I say that the P-5 does its work in anything but an honest way.

The treble of the P-5 was probably the area of its performance that I worried about the most -- before I heard it, that is. The P-5’s treble avoids ills -- crispiness, hardness, and bleaching of harmonic textures -- and in the process was nothing but accurate and enjoyable. It’s revealing and delicate for sure, but seems to be just the slightest bit diminished in energy at the very uppermost extremes, which may be why I’m not chased from the room with less-than-perfect discs. To give you some idea of this, listen to the recent Mobile Fidelity remaster of The Who’s Who’s Next [Mobile Fidelity UDCD 754]. MoFi really digs the goods out of the master tape on this one, and as you’ll find out, the master tape isn’t pristine. The P-5 lets this be known, but it doesn’t exacerbate it, making low-level listening enjoyable but giving you some room to turn it up too.

The bass and midrange of the P-5 are similar in quality: unadorned and solid. While neither is particularly plump or weighty, they both give ample presence to music, the bass line on "All or Nothing at All" from Love Scenes [Impulse! IMPD-233] having no greater presence or attenuation than Diana Krall’s vocals, which don’t seem particularly resonant or chesty. In other words, the P-5 seems to add nothing to the sound, no extra bass heft and no added midrange splendor. I admire this about the P-5 given its rather accommodating treble: it doesn’t sound washed out or without character, but it equally doesn’t editorialize either.

The P-5 retrieves lots of detail, as I expected, but it does so without calling attention to this part of its game -- you won’t say "Aha! That’s the P-5’s thing." Whenever I want to get a good bead on a piece of equipment, I put my fave Television [Capitol C2-98396] on my system. I’ve heard this disc with so much equipment, and so many times with my current reference rig, that I can always count on it to give me insight into a piece of equipment under evaluation. While nothing jumped out at me when I played Television with the P-5 in use, I did notice that certain more atmospheric parts of it seemed to "appear" from further back in the mix. Additionally, the disc never sounded hot or trumped up, which it immediately can if the equipment leans this way (I’ve taken this disc to CES a few times, to the chagrin of some manufacturers when they hear it on their only-audiophile-recordings systems). In any case, the P-5 is revealing; what it’s not is emphasized, and this is very good news -- and once again surprised the tubehead in me.

I suppose in the end the question on everyone’s mind is how close the P-5 comes to the overused "straight wire with gain" moniker that’s considered the epitome of traits for preamps. Well, the P-5 has a character, which I’ve describe above, but not an overbearing or obvious one. Instead it’s neutral and balanced for sure, but in the end it doesn’t call attention to itself with obvious emphasis anywhere. I was always impressed with its handling of the music I threw at it, never sounding like a solid-state preamp but also never imparting any overt romanticism often attributed to tubes. I liked it from the first listen, and my admiration only grew as I put more hours on it, so unreliably did it shred my preconceived notions about solid-state equipment. I’ve been humbled.

In regard to how the SimAudio electronics worked with my ProAc speakers, I would have to call the pairing a success. I will elaborate more in my review of the W-5 amp, which is in the works, but I can say that the P-5/W-5 combo sounded better with my ProAc Response Fours than any other solid-state electronics I’ve used, I think due mostly to the deft way the treble is handled and its overall lack of embellishment. Again, more to come on this subject.

Compare and contrast

Unfortunately I didn’t have another solid-state line-stage preamp on hand for comparisons, but then I remembered that my reference Lamm L1 is a solid-state line stage of sorts -- it has only a tube voltage-regulation stage. It’s a single-box unit, but it has always pleased me with its suave and natural presentation -- two sonic characteristics that I can’t get enough of.

You can probably guess, given what I say about the L1, how it and the P-5 differ. The Lamm has the ability to get loud but never hard on the ears; as recordings approach the volume and power of live music, the L1 hangs in there. The P-5, on the other hand, will let you know more about the recording itself as the volume increases. Does this mean the Lamm L1 obviously adds to or subtracts from the recording itself? Perhaps, but it sounds like itself at all volume levels. There’s something happening with it that makes it sound, like all Lamm equipment, utterly natural always. Then the P-5 must be doing something additive, right? I don’t think so as it always seems to let the recording, and its ills, shine through. The L1 does sound darker, but not dark overall, while the P-5 has a more neutral flavor. Its perspective is more vivid too, while the L1 is more atmospheric and slightly softer in the way it handles transients.

Overall the two are rather different, but both are musically valid to my ears. If you want involvement and the message to shine through, try the Lamm L1 (which also costs considerably more than the P-5); if you want to hear more of what’s on each recording (and like the idea of remote control), try the P-5.


If you’re an aficionado of solid-state electronics and you haven’t heard this SimAudio gear, preferring to hang with the bigger names like Krell and Mark Levinson, you’re missing something. The P-5 surprised the heck out of me and now goes on my list of electronics to recommend with ProAc speakers (yes, I get a lot of e-mail), especially for those who want less adornment than tubes can sometimes supply. I was delighted by its soundstaging ability and gentle treble, and I loved playing with it. Hearing the soft "tick" of its volume control made me think that the P-5’s $3995 price pays for some advanced technology.

So while I wasn't looking forward to reviewing the SimAudio Moon P-5 or its companion W-5 amp because of their lack of tubes, I’m very glad I was able to hear them. Their sound doesn't resemble that of tubes, but the two components stand on their own merits. And if you audition the P-5 (and W-5), you may, like me, try to devise a way you can own it along with your tube gear and add a little variety to your spicy sonic life.

...Marc Mickelson

SimAudio Moon P-5 Line-Stage Preamp
$3995 USD.
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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