A Tale of Two DACs – Lab12 DAC1 Reference Versus Linear Tube Audio Aero DAC

Well, actually, it is three if you count the internal DAC in my Marantz SACD 30n player.

I’ve had this Marantz digital player for a couple of years. It retails for about $3500. I do like it quite a bit. It is rather hefty and solidly built. Plus, it does a lot of things well: plays CDs, plays SACDs, does internet radio, and has Bluetooth reception capability. Its sound is smooth and fluid with virtually no digital edge and glare, having been tuned by the Marantz Sound Master. It has two digital filters: a smoother default Filter 1 that gives that nice natural, slightly polite Marantz sound signature, and a Filter 2 that hints at a cleaner, clearer, maybe thinner sound. And it has a SPDIF digital output, allowing it to used as a transport.

But a few months ago, I started to wonder if there was more out there. Could I go beyond that smooth, likeable, slightly polite Marantz sound? Could I get more from a separate DAC? What more could I want? More detail, more transparencyTransparent / Transparency - A clear view into the recording space, no opaqueness, just openness and clarity., more dynamism—all while keeping that natural fluidity of music. Can I have both detail and musicality, or do I have to stray into a land of edgy, harsh, cold digititis to get more? We’ll see.

So I did my research, (an old, well-ingrained habit from frugal days of yore), and read lots and lots of DAC reviews. After many, I concluded that I would be happiest trying R2R DACs and even tube output DACs. (A few years ago I had a Cary tube power amp, and I still very fondly remember its lovely, musical sound.) Using my budget and geographical location, I narrowed down a list of potential candidates to three: the Lab12 DAC1 Reference (msrp $3290), the Linear Tube Audio Aero DAC (msrp $3950), and the Audio Mirror Tubadour IV (msrp $5000). Sorry, I’m retired. I love it. I live comfortably, but not extravagantly. This is my budget.

Based on my past Cary tube amp experience, and that I presently use a Conrad Johnson Premier 17 LS preamp, one might say I do gravitate toward an organic tube sound. Also, I might add that my speakers are Martin Logan CLS electrostats. I love their transparency. But, as much as I love them, I admit that they do have a lower treble “glare” that I feel the need to ameliorate. This factor certainly does contribute to my appreciation of tube audio components.

The first DAC.

Because it was the least expensive of the three candidates, the Lab12 DAC1 Reference seemed like a good place to start. If it was perfect and did everything I wanted, then I could just stop there and call it a day. I contacted a Lab12 dealer and asked about auditioning the DAC1 Reference. It turned out that he was no longer a Lab12 dealer. But he still did have one DAC1 Reference demo model in house, and kindly was willing to ship it to me to let me audition it. (He even hinted that, because it was a demo model, he could price it very attractively—though we never did actually discuss what amount.)

Once I received DAC1 Reference, I connected into my CJ preamp using the exact same Audience OHNO interconnects as the Marantz player. I wanted to keep everything as even as possible and minimize any variables when comparing it to the existing Marantz player. After seven days of almost continuous listening, being on 8-10 hours per day, it turned out that the DAC1 Reference was not as warm as I had expected. It was warmish, full, musical but also clean and more revealing than the Marantz. It had a really nice mid-range and delivered excellent space and ambience without hard edges or sharp transients. By comparison, the Marantz seemed a little bit flatter and musical notes sounded less dense with less instrumental texture. Through the Lab12 a cello sounds more detailed and deeper; a piano sounds more forward with slightly more body and texture. Recordings of pianos revealed that this instrument makes notes with strings but it also has a body of wood with a metal skeleton. The DAC1 Reference conveyed more of that wood body. Also, the DAC nicely revealed plenty of space and studio details but without emphasizing air and ambience in a clinical, electronic hifi manner.

At this point I should warn you, this review is going to become rather repetitive. From my listening notes, I found that I began to use the words “a hair more,” “a tiny bit more,” “a hint more,” “a fraction more” again and again. In general the Lab12 DAC was a hint more articulate; everything sounds slightly fuller, and slightly rounder. Bass was a little deeper, tighter, richer, and one might conclude better. Music in general was more propulsive, more dynamic, and thus more interesting. But these differences were certainly not night and day. They were audible and definite, but slight. Yes, they were there, and with the Lab12 there was more ‘there’ there—but not by much.

The DAC1 Reference allowed better separationSeparation - The ability to keep instruments distinct from each other, so complex passages don’t blur together. and spatial depth than the Marantz, but only by the tiniest amount. I did find that that the Lab12 was better at taming stridency than the Marantz, ever so slightly. The DAC would soften that top edge just a hair to make music more inflected, nuanced, and lovely. One particular recording I listened to very intently was the Bruckner Symphony no. 8 with Gunter Wand conducting the Symphony Orchestra of NDR Hamburg (EMI/DHM CDS7 497182). This a live recording of performances in Lubeck Cathedral. Through the DAC1 Reference, the CD sounded slightly richer with more density given to instrumental sounds. The tonality was very similar between the DAC and the Marantz player, but the DAC allowed a tiny bit more space, separation, and air to come through. The Marantz seemed a tiny bit flatter, more restrained, and more homogeneous. The music of this huge symphony was slightly bigger, more open, and more three-dimensional through the Lab12 DAC.

I listened also to different recordings of Beethoven’s Waldstein piano sonata by Stephen Kovacevich and Richard Goode. Again, the Marantz seemed to be a tiny bit more homogenized, flatter, softer, less rich and less spacious. The DAC sounded a smidgeon less congealed, less restrained, more expansive, and more textured. In general the Marantz was barely less articulate, less dense, less rich, and less spacious. The Lab12 sounded clearer, wider, more articulate, and ultimately more interesting.

Then I had the crazy idea of switching to Filter 2 on the Marantz. After this switch, the tonality of the two units seemed to be exactly the same. Where I was finding the differences before with Filter 1 to be just barely noticeable but definite, now any differences were even less noticeable if that’s possible. (Talk about splitting hairs.) Maybe the DAC was a fraction of a hair more open. Maybe the Marantz was a fraction smoother and less revealing. But these differences were so slight as to be virtually imaginary.

I should tell you that I was also auditioning several digital SPDIF cables. I will discuss these at the end of this review. One or two could increase the distinctions between the DAC1 Reference and the Marantz to a hair’s width. The others resulted in the two units sounding just about identical. Oddly, with certain digital cables, the Lab12 unit would sound more detailed but also thinner and less full. With these certain cables, the sound of a piano through the Marantz seemed to have more body, more wood, but less string sound than the DAC. With these same cables, the Marantz won in the mid-range department, and the Lab12 seemed a hair more detailed, but cooler and less full than the Marantz. Cables do matter.

So, what to do? I concluded that the Lab12 DAC1 Reference is definitely better than my Marantz SACD 30n. But. The DAC1 Reference was heading in the right direction—giving me more detail, more space and air, more texture—more of just about everything. But only by a hair, a tiny bit, a fraction. If I had to quantify it, I’d say the benefits were so slight as to be 1-2 %. As I told the generous dealer who allowed me to audition the Lab12: the Lab12 DAC1 Reference is very very good, but—I guess—the Marantz SACD 30n is just about as good. Then I had a tough decision to make. The Lab12 is certainly better, but by how much? I already own the Marantz. It will cost me zero new dollars because it’s paid for. I know all about the law of diminishing returns, but geez! Is a 2% improvement worth over $3000? I was very surprised. With great appreciation, I sent it back.

The second DAC.

Linear Tube Audio has a nice in-home trial program, but it’s not free. You order the LTA Aero Dac, pay for it, they hand build it for you in 3-4 weeks, and then they ship it to you for free. You must keep it for at least 15 days but not more than 30 days as audition. If you don’t keep it, there is a 5% restocking fee.

So I ordered an Aero DAC on 5 March, and it arrived on 4 April. One of the nice things the LTA people do for you is they burn in a component at the factory for 168 hours. The Quickstart Guide states also that “full burn-in occurs after 300-400 hours of use.” To date this Aero has been on for over 330 hours. (I kept track.) So, I hope and believe that the sound signature I hear from this DAC is pretty close to the way it will sound for the rest of its life. One more thing, all the reviews I had read of the LTA Aero DAC said that its stock rubes are NOS GE 12SN7GTA tubes. When this unit arrived the two included tubes were NOS RCA 12SN7GTA tubes. It was my lucky day.

Again, I hooked up the Aero using the same interconnects as were coming from the Marantz SACD 30n. I was trying for a fair comparison, an even playing field here. So how does this DAC compare to the internal DAC of my Marantz player? It seems wider, deeper, fuller, more solid than the Marantz. One word I kept coming back to in my notes was “robust.” There was little to no thinness, no leanness yet there was more detail and space. The mids were more rounded and fleshed out, fuller, more substantial, and more solid. There was more differentiation of sound textures with longer decays. The Aero DAC allows more space and depth without emphasizing air (or treble). The soundstageSoundstage - The overall size and shape of the musical “space” a system creates, including width, depth, and height. was more upfront and yet also deeper. It was as if four feet of soundstage had been added in the front and six feet in the rear, compared to the Marantz.

Another word I kept coming back to using in my notes was “dimensionality.” Compared to the Aero, the Marantz made instruments sound a bit two-dimensional and narrower. Through the Aero, music is more interesting, less polite. Bass is ‘heavier,’ that is bigger and lower, and more robust. Wait a minute — does this all sound familiar? Have you heard this before? Well, yes—sounds like the Lab12. But now the differences were much more noticeable. Again, it wasn’t night and day huge, but it was more demonstrative, more obvious—not slight or marginal. As much as the Aero was bigger and wider, music was also more subtle and delicate.

The Lab12 DAC was no longer in-house, but in my notes I attempted a comparison of these two DACs. I wrote that the Lab12 DAC1 Reference had excellent warmth and tonality; the Aero DAC has the same but with more depth, space, and dimensionality. Playing the same cello and piano recordings as before, I felt the LTA sounded especially natural with better dynamic subtleties. Through the Aero, music seemed to have more micro-dynamic shadings and more soft nuances. One of my favorite pieces involving both cello and piano is the Ravel Piano Trio, especially the slow passacaille movement. When listening to this movement through the LTA DAC, the music was so full of delicate nuances, differentiated textures and details—it sounded as if it was slowed down. I felt like I was hearing so much more. During one passage—I wrote in my notes—the pianist sounds like he is in a meditative trance. And the cello and violin sound wonderful, very textured with evident wooden bodies to these instruments. This music sounded lovely, natural, moving yet detailed without being the least bit strident or sharp, cold, or aggressive. I don’t think the word warm is correct here. To me that word implies that some artificially thick quality is being added to the signal, and maybe some high frequencies are being rolled off. I believe the best descriptor for the LTA Aero is “natural.” The Aero sounds natural and detailed with solidity, weight, and presence.

I tried some jazz. I have a JVC XRCD of the Bill Evans Trio Waltz for Debby. Listening to Evans’s piano in the past and through the Marantz, I have often felt the piano sounds somewhat “brittle” even on this very good CD. Listening to this CD through the LTA DAC, the piano sounded fuller, with more wood-body tone—not brittle, not thin. The Marantz played the same notes but they sounded more two-dimensional and “tinkly” with shorter decays. Through the LTA Aero, even the audience applause was more dimensional and less flat. Among the three members of the trio there was more physical space and separation, but more musical connection. The give-and-take interplay between bass and piano was more apparent—with more “boogie.” It was all less laid back. And Paul Motion’s cymbals sounded more real—like they were made of fairly thick spun brass, not aluminum foil or tin cans. I switched to the Keith Jarrett Trio’s recording titled Keith Jarrett at the Blue Note, 1st Set. No more polite, reserved Marantz sound signature. The Aero is a good bit more dynamic and “rocks” when the trio gets going. The drums have more body, more weight, and solidity. The bass was tight, deep, and full. I wrote ‘real.’ The trio is bigger and more dimensional, more spread out, and more substantial. Jack DeJohnette’s drums had wooden cylindrical bodies under the drum skins, and they were precisely located in space. Even the applause sounded less crisp and more embodied. By comparison, the Marantz sounded pretty nice but less deep and less wide, and definitely less real.

I was enjoying the jazz so much, I kept going. Up next was the Keith Jarrett Trio’s The Out-of-Towners. It was more of the same: the Marantz was smooth and had an excellent tonal quality, but seemed more reticent, more constrained, more muted with less dynamic range. (You don’t notice this constraint until you do a comparison—it sounds just fine alone, quite nice in fact.) The Aero was more dynamic, heavier, more impactful, and had more “boogie” factor. The Aero gave a bit more depth and more spread with more differentiation among the three trio members. There’s another word I kept coming back to: “differentiation.” I mean separation in space and distinction of timbral textures. The Aero just plainly does more of it. Through the LTA musical notes have more body, texture, and fullness. DeJohnette’s playing of the cymbals sounded less monotonous and more embodied. The Marantz emphasized the tap of the cymbal. The Aero gives you the tap plus the shimmer—a kind of metallic meat on the bone with a long decay. And on Gary Peacock’s bass, the Aero digs deeper, and has more ”grunt.” In general the Marantz sounds very nice indeed, smooth and fluid. But by comparison, you realize it is just a little too polite.

Another CD I played a bunch and compared back and forth was Diana Krall’s Live in Paris, particularly the Joni Mitchell song “A Case of You.” (Is this an “audiophile favorite”? Overdone and over-referenced? Oh well, I must have missed that memo.) The LTA DAC much better revealed that Krall was singing with several different voices during the song. There was what I called a gospel voice. There was also a child-like, coquettish voice. There was also an annoyed lover voice, and even a crooner voice. The Marantz smoothed over and barely hinted at these differences. The LTA manifested these distinctions. And very importantly, the Aero gave the song more emotion: the sense of loss and regret—of what had been and now was gone—was more present in Krall’s interpretation of that song.

Then, for a lark, I left the comparisons behind and tried out some of my personal Spotify playlists received from my iPad through an AudioEngine B1 Bluetooth receiver, then outputted through Analysis Plus optical Toslink into the LTA DAC. (That’s a mouthful, but it works reliably and very conveniently.) I know the sound of these songs really well, often using them for warming up my system every morning, every day. Holly Cole singing “Jersey Girl”—whoa! She has never sounded this sexy, this sultry before. (My recollection was that through the Marantz, she sings it very competently, very nicely, but not alluringly.) Wow! Cole is almost purring into the microphone. Spotify has never been this much fun before. (I had always thought it sonically challenged. Not anymore.) With the Aero the music on these playlists is now more emotional, more meaningful, more . . . beautiful. The playing of a piano is much more inflected, more poignant, and reveals more rubato. Music seemed slowed down, thus I could hear every nuance, and I had a much deeper emotional connection to the music. This part is embarrassing: in my notes I wrote that I “grunted” with amazed satisfaction at what I was hearing.

Now here is something strange. At this point in my note taking, I started writing in general about how beautiful, articulate, nuanced, and moving the music was. I gave up on details of this or that element of the sound signature. I wrote: “never has JS Bach sounded more like a genius.” “Yo Yo Ma is here in the room.” “I don’t want to stop listening.” Lunch went out the window. Hunger went out the window. The clock went out the window. The time of day—who cares. Doesn’t matter. I wasn’t writing about how the music sounded. I was recording how it made me feel. All this music was just more natural and relaxed and present—and it was a positive joy to take it all in. I even postponed ending this listening session to eat supper until 8:30 PM.

Next day. Okay. Back to work. I have a playlist titled Audio Evaluation II. On it are lot of pieces and songs that are chocked full of spatial and tonal details, soundstage depth and width, ambience and air, and excellent tonality. It is a real mishmash of classical, jazz, rock, solos, duos, trios, combos, orchestral works, and chamber works. If a piece has extraordinary sonic detail information and I like it, I put it on this list for concentrated, intentional listening. Here are some short takes. On Cream’s “I’m So Glad” from the Royal Albert Hall London May 2005 live album, the audience applause intro is way outside the speakers. And the separation and counterpoint between Bruce’s and Clapton’s vocals are much more clearly but naturally differentiated. On the Modern Jazz Quartet’s “Trav’lin’ ” from the Plastic Dreams album, John Lewis’s piano finally sounds like a good sized grand piano and not a child’s, tinkly miniature piano. On the song “Actual Proof” by the Marcin Wasilewski Trio from their Live CD, the trio is so widely spaced, so vibrant, and so manifestly present that they inhabit my listening room.

I have a separate playlist called System Showcase that I hope truly shows off my system’s ability to depict space, depth, and ambience to an impressive degree. I hope. In JS Bach’s Fugue no. 7 from The Well-Tempered Clavier Book 2 played by Evelyne Crochet, the piano manifestly has excellent body and solidity. In Francesco da Milano’s “Fantasia No. 42” on La Serenissima II (Lute Music In Venice 1550-1600), Jakob Lindberg and his lute are set deep in the recorded studio space, and his occasional breathing seems to come from a head and chest—not just a nose. In the Kyrie Eleison I section of Johannes Ockeghem’s Missa Prolationum as performed by the Hilliard Ensemble, we hear not just the sounds of voices. We hear the sounds of bodies producing voices producing sounds of singing in air, all in a resonant palpable space. And yet there is not a whiff of chilly, hard, clinical, high-frequency ambience.

Enough snippets. Let me try to summarize. My Marantz player gives a very nice, smooth depiction with good tonality of music that is pleasant, likable, a little soft, and one might say too restrained. The LTA Aero DAC fleshes things out with more dimensionality, more bass, warmer mids, and greater solidity to instruments. The Aero also reveals more width and deeper space with better differentiation of the various producers of sounds. From the analog output of the Marantz SACD 30n, music seems a little two-dimensional and lifeless by comparison. Finally, I might say the LTA Aero DAC finds (or reveals) any spatial and tonal details in a recording and manifests them—but in a very natural, unforced manner without exaggerated precision.

Long-winded and overly thorough am I. Probably too thorough. Let’s wrap this journey up. If the Lab12 DAC1 Reference was 1-2% better than my Marantz SACD 30n, then I’d estimate that the Linear Tube Audio Aero is 15-20% better. It is just that much more emotional, more involving. It’s not so much how it sounds as what it does. Yes, it sounds wonderful. What descriptors did I write: robust, dimensionality, natural, differentiation. I should add textured, embodied, spatial, emotional. To my feeble and frugal mind, these are worth paying for. After all, what is the point of music? Is it something you just nicely listen to? Or, is it to move you. To affect you. To involve you. So I emailed Linear Tube Audio and said this Aero is not coming back.

But what of the Audio Mirror Tubadour IV you may ask? I apologize. These three components were potential candidates in a search for a DAC that gave me what I was seeking. I would go to a second only after the first did not quite work out in my system. I would go to a third one only after the second did not work out. But it did. Thus, search completed. I did not promise to evaluate all three. Sorry. When and if I found a DAC that gave me everything I was seeking, that was it. Case closed. Journey over. (Now, to listen just for fun.)

Addendum: digital cables auditioned.

Auditioning these DACs, going from the digital output of my Marantz player to each DAC, I tried seven different digital (SPDIF RCA) cables. Two of these I already owned from the old days of when I had a Theta DS Pro DAC and a Sony SCD-777ES player. These two pre-owned cables are MIT Terminator III and HAVE Canare LV-61S. The others I borrowed from The Cable Company. I shall comment rather briefly on each cable.

• MIT Terminator III: very good, natural and nuanced, lacks the tiniest bit of space, air, and detail. But conveys excellent body and substance.
• Kimber D-60: also very good, but a little lightweight and maybe too crisp. It is just a tiny bit on the analytical side.
• Shunyata Gamma: too clean, too thin, lean, crisp, and lacking in tonal body. If you want more analytical detail that lacks density, go for this one.
• Voodoo Silverstream: surprising because I expected a bright “silver” sound, but instead it was rather ‘vanilla’ sounding—that is too constrained and monochrome.
• Cardas Parsec: way too thick sounding, too warm, obviously lacking details that should have been present. It reminded me very much of the old Cardas Golden Cross interconnects.
• HAVE Canare LV-61S: sounded oddly too emphatic, too hifi as if someone had turned up the bass knob and the treble knob, but the two regions seemed disconnected.
• DH Labs D-750: probably the best of the bunch; it seemed appropriately revealing of spatial and tonal details, but not at the expense of body or fullness.

Take care,

Hoodman