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October 2003 Coda Technologies 12.0 Stereo Amplifier by Andrew Chasin
As I wrestled the newly delivered Coda 12.0 off my front porch and down the hall that leads to my listening room, I was reminded of the reasons for my longtime love-hate relationship with high-end solid-state amplifiers. While a good transistorized amplifier can get a firm grip on even the most stubborn of loudspeakers, plumb the depths of the lowest lows with seeming ease, and manage it all without altering its frequency response significantly into the fluctuating loads of most modern speakers, it can be as big as a bus, weigh a metric ton, and suck enough juice out of the power grid to brown out a small California town. And so it goes with the subject of this review, the 12.0 power amplifier from Coda Technologies, Inc., a Northern California high-end audio electronics firm and OEM supplier founded by Threshold alumni Eric Lauchli, B.D. Dale, and Lorin Peterson. The 12.0 carries on the Threshold tradition of producing amplifiers that certainly look like they can tame any speaker, but it's the quality of the sound produced that separates great solid-state amps from those with merely impressive power outputs and drive capabilities -- and gives me good reason to continue lugging such heavy beasts into my listening room. Description At a generous 19"W x 7"H x 19"D in size and tipping the scales at just under 90 pounds, the Coda 12.0 is an absolute bear to move around. It literally took me a half hour to figure out how to lift it out of its shipping box without slipping a disc. Placing the 12.0 onto the bottom shelf of the Finite Elemente Pagode Master Reference rack without seriously damaging the rack’s brushed-metal uprights or Canadian-maple shelves was another experience I’d rather not repeat -- at least not alone. One quick look at the $6550 USD 12.0 should be enough to tell you that this is not your run-of-the-mill power amplifier. Besides the sheer bulk and weight of the product, the machining and finish of its metalwork, quality of its connector complement, and industrial design are all first-rate. Unlike those on other amplifiers I’ve seen, the massive heatsinks that run the entire depth of the 12.0’s chassis are nicely finished and won’t slice your hand like jagged pieces of glass. And lest you think that the heatsinks on the 12.0 are just there to make the amplifier look serious, they’re necessary to dissipate the heat produced by the amplifier’s 28 output devices per channel. The fact that the heatsinks never got too hot to the touch, even after the amplifier was playing music for extended periods at average volume, leads me to believe that they were working as Coda had intended. The Ferrari exterior of the 12.0 doesn’t camouflage VW innards. The circuit boards used are all fiberglass epoxy with gold plating over tin/nickel. According to Coda, "the gold layer will not corrode and the tin/nickel barrier prevents the gold from migrating to the lower copper layer and detracting from its appearance." You have to admire a company that cares about the appearance of the inside of its products. Coda has eschewed the use of ICs in the 12.0’s signal path and uses only metal-film resistors throughout. Signal wire is used sparingly, but what is there is 141-strand, 18-gauge silver and silver-plated-copper wire insulated with silicone. As far as power goes, the Coda 12.0 produces 100Wpc into an 8-ohm load and doubles that into 4 ohms. For those with a penchant for more power, the 12.0 can be bridged for mono operation, at which point it becomes capable of generating 400W into 8 ohms and 800W into 4 (I sense that Maggie owners around the globe are starting to drool). The 12.0’s power supply is beefy and comprised of two 2000VA toroidal transformers, one per channel for true dual-mono operation, with a total of 200,000 uF of filter capacitance. Operation is class A with the use of a "precision bias" circuit to ensure that the inevitable transition out of pure-class-A operation under certain circumstances (very low load impedance, for example) is not accompanied by an increase in distortion (more details on precision bias can be found at Coda’s website). The front faceplate of the 12.0 is comprised of a gently rounded chunk of anodized aluminum containing two vertical, contoured elliptical cutouts (presumably to be used as carrying handles, although more conventional handles are attached to the amplifier’s back panel). Toward the bottom center of the faceplate is a small horizontal elliptical section that houses two pushbuttons: the Bias button (which may have been more intuitively named Standby) brings the amplifier out of standby mode and un-mutes the output, and the Input Selector button switches between balanced and single-ended inputs (these functions can also be controlled via an available remote control, omitted from the review sample). Three LEDs arranged horizontally to the right of the pushbuttons indicate that the left channel is powered, the right channel is powered and the main power is on, respectively. The latter button illuminates red when the single-ended inputs are in use and yellow when the balanced inputs are in use.
Review system I listened to the Coda amp in the context of my usual review system, consisting of a VPI Aries turntable/VPI Synchronous Drive System/Graham 2.0 tonearm/Transfiguration Spirit phono cartridge analog setup, a Hovland HP-100 preamplifier with MC step-up transformer, and a pair of ProAc Response One SC loudspeakers. The One SCs sit atop Target R4 stands filled with sand. All components are housed in the previously mentioned Finite Element Pagode Master Reference rack. Cables used included the Hovland Music Groove 2 phono interconnect, and Harmonic Technology Pro-Silway Mk.II interconnects, Pro-9 Plus speaker cables, and Pro-AC 11 power cords. Amplifiers on hand for comparison covered all bases. They were a solid-state Simaudio Moon W-5 (my usual reference and a SoundStage! Reviewers' Choice), a hybrid Blue Circle BC28 (review forthcoming), and a pair of tubed Audio Electronic Supply SixPac mono amplifiers (the deal of the century in all-tube monoblocks). Listening Let me start by saying that the Coda 12.0 is one amplifier you don’t want to hear cold. Before it’s adequately warmed up (give it at least an hour or two after power-on), the 12.0 is sterile, lifeless, and generally not much fun to be around. Even post warm-up, you’d never really mistake the 12.0 for anything other than a solid-state amplifier, which is, I’m sure, exactly as the Coda engineers intended. I have to admit that, at least initially, I had some real reservations about the sound of the Coda 12.0. It didn’t sound particularly musical or involving, was a bit sinewy in the treble, and, perhaps most surprisingly, didn’t go particularly low in the bass. I can’t say for sure if, over time, it was the 12.0 that broke in or whether I simply adjusted to its presentation, but a few weeks into the review process I started to understand several attributes of the 12.0’s sound. On orchestral material, for example, such as the Concertgebouw’s lovely performance of Mahler’s Fourth Symphony [London CS6217], the 12.0 sounded effortless and explosive, with enormous amounts of dynamic headroom. On jazz and rock recordings, the 12.0’s rendering of such things as rim shots, snare-drum whacks and other percussive effects absolutely startled with their impact and speed. Although the ProAc Response One SCs aren’t exactly the last word in macrodynamics (there’s only so much you can get out of a small box with commensurately small drivers), the 12.0 seemed to wring more out of them dynamically than the more powerful Simaudio W-5. Along with its explosive dynamics, the 12.0 had a big, open sound and painted a realistic picture of the recording space. The soundstage on the aforementioned Mahler Fourth was voluminous when heard through the 12.0, with wall-to-wall width and acres of depth. Furthermore, images were placed within this soundstage with meticulous precision. Post break-in, the low-end reproduction of the 12.0 also truly came into its own. While the One SCs fall well short of full-range reproduction (their specified -3dB point is 38Hz), the power of the bowed double bass on the Mahler Fourth and the realistic "thump" of Scott LaFaro’s plucked upright bass on Bill Evans’ Waltz for Debby [Riverside/Analogue Productions APJ 009] had me staring at the One SC’s 5" woofers in disbelief. Through the midrange, the 12.0 sounded clean, tidy, and had plenty of detail, although it lacked the warmth and body of the hybrid tube/solid-state Blue Circle BC28 and the AES SixPacs. The sound of Norah Jones’ voice on her blockbuster debut Come Away with Me [Blue Note/Classic Records JP5004] was smooth and silky, yet somewhat detached, lean, and less believably human through the 12.0 than it was through either the BC28 or SixPacs. Although the 12.0 realistically rendered the sultry sound of Patricia Barber’s voice on "Touch of Trash" from Modern Cool [Premonition Records PREM-741-1], its golden, husky tone was less in evidence. Chalk it up to good ol’ tube euphony, but while the 12.0’s midrange performance was on par with other good transistor amplifiers, it couldn’t conjure up the same meat-on-bones quality heard through the tube-based SixPac amplifiers or the hybrid BC28. I’ve already touched on the 12.0’s ability to sound effortless and open, and to accurately convey the scale of a recording venue, but it was one of the Coda’s strong suits and was a real boon on large-scale symphonic works. The fortissimo passages in Mahler’s Fourth, for example, were reproduced without the sense that the 12.0 was breaking even the lightest sweat -- the music simply swelled in volume as it does in a live, unamplified setting. Now, I’m not delusional enough to expect a small speaker like the One SC to play huge orchestral works in an average-sized listening room without some sense of miniaturization and dynamic constraint, but, when driven by the 12.0, I’d be damned if the little ProAcs didn’t sound like they’d grown a couple of inches and put on a few pounds around the mid (and bass) section. Although I came to admire the neutrality of the 12.0’s midrange and was impressed by the amp's heft and extension in the bass, I never did manage to completely warm up to its cool treble performance. Even on good, all-analog recordings, massed high violins sounded relatively thin and wiry -- in stark contrast to the woody, resiny sound heard through the BC28 and SixPacs. While the 12.0 rendered Paul Motian’s cymbals on Waltz for Debby with plenty of shimmery detail, they lacked the burnished undertones heard with the other amplifiers used for comparison. Ditto the sound of trumpets and other brass instruments played in their high registers, all of which exhibited a bit too much bite. I can’t discount the possibility that my impressions of the 12.0’s top end might have been exacerbated by my choice of loudspeaker -- the One SC’s revealing tweeter coupled with its lack of full-range bass response may not have been in the 12.0’s favor. That said, when driving the same loudspeaker, the top-end of the solid-state Simaudio W-5 sounded more refined and better integrated with the rest of the frequency spectrum. Comparisons and further listening impressions The $6550 Coda 12.0 was the most expensive of the four amplifiers I had on hand during the course of this review, the others being the $4995 Simaudio Moon W-5, the $3995 Blue Circle BC28, and the $2400-per-pair Cary Audio/AES SixPacs monoblocks. In terms of build quality, the Coda 12.0 is in the same league as the W-5 and other relatively pricey amplifiers -- parts quality appears very high, its tank-like exterior and excellent fit'n'finish exude quality, and its operation was flawless. In the watt-per-dollar category (important to some), the 190Wpc W-5 comes out on top, although the Coda 12.0 sounded far more powerful than its 100Wpc rating would indicate. While I haven’t tried it, I would expect excellent results when partnering the 12.0 with traditionally difficult speaker loads, such as those presented by the hybrid electrostatics from Innersound and Martin Logan and the planar-magnetic/ribbon hybrids from Magnepan. Although the 12.0 was blessed with superb bass extension and had a big, open sound that was intoxicating on large-scale symphonic works, its less-hefty midrange and thin treble were bettered by the more neutral and refined Simaudio W-5. While perhaps slightly less revealing of high-frequency detail, the W-5’s top end was better integrated with the rest of the frequency spectrum and never called undue attention to itself. Both the far less expensive BC28 and AES SixPacs bettered the 12.0 in the areas of midrange sweetness, treble purity, and that elusive sense of musical "rightness." Female vocals through the tubed amplifiers were nothing short of seductive, with a warmth and naturalness that few solid-state amps can match. To my ears, the finely filigreed treble of the BC28 and SixPacs (the latter driving the One SCs from their 4-ohm taps) was not a result of premature rolloff or some tube trickery -- everything I expected to hear from familiar recordings was there, just in better harmony with the rest of the sonic landscape. Not too surprisingly, the 12.0 was all over the BC28 and SixPacs, and even edged out the W-5, in terms of bass extension and sheer dynamic impact, although the "quality" of the bass reproduction was comparably high through the tubed amplifiers. While the 12.0’s superior bass power and extension were obvious, I can’t say I felt I was missing much in purely musical terms when I swapped the Coda amp out in favor of the BC28 or SixPacs. Conclusions While I’ve dissected the 12.0 into typical audiophile terms (bass extension, transparency, soundstaging, and the like) in an attempt to communicate its strengths and weaknesses, such things on their own tell only part of the story. Ideally, these discrete attributes of an audio product will, by some miracle of science, gel together to form a musical conduit through which one's favorite recordings come to life. Unfortunately, I never had the sense that this really ever happened with the Coda 12.0. While I did admire the 12.0’s many traditional audiophile strengths, I never felt I could completely relax and immerse myself in the listening experience when the amp was in my system. Familiar recordings took on a "hi-fi" sound, with a top, middle, and bottom but little cohesion. I couldn’t help but feel I was listening to the hardware rather than the music. Given the 12.0’s low-end prowess and driveability, it may very well be a great choice as the bass amplifier in a biamped configuration -- say, a powerful tube amp with delicate highs and voluptuous mids on top and the 12.0’s kick-ass power and bass down below. That could be something to hear. On its own, however, I think the 12.0 is somewhat less than the sum of its sonic parts. I did come to appreciate certain things about the 12.0, but I never quite adjusted to its cool treble and midrange leanness. In these regards, it is bettered sonically by some less pricey competition. ...Andrew Chasin
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Around back are high-quality
gold-plated RCA and Neutrik XLR connectors for single-ended and balanced operation, a
heavy-duty rocker-style power switch so that the amplifier can be powered down when not in
use for extended periods, and an IEC receptacle to facilitate the use of an after-market
power cord. That’s the good news. The bad news is that the speaker binding posts
(four per channel in support of biwiring) are an ergonomic nightmare. Apparently CE
approved, these posts "feature" vertical slots for attachment to
spade-terminated cables, like the Harmonic Technology Pro-9 Plus cables I use in my review
system. Fortunately, the spades on the Pro-9 Plus just happen to fit in the slots provided
(you may not be so lucky), but with the amplifier installed in my Pagode rack, and the
amp's back panel facing the front wall of my listening room, vertically aligning the
spades of the relatively stiff Pro-9 Plus cables with the slots on the binding posts was a
major pain -- especially considering the limited space I had at my disposal between the
back of the rack and the wall. The Coda R&D team has obviously put a lot of effort
into the design of the 12.0, but the inclusion of these binding posts on an otherwise
well-thought-out product was a major blunder. Enough said.