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American know-how

Cary Audio Design combines digital and analog technology in one powerful amp

Cary Audio Design is known around the world for vacuum tube components which are held in high esteem by most high-end consumers with whom I have spoken. However, many expressed their surprise when I told them about Cary's solid-state home theatre components and the Designer Series Class D amplifier under review here.


Blue LEDs, cut-crystal and aluminum fascia grace the face of Cary's digital amplifier.

This is the matching power amplifier to the C306 preamplifier, reviewed In TIE's last issue. The two units were not reviewed together because I believe that each has a place in someone's audio set-up, and not necessarily the same one. Also, I was waiting for a little more technical information from Dennis Had, master of the company he founded many years ago. While the technical stuff is important, I hold that the most consequential element of all electronics is the sound. I'll get to that after I describe the...

Like the C306 preamplifier, the A306 is a solidly made component constructed on a rigid chassis and wrapped in an aluminum enclosure. It's not an uncommon design but does look rather classy, thanks to the back-lit Cary Audio Design logo, which is made from cut crystal glass engraved with the logo and its blue LEDs glow when the amplifier is switched on.

The Sound
For my auditions, I used my own 12 year old Ethera Vitae speakers (made in Canada by Leo Lewis of Ottawa, ON) and the German-made Elac 607 X-Jets (reviewed in Vol.17, No 2). The source components were the Audio Aero Prestige SACD player (reviewed in Vol. 17, No. 3) as well as the soon-to-be-reviewed Cary CD player. All wiring was done with Nordost Valhalla cables and the Thor power distribution unit (reviewed in Vol.16, No. 4) which was connected in the system to the Exact Power line conditioner (reviewed in Vol.16, No. 3). I also used the C306 preamplifier to assure synergy.

The amp took about a week to fully burn in and settle to its ideal operating condition. This was done simultaneously with the C306 preamplifier, and when I was satisfied that everything was in good working order, I began my serious listening tests using the Elac speakers that I had just reviewed. Expecting to hear a somewhat hard, digital sound, I was taken aback after listening to just a few bars of music. First of all, there are no digital idiosyncrasies or other sonic peculiarities. In fact quite the opposite is true. Dennis Had has managed to introduce some of his signature tube sound to the A306, and that was one heck of a surprise. The Elacs sport an upgraded Heil Airmotion Transformer for the high frequencies and they reacted to the A306 as though they were connected to a good single-ended tube job - amazing! The highs were sweet, smooth and crystal clear demonstrating the amp's ability to resolve ultra high frequencies, perhaps even a touch better than some single-ended tube amps. Upper midrange (from about 2600Hz to about 5000Hz) was a bit bolder than I expect from tube gear, but exhibited impressive detail and resolution all well balanced with upper and lower frequencies. Pure midrange (from about 160Hz to 1300Hz) again blended well with the segments above and below and low and behold there were plenty of harmonics, very much as I'd expect from enticing tubes.

With my Ethera Vitaes in the system, the results were similar. Although they aren't as efficient as the Elacs, the A306 was a great match, literally extracting detail and providing precise sound stage dimensions. Also, the Etheras took on body and musical soul that few other amps have provided since I first acquired these loudspeakers.

Not to compare, but to investigate the amplifier's reaction to another preamplifier, I connected the Wyetech Labs Opal (an in-house component). As I am intimately acquainted with this preamp's voice, my auditioning session took only about fifteen minutes enough time to ascertain that the A306's sonic accomplishments are correct as described above. My test clearly showed that any good (and neutral-sounding) preamplifier will demonstrate the merits of this powerful amplifier. There is certainly synergy with the (matching) preamplifier, the C306, but don't be concerned if you already have a good one that you like.

Synopsis & Commentary
I listened to the A306/C306 (amp/preamp) combination for more than a month first to nit-pick, later just to appreciate its accomplishments. The amp's sheer power and dynamic potency controlled extreme fortissimo passages, while its conscientiously designed topology provided the sensitivity needed to reproduce subtle musical elements. My position on good audio is simple. Let me hear the instruments and voices, let me hear into the sound stage, show me front-to-back, horizontal and vertical reach. Let it be realistic and let it be involving and, finally, let it be priced in accord with quality and enjoyment. Well, the Cary Audio Design system does all that and then some. It is sure to please discriminating music lovers, even die-hard audiophiles, though I suspect that those who have a good knowledge of music will be the first to appreciate how these components convey the art form.

In Vol. 17, No. 2, we were unable to include technical details in the review of the Cary Audio Design's C306 solid state balanced preamplifier. We now have the particulars:

As with the matching A306 power amplifier, the C306 preamplifier merges digital computer technology and pure analog discrete circuitry. The C306 has four 18dB analog line gain stages two separate gain stages for each channel. One gain stage amplifies the positive phase (+180 degrees) and the other gain stage amplifies the negative phase (-180 degrees). Two stages for each channel equal the four active line circuits. All signals in the audio path are routed through Class A solid-state devices utilizing both FET inputs and low impedance push-pull bipolar output devices. To control the available gain, stepped 0.1% resistors are employed in a relay-controlled ladder attenuated circuit. This stepped individual resistor control circuit is said to provide the most signal purity.

The front panel display on the C306 is a Noritake vacuum florescent display with a blue lens. This receives and displays the critical control functions from a 32-bit Motorola CPU inside the unit. The CPU stores all user-selected information including volume level of each selected input, phase polarity and the selected balance setting for each channel. The CPU is the brain controlling the stepped attenuation system. The Motorola processor controls all functions of the preamplifier.

On the C306's analog side, there are a total of eight fully regulated power supplies dedicated to each channel's analog circuit as well as multiple power supplies for the alphanumeric, Noritake display, and dual supplies for the Motorola processor. The entire preamplifier is built from precision machined aluminum. All PC boards are multi-sided plated through G-10 glass.

Obviously, the rather complex and thoughtfully engineered C306 preamplifier provides the sonic merits referred to in our review in Vol. 17, No. 2, page 26: Nothing in this preamplifier disturbs, nothing gets in the way of the music.

A306 Solid State Balanced Amplifier

Cary Audio Design


Cary Audio Design 919.355.0010
$6,195 Cdn
$5,000 US
5 (h) 18 (w) 15 (d) 50 lbs

The Cary Audio Design A306 amplifier integrates digital computer technology and pure analog discrete circuitry. Incorporated within the A306, are a pair of ICE 1000 watt power conversion modules. These are true balanced class D switching mode amplifiers. The analog input signal entering the A306 reaches a fully balanced input stage, powered by a separately regulated, balanced 15 volt DC supply. This first input stage consists of solid- state devices utilizing FETs, N channel transistor inputs, and low impedance push-pull bipolar output devices in a Class A biased circuit. The input stage drives the amplifier modules. According to Had, this input stage accurately sets up the final analog output, tonal balance and the sonic signature.

The operation of switching Class D amplifiers generates unwanted high frequency noise which, if not harnessed, can interfere with radio and TV signals (not to mention additional problems caused by AC line noise). In the A306 great care has been taken and a lot of engineering know-how has been utilized to meet or exceed standardized EMI limits. Dual copper and aluminum shielding are employed internally to eliminate RF loops and radiation. The shields separate the dual power supplies and twin ICE power modules. AC power input conditioning is incorporated as well. The entire amplifier is built from precsion machined aluminum. All PC boards are multi-sided plated through G-10 glass.

I think this amplifier is evidence that new (and strange to me) computer-based technology can be used to accomplish the difficult task of recreating music without digital side effects; the potential downside of digital equipment.

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