August 2000

Assemblage DAC 3.0 Digital-to-Analog Converter

by Doug Blackburn

Review Summary Sound "Solid, detailed bass; completely neutral mids and highs; and all the detail you should ever want or expect from your music" -- "are you brave enough to deal with it?" Features Well-laid-out circuit boards and internals; multiple inputs including I-squared-S-Enhanced; Signature parts kits and 24/96 filter upgrade available. Use Assemblage estimates three hours of work to assemble the DAC 3.0 from a kit; replacing the stock HDCD filter with the 24/96 filter is strongly recommended; I-squared-S-Enhanced is the best-sounding input. Value High; a top-drawer DAC that's reasonably priced for its performance because you build it yourself.

I completed a review of the Assemblage DAC 2.6 last May, so the DAC 3.0 comes along while the sound of the full-boat DAC 2.6 remains very fresh in my mind. I described the DAC 2.6 as sounding very clean, dynamic and uncolored. It has very good to excellent performance in every sonic parameter. For close to $1000 with all the options, it represented what I thought was high value in an outboard 24/96 DAC, especially for those seeking sonic truth rather than a sonic flavor of the month. But as good as the DAC 2.6 is, it isn’t the only Assemblage digital-to-analog converter. Assemblage offers customers who prefer to buy direct (there are no dealer sales of Assemblage products) the DAC 3.0 as the company's ultimate DAC for the serious audio enthusiast.

The DAC 3.0 is physically larger than the DAC 2.6, and it seemingly has more of everything. The cost goes up to $1499 for the standard DAC 3.0 kit and tops out at $2048 assembled with the Signature parts kit and the Burr-Brown DF1704 24/96 filter replacing the stock HDCD filter. There are a pair of the ubiquitous Burr-Brown 1704 24/96 DACs per channel and a Crystal CS8414 input receiver. The output stage is monitored by a DC servo that nulls out any DC that might otherwise appear at the outputs. The assembly manual contains sections on proper soldering and wire-stripping techniques, and tips on successfully completing the kit. Circuit diagrams are included.

It should be noted that with the supplied HDCD digital filter in place, the DAC 3.0 is not a true 24/96 DAC. The HDCD filter limits the digital bandwidth to a maximum of 48kHz. To have a full 24/96 data path through the DAC 3.0, you must replace the HDCD filter with the $50 DF1704 24/96 filter option. The HDCD filter is socketed and is reasonably easy for almost anyone to replace, even if you aren’t terribly experienced with that sort of thing.

The DAC 3.0 is very impressively built. Each channel has a separate four-layer analog output PCB located in the right- and left-rear corners. The four-layer input PCB fits in between the output boards. The entire front half or so of the chassis is dedicated to the two-layer power-supply-and-control PCB. There are three separate toroidal power transformers. As usual for Assemblage, the PCBs are very purposefully laid out, which contributes to the excellent quoted specifications: THD+noise at -100dB for 24-bit input data and -92dB for 16-bit data; signal-to-noise ratio of -114dB (-117dB A weighted); crosstalk at -120dB. It takes rather large sums of money to exceed specifications like these.

Digital inputs are: S/PDIF (standard Philips/Sony interface for 75-ohm coax) with RCA or BNC connector, AES/EBU with XLR connector, ST glass optical, TosLink plastic optical, I-squared-S-Enhanced using a 13W3 connector. At this time, Assemblage and Sonic Frontiers DACs and transports are the only ones I know of using the I-squared-S-Enhanced interface, which is even better than the older I-squared-S (not Enhanced) interface that appeared on perhaps a half dozen manufacturers’ products. Analog outputs include standard RCAs and balanced output via XLR connectors. There's also an IEC power-cord socket.

The case is finished in black crinkle paint, and the thick front panel is black anodized aluminum. Left to right on the front panel are the source selector button, LEDs indicating which source is selected, absolute-polarity button, polarity LED, power LED (blue), mute LED, mute button, de-emphasis LED (illuminates for a small number of CDs originally made with de-emphasis), lock LED (indicates the DAC is locked to a digital signal on the selected input), HDCD LED and power button.

A kit of a different color

If you read the DAC 2.6 review, you may remember that it was a remarkably easy-to-assemble kit with all of the electronic components already soldered to the PCBs. Assembly consisted of mounting the parts in the chassis and soldering a few wires to the IEC input power module and to the output RCAs. It was not challenging for those who have mechanical and soldering skills.

The DAC 3.0 is something else again. The left and right output PCBs and the input PCB only have some of the electronic components installed. The power-supply PCB has no parts installed. The DAC 3.0 builder will have to install a fair number of electronic components. Assemblage estimates three hours of work for someone with average mechanical and soldering skills. If you are going to build the kit and are contemplating the Signature parts kit, you’ll be much happier if you get this kit when you buy the DAC 3.0. You’ll save lots of time removing parts since many of the Signature Upgrade items can be substituted for the stock parts before installing them.

As with all Assemblage kits, the DAC 3.0 is "guaranteed to work" when you get done with it. If there is any problem, Assemblage technical support will talk you through the problem on the phone. If the problem can’t be resolved on the phone, you send the unit to the repair depot, where it is put into operating order and returned to you. Shipping one way would be your only cost.

Let me make this perfectly clear…

Let me get the issue around the two potential digital filters out of the way right now. Apparently there are a lot of people who did not understand my description of the degree of improvement in sound quality the DF1704 filter offers over the stock HDCD filter in the DAC 2.6 review or in one of my monthly "Max dB" columns. The HDCD filter sucks compared to the DF1704 24/96 filter, OK? Is that completely clear? This question will be on the final, so no excuses! It doesn’t matter whether you are playing 16/44.1 CDs or HDCDs -- they all sound much better through the DF1704 filter. The sound of the HDCD filter in the DAC 2.6 was NOT GOOD. The sound of the HDCD filter in the DAC 3.0 was NOT GOOD. Spend the $50 extra for the DF1704 option. It’s the best $50 you could spend on either DAC. With the DF1704 filter, it was time to put an auto-feeder on the transport so you could just keep listening to disc after disc. The satisfaction and analog ease the DF1704 filter brings is really addicting.

I see stars

On a moonless, haze-free night in the country at a few hundred feet elevation, you can look up into the night sky and see our little corner of the universe with your naked eyes (perhaps through corrective lenses). You can see the sweep of the Milky Way, many stars, perhaps a few planets, and some of what look like stars may even be entire distant galaxies. If the air is still, the humidity low and no strong temperature-induced upward or downward motion of the air exists, the stars won’t even twinkle. Your view is awesome, and you might think it is approaching what you would see from space. But to get a feel for just how much better the view of the stars can be, you need to put yourself out a little. You need to get above 6000 feet elevation on a dry, still night, far from city lights. If you avoid looking up while on your journey to this spot, the first time you do look up you may experience one of life’s most meaningful moments -- a closer view of our universal neighborhood as it really appears without nearly as much interference of atmosphere and artificial light. Everyone who experiences this has the same very powerful reaction that makes your mind race with wonder and awe.

The DAC 2.6 gets you out into your backyard on a night with perfect viewing conditions. The DAC 3.0 gets you to the top of Haleakala, the dormant volcano in the center of Maui, on a dry, still night. In your backyard, you see the Milky Way as a slightly lighter-than-black arc across the sky. On top of Haleakala, the Milky Way shimmers with light and variations in density, and you might even detect a little color in places. I don’t know anybody who would be satisfied with the view of the night sky from their backyard if they could have the view from Haleakala instead. So it goes with the DAC 3.0. If you have the money, this is the view of the music you want because the things that obscure the music become vanishingly small.

Starting at the bottom, the DAC 3.0 is capable of bass that’s as good as I’ve heard from a digital product at any price. Some expensive DACs try to impress with too much bass. Lower-cost DACs tend to be a little less decisive in the bass than you might want in a more expensive product. The DAC 3.0 threads the needle perfectly is regard to the "amount" of bass. What I hear from the DAC 3.0 seems right on the money: loud when the material is loud; great whomping pressure waves when appropriate, and subtle detail and richness whenever appropriate. I can envision a DAC with perhaps a little more pitch definition in the bass, but I haven’t heard one that’s better at anything close to the DAC 3.0’s price. This is bass I could live with over the long haul. Even though there may be fractionally better bass available from products that cost two to six times what the DAC 3.0 costs, the difference is not large enough to be terribly concerned about.

As we climb into the midrange and highs, the DAC 3.0 disappears and leaves only wonderful unmanipulated sound. I just read a review in which the author conjured up the word "creamy" as a positive sonic adjective to describe the sound of a system he’d assembled. Why would you want that when you could have a clear night on Haleakala? Why would you want your music to sound "creamy" if it wasn't recorded that way? The DAC 3.0 leaves no trail and tells no tales. I can’t uncover anything to describe because I only hear what’s on the recordings, at least as much as I can know or imagine what is on the recordings. I certainly know what other components make the music sound like, and the DAC 3.0 doesn’t do any of that.

The DAC 3.0 doesn’t sound fast unless there is some otherworldly transient on the recording. Do you ever listen to live music and think, "Boy, those transients sure are fast!"? No? Me either! Effortless perhaps, but not noticeably fast. I’m troubled by components that sound fast all the time. Music isn’t like that, and you don’t get that with the DAC 3.0. There is a natural feel to transients in the way that they aren’t all the same speed and all extra zippy either. The amount of natural detail the DAC 3.0 delivers from familiar CDs will surprise you. This is natural sound with the ability to convey nuance that lesser DACs homogenize to one degree or another. I can’t give you loads of pretty adjectives about how music sounds coming from the DAC 3.0 because every instrument on every recording I listened to sounds just as it should. I can hear John Hartford change banjos from track to track and even tell when he goes back to a banjo he used on an earlier track. I can hear changes in the studio from track to track. But these kinds of things are all neutral in their effect on the music. They aren’t thrust into your face, making the change in instrument or studio so obvious you can’t get into the music. No, the DAC 3.0 gives you the difference without ramming it into your consciousness. It’s difficult to verbalize just how pleasurable this type of performance makes listening sessions.

The DAC 3.0 is also quiet as all get out -- total lack of noise. Heard about DACs or CD players with tubes in the output stage? Hiss! They are going to have roughly four times the noise level present in a product like the DAC 3.0. This does wonders for spatial presentation. You can get the measure of the spatial character of any recording within minutes. Unlike some digital and other components, the DAC 3.0 does not impart a uniform space/depth fingerprint on every recording. Some CDs are in your face, and some are very distant. Some have a huge soundstage, while others are tighter and more compact. It all depends on what’s on the recording.

Paired with the R.E. Designs SCPA 1 six-channel preamp (using only two channels for stereo) and incorporating the Assemblage D2D-1 jitter reducer and upsampler with a modified Pioneer DV-525 DVD player as a transport, a Belles 150A Hot Rod amp driving the Vandersteen 3A Signature loudspeakers with a pair of powered Vandersteen 2Wq subwoofers, I experienced the highest level of detail, definition, power, control and lack of coloration I’ve ever had in my reference system -- save for the same system with the far more expensive Warner Imaging ER-300MSE mono amplifiers. The SCPA 1/DAC 3.0/D2D-1 combination feeds the rest of the system with a rather incredibly detailed musical signal -- one with stunning pitch definition. I mentioned earlier that I could envision a DAC with a little better pitch definition than the DAC 3.0 alone. Well, combine the DAC 3.0 with the D2D-1 and feed a preamp that can avoid homogenizing the detail and you have yourself a transcendental listening experience. In my case, I was impressed by the degree of precision in those products’ ability to detail closely spaced frequencies, delineating them very clearly, where other products were running these detailed sounds together into a composite rather than preserving what was present in the recording. At the same time, I was surprised that so many commercial recordings capture that level of detail! I never realized how good commercial recordings could be. And I do mean mass-market, non-audiophile commercial recordings.

Tale of interfaces

I tried the TosLink, I-squared-S-Enhanced, RCA coax and BNC coax interfaces and found -- tah-dah -- the I-squared-S-Enhanced sounded the best by a modest margin, and the cable costs just $50. BNC coax sounded next best using a cable that costs almost $300. RCA coax was next best, also with a near-$300 digital cable. TosLink brought up the rear with a $45 plastic optical cable. If you don't have a transport that outputs I-squared-S-Enhanced (Assemblage or Sonic Frontiers are about your only choices), you can get to the I-squared-S-Enhanced format and de-jitter the signal at the same time by adding the Assemblage D2D-1 between the transport and DAC 3.0.

Comparo

As alluded to earlier, the DAC 3.0 is very much a family piece to the DAC 2.6, which sells for roughly half the price in various configurations. But the DAC 3.0 gives you a little more of everything. No one thing on its own would be enough to get you to double your DAC expenditure, but look across the entire sono-scape and you get a much better view of the music, much the same way we get an elevated perspective of the universe from the top of Haleakala. Other DACs give different sonic perspectives. The MSB Link with Channel Islands mods and Monolithic Power Supply gives a romantic, lush, almost sybaritic atmosphere to the music. The feeling reminds me of the prototypical classic gentleman’s library finished in dark woods with brass accents, elegant leather upholstered furniture and the finest in antique accents. The DAC 3.0 is more like our ideal viewing conditions of the night sky, very little gets in the way of exactly what is on the recording. No editorial commentary, just pure clean music.

Los endos II

You could drive yourself mad trying to characterize the sound of the DAC 3.0. One day it’s dry, the next resonant, on the weekend it’s all dynamics and guts. On Monday it’s romantic and soft. Then you realize it’s the recordings, not the DAC. They are all different, not the same. You can’t assign any overall "sound" to the DAC 3.0. It won’t make a lush recording sound dry, and it won’t make a dry recording sound lush. You can chase those sounds if you like, but you’ll get the same character on every recording. The DAC 3.0, and to a slightly lesser degree the DAC 2.6, give you neutrality. Are you brave enough to deal with it?

The DAC 3.0 delivers solid, detailed bass; completely neutral mids and highs; and all the detail you should ever want or expect from your music. At the same time, the soul of the music remains intact -- in fact you find out music has a multi-colored soul, not one that's a boring monochrome. The ability to deliver fantastic pitch definition right down to frequencies that are very close together will keep you revisiting your entire music collection to hear what you’ve been missing all those years -- provided the rest of your system can deliver the goods too. The DAC 3.0 is a solid high-end performer in the truest sense of the term. You could spend more money, get something that sounds a little different, but in no way would the DAC 3.0 be outclassed. If I were shopping for a 24/96 DAC in the $2000 price range right now, the DAC 3.0 could easily be the one.

...Doug Blackburn
db@soundstage.com

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