AOM Logo May 1997


Some Assembly Required
The Assemblage DAC-2 D/A Converter


Andrew Chasin, Anthony Kershaw

The Parts Connection, a division of Sonic Frontiers, has been supplying high-quality electronic components to audio hobbyists since 1987. In 1989, they took the next logical step and began selling entire audio kits for assembly by the Do-It-Yourself enthusiast. Their first digital product, the Assemblage DAC-1, was released in 1995 and went on to garner many accolades in the audio press due to its excellent price/performance ratio. Luckily, for consumers of digital audio components, the rapidly increasing performance and decreasing cost of digital processors has allowed manufacturers to incorporate technology into their products that budgetary constraints simply would not have allowed a scant one or two years ago. Witness the recently released follow-on to the DAC-1, the aptly named DAC-2. A complete redesign rather than an upgrade of the DAC-1, the DAC-2 incorporates dual 20 bit Burr Brown DACs, the Pacific Microsonics HDCD decoder/filter chip, an improved power supply and better quality parts in the signal path. Kudos to Sonic Frontiers for keeping the price of the DAC-2 in "real world" territory, the DAC-2 ringing in at $499 for the kit and $549 fully assembled, a mere $50 increase over the price of the DAC-1.

Technicalities
For the most part, the DAC-2 isn't a showcase of technological breakthroughs, but rather a product based on technologies that have proven themselves over the long haul. To wit, the DAC-2 employs the Crystal CS 8412 input receiver, a receiver that has been utilized in many highly-regarded DACs. At the heart of the DAC-2 is a pair of Burr Brown PCM-1702 20 bit DACs (one per channel), a chip that has traditionally seen duty only in more expensive processors. Although HDCD-encoded discs are still relatively rare, Sonic Frontiers has chosen to include the Pacific Microsonics PMD-100 HDCD decoder/filter, making it one of only a few DACs in this price range to make use of this chip. A clear indication that the engineers at Sonic Frontiers have their sonic priorities straight is that the DAC-2 performs the 6dB attenuation of non-HDCD encoded discs (required of all HDCD licensees) in the analog rather than the digital domain. Attenuation in the digital domain would result in the loss of 1 bit of precision from each digital sample, while attenuation in the analog domain allows the DAC-2 to take full advantage of the 20 bit resolution of the Burr Brown DACs.

The DAC-2 improves upon the power supply of the DAC-1 with the addition of more filter capacitance and three more voltage regulation stages, for a total of eight. Improvements have also been made to the analog output stage, which now contains the Analog Devices AD817 output buffer as well as high-quality Holco metal film resistors.

A parts upgrade kit, which includes MultiCap capacitors, Caddock metal film resistors, Kimber silver hook-up wire (as opposed to the Kimber copper twister pair supplied with the stock DAC-2) and dampening material to internally damp the DAC-2's chassis, is available from The Parts Connection for $149. Our review sample did not include this kit.

Picture Of DAC-2From left to right, the front panel of the DAC-2 features a phase inversion toggle switch, a red LED which illuminates when an HDCD disc is being decoded, a three-position toggle switch for selecting one of the DAC-2's three digital inputs (coaxial BNC, RCA and Toslink), and a green LED which illuminates when the DAC-2 has locked to a digital source.

The rear of the DAC-2 sports a detachable IEC AC power cord, input jacks for the three digital inputs and a pair of gold-plated RCA output jacks. No power switch is provided since the DAC-2 is meant to be left on at all times.

Although the DAC-2 is small in stature, measuring a mere 9 ½" x 2" x 7" (W x H x D), its rugged black metal chassis and ¼" thick brushed aluminum front panel give it a solid look and feel.

Assembly
While the DAC-2 is relatively easy to assemble (the main circuit board is shipped almost completely assembled), several steps during the assembly require you to solder components to the DAC-2's printed circuit board. For those who have never soldered an electronic component to a circuit board or for those who need a bit of a refresher, the DAC-2's construction manual contains a clear, concise introduction to making correct solder joints. If you don't have a lot of confidence in your soldering skills, here's a suggestion: before purchasing a kit like the DAC-2, drop by your local Radio Shack and buy a small, inexpensive circuit board, a package of assorted resistors, and a foot of resin-core solder (total cost about eight dollars) and spend some time soldering the resistors to the board. If after this exercise you still don't feel confident enough to build a kit yourself, then consider purchasing a pre-assembled unit.

The construction manual accompanying the DAC-2 is fairly easy to understand but some of the photocopied assembly photos were not reproduced well and weren't clear enough to be useful. Luckily, an exploded view of the assembled DAC-2 is provided and I relied on this view when I couldn't rely on the photos.

Not having a considerable amount of experience building electronic kits, complete assembly of the DAC-2 took me about two hours. I have no doubt that someone more experienced in the fine art of kit building could fully assemble the DAC-2 in about an hour.

Once I had completed construction of the DAC-2 and cleared my head of solder fumes, it was time to fire it up and ensure it was working. I nervously carried the DAC-2 into the listening room thinking to myself "I'm going to be awfully embarrassed if I have to phone John Stewart at The Parts Connection and tell him that I failed to get the DAC-2 working". Palms sweating, I connected the DAC-2 between my transport and preamp and powered it up. I breathed a sigh of relief when the DAC-2's green LED illuminated, indicating that the processor successfully locked to the transport's digital signal. Feeling pretty cocky at this point, I placed an HDCD-encoded disc in the transport (the excellent With Words Unspoken from The Lynne Arriale Trio on DMP Records) and hit 'play'. The front panel's red HDCD LED illuminated, and music poured from the loudspeakers. The DAC-2 was alive! Resisting the urge to jump right in and start listening to my new creation, I decided to leave the DAC-2 to burn in for a few days.

Associated Components

The DAC-2 was fed the digits from a Theta Data Basic II transport via either an XLO Type 4 or Transparent Audio HDL digital interconnect. The output of the DAC-2 was run to a Conrad Johnson Premier II preamp (an oldie but a goodie) via a Transparent Audio MusicLink interconnect. The Premier II was connected to an Aragon 2004 Mk.II amplifier by an MIT MusicChord interconnect. The 2004 drove the ProAc Studio 150s via either Audioquest Midnight Hyperlitz or Transparent Audio MusicWave Plus loudspeaker cables. All components were fed from my listening room's 15A dedicated circuits. My smallish 12' X 16' listening space was treated with Echo Busters' Bass Busters, Echo Busters and Double Busters acoustical room treatment products as well as a selection of 2" Sonex panels.

Listening
For the purposes of this review, I made use of two coaxial digital cables: my usual reference, the excellent XLO type 4, and the Transparent Audio HDL. Since neither of these cables is terminated with a BNC connector, all listening was done via the DAC-2's RCA output.

The moment I began listening to the DAC-2, I realized that this was not your typical sub-$500 DAC. It is not uncommon for a converter in this price range to have a bright tonal balance and a flat, narrow, two-dimensional soundstage. Listening to the DAC-2 was an entirely different experience. On well recorded material, the DAC-2 threw a wide, deep, soundstage, filling the space between the side walls of my listening room and extending well beyond the rear wall. There were times during my listening sessions when I was surprised by the lateral width of the soundstage rendered by the DAC-2. For example, the opening of the title track of Holly Cole's Temptation features the sound of a drum first at the extreme left of the soundstage and then at the extreme right. Lesser DACs might compress the lateral spread of these sounds into the space between the loudspeakers, but the DAC-2 surprised me with its ability to easily place the sound of these drums way outside the left and right edges of the loudspeakers. The DAC-2's excellent imaging and soundstaging abilities were also in strong evidence on the RIAS-KAMMERCHOR's recording of Brahms' Sacred Choral Music (Harmonia Mundi HMC 901591). The DAC-2 recreated a believable acoustic space inhabited by the members of the choir and was quite impressive in its ability to precisely place the vocalists in this space. The DAC-2 also exhibited a good degree of soundstage transparency on this disc, as it refused to allow voices at the front of the soundstage to obscure those further back.

Whoever coined the phrase "it's all in the details" must have had the DAC-2 in mind, as the processor's retrieval of recorded detail was exemplary. The DAC-2 had the uncanny ability to unearth subtle information from CDs that was heretofore unknown, adding the thrill of discovery to many listening sessions. In contrast to many inexpensive DACs, the DAC-2 presented this wealth of detail naturally rather than thrusting it forward at the listener in an offensive manner. The DAC-2 also scored very high on the goosebump scale as it brought the sound of Holly Cole's voice to life on the whispered "Eee Oh, Eee Oh, here we go" introduction to Take Me Home from Temptation.

One of the more impressive aspects of the DAC-2's performance was the way in which it surrounded instruments and instrumentalists with large amounts of "air", heightening the illusion that living, breathing entities were responsible for the music-making. Nowhere was this more in evidence than on Tafelmusik's superlative performance of the Bach Brandenburg Concertos (Sony Classical S2K 66289). The sound of Marten Root's transverse flute during the fifth concerto had a palpable presence, the notes exciting the acoustic space surrounding them in much the same way they do live (As a subscriber, I have the good fortune of being able to hear Tafelmusik play live several times a year.) The DAC-2 also unearthed musically significant subtleties in Root's performance that had gone unnoticed on other processors. While the DAC-2 didn't give me the urge to scalp my Tafelmusik tickets, its excellent rendering of well-recorded orchestral music kept me more than satisfied between concerts.

Another pleasant surprise of the DAC-2's performance was its tonal balance. The DAC-2 did not exhibit the bright, grating top end that is present in many inexpensive DACs. On the contrary, the DAC-2 had a smooth, extended treble which never sounded etched or bright, even on discs with a large degree of high-frequency content. Several DACs, which I've had the unenviable task of listening to, have turned the trumpet-dominated sections of Shostakovich's Symphony No.1 (Sony Classical SMK 47614) into something akin to the sound of a buzz saw. Not the DAC-2 - it sailed through Shostakovich's brass-rich scoring with aplomb, never becoming harsh or unpleasant. The reproduction of high, massed strings, long the bane of inexpensive digital processors, didn't pose any problems for the DAC-2. Well recorded violins sounded rich and sweet, rather than harsh and steely.

At the opposite end of the frequency spectrum, the DAC-2 had a satisfyingly deep bottom end, with only the deepest of deep bass notes getting short shrift. The throbbing bass lines on tracks from Holly Cole's Temptation didn't have quite the impact that they have via the Theta DS Pro Progeny, admittedly a processor with a price tag almost double that of the DAC-2's. The only minor quibble I have with the tonal balance of the DAC-2 is its apparent slight lack of energy in the lower midrange/upper bass region. On some discs, this imparted a touch of leanness to the sound of male voice and the lower registers of female voice. Mark Knopfler's voice, on Calling Elvis from the excellent Super Bit Mapped reissue of Dire Straits' On Every Street, lost some of its familiar gravelly texture, a texture that was more apparent through the DS Pro Progeny than through the DAC-2. In addition, Charlotte Neddiger's harpsichord on Tafelmusik's Bach Branderburg Concerto No. 5, had a more "tinkly" character and less authority to its lower registers than it has live or via the Theta processor. In all other respects, however, the DAC-2 proved to be formidable competition for the $995 DS Pro Progeny, in my opinion, one of the best under-$1000 processors. The DAC-2 was the Progeny's near-equal in the areas of imaging, soundstaging, and dynamics. The frequency range from the upper treble to the midrange was handled very well by both processors, the Theta managing to edge out the DAC-2 only from the lower midrange on down. One area in which the DAC-2 was the clear winner was in the area of detail retrieval, as the DAC-2 managed to mine the subtlest of detail from CDs, some of which the Theta glossed over. To be quite honest, before listening to the DAC-2, I had some reservations about comparing it to the DS Pro Progeny given the disparity in price between the two processors. The fact that the DAC-2 could not only compete with the Theta processor, but was actually able to better it in some areas, is a real testament to the skill of the engineers at Sonic Frontiers.

Summing Up
Unless you haven't already guessed it, I was quite taken with the sound of the Assemblage DAC-2. The DAC-2 is one of those rare products that has the ability to perform at a level far exceeding that which you would expect at its price point. In fact, in many areas, the DAC-2 was competitive with, and even exceeded, the performance of processors twice its price. The DAC-2's ability to convincingly render a three-dimensional soundstage, its excellent recovery and portrayal of subtle recorded detail, its lack of the digital "nasties" normally associated with inexpensive digital processors, and its innate musicality, lead me to this hearty recommendation: if you're in the market for an outboard digital processor anywhere near the DAC-2's price, you owe it to yourself to give it a serious audition. If you suddenly find yourself with a soldering iron in your hand, don't say I didn't warn you.


Associated Components

Digital: Arcam Alpha 6 CD player, Assemblage DAC-2 D/A converter, Transparent Audio HDL digital interconnect
Electronics: Arcam Alpha 9 integrated amplifier
Loudspeakers: ProAc Tablette 50
Cables: Audioquest Emerald interconnects, Monster Cable speaker wire

Anthony Kershaw Comments
The DAC-2 was graciously delivered to my door by editor, Andrew Chasin. As an upcoming deadline had to be met, only a brief audition was possible. In 10 days, I uncovered enough on this beautifully built component to add a few thoughts to Andrew's in-depth review. The DAC-2 had been assembled by Andrew, and was well broken-in by the time I started my listening sessions.

After a couple of days in my home system, I was concerned with a very bright, albeit highly detailed presentation. The component removed layers of shade on recordings, while revealing light and detail that I had not heard before. The difference was not subtle, and was quite unnerving! My ProAc Tablette 50 speakers are very revealing, and at times I found the DAC-2 too "truthful". The presentation was almost honest to a fault!

When listening to the late, great soprano Arleen Auger (Lieder - CBS Masterworks MK 42447), I heard her voice placed in a believable, if not especially deep soundstage. Arleen had a miraculously flexible instrument - a voice able to sing the most bombastic Strauss and, yet, be so very gentle in Mozart and Wolf. The DAC-2's detail was most beneficial in displaying that gentleness, and also in revealing the subtlety of her interpretations. Unfortunately, the sound lost focus when her voice reached loudly into its upper tessitura. The CBS recording is not especially clear, but the retrieval of minute detail gave me a new perspective on the performances. The slightest movement of her accompanist, Irwin Gage - whether by his body or when breathing with a phrase - was completely discernible.

My Arcam Alpha 6 one-box CD player, while not quite as detailed as the DAC-2, rendered harsher compact discs with a little more refinement. However, when changing back to the DAC-2, bass was well defined and gave my small mini-monitors the depth I sometimes crave! Telarc classical CD's (Hindemith Orchestral works Atlanta SO/Levi CD-80195 and Vaughan-Williams Symphony No 2 RPO/Previn CD-80138) were particularly wonderful when the DAC-2 was in the chain. Sadly, some of my earlier recordings on DGG, Phillips, and London, were not!

As listener, I wanted all the detail the DAC-2 revealed but without the grain or brightness. The bright sound I experienced might well be attenuated with a better matching digital cable. The Transparent HDL digital cable I was using has a fine reputation, but a more "polite" sounding cable, I feel, would be more suitable. Jitter may also have added to the unsettled presentation. I would love to hear the DAC-2 in my system utilizing different cables and an anti-jitter device. I think the results could be outstanding.

Sonic Frontiers have offered their DAC-2 at a very competitive price. Trust your ears and audition it at home. Be sure to have several digital cables on hand. With the right system match, this inexpensive component may be your doorway to digital nirvana.

Assemblage DAC-2 D/A Converter
Manufactured by The Parts Connection, A Division Of Sonic Frontiers Inc.
2790 Brighton Road, Oakville, Ontario, Canada, L6H 5T4
Phone: (905) 829-5858, Fax: (905) 829-5388
Email: tpc@sonicfrontiers.com, web: http://www.sonicfrontiers.com/TPC
Price: US$499 (kit), US$549 (fully assembled)
Source of review sample: Manufacturer loan
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