That effortless sense of control is a big part of what drew me to solid-state muscle amps in the first place. Now don't get me wrong - I just love the humanity and musicality of tube amplifiers. Nor am I making any grand proclamations as to the relative merits of one style of amplification over another. But based on my own listening tastes (and the kinds of loudspeakers I have had access to), I've always liked to employ a tubed preamp (to confer sweetness and a relaxed, juicy sense of midrange layering and detail) in tandem with a high-powered solid-state amp (for the kind of speed, dynamic veracity, clarity and depth of field I enjoy).

Perhaps we are getting a little ahead of ourselves at this point in our commentary? Regardless, I've simply got to tell you right now that running my system with a VTL 5.5 and the McCormack DNA-500 over the past several months has made me as happy as a clam - well, a fairly portly, sarcastic clam (but you get the idea). It has also confirmed my sense of impatience with doctrinaire audiophiles types who wax dismissive when discussing solid-state, never mind how the best tube and transistor designs over the past decade have come to cross-pollinate each other. Tube designs now display a greater degree of accuracy and control while solid-stare gear evinces new levels of warmth and (there's that word again)... humanity. This has certainly been my experience dating back to the Stereophile days of evaluating amplifier designs by such respected makers as YBA, Sim Audio, Musical Fidelity and Linn - solid senders all. Speaking specifically of the McCormack DNA-500, not only does it have superb bass extension and control and a lovely sense of midrange layering and liquidity, but it also has an exceptionally smooth, detailed top end. I suspect that when audiophiles reflexively buy into received wisdom which holds that solid-state amps may safely be dismissed as bright, edgy, brittle and cold, perhaps they're still in remission from Julian Hirsch's test bench that proclaimed all well-designed transistor amplifiers to sound identical but perhaps not very good some 15-20 years ago.

"I'm sure you are right," McCormack concurs, "but I would have to say that even today, I listen to a lot of solid-state gear that falls short of the musical values I hold dear -- that whole sense of musicality, the pace of the rhythm, the involve-ment and emotional connection -- which tube equipment does naturally well whereas solid-state tends to do transparency and neutrality more naturally. Tube gear often has a lot of personality and while that can lead to tonal colorations and other problems, it still achieves this profound sense of musicality and a deep emotional connection. The trick then becomes to combine all of those elements."

Well, as I'm wont to say, the Lord do giveth and the Lord taketh away. While tube amps do indeed possess midrange magic, they often add
an audible artifact to the music. Still, one man's coloration is very often another man's musicality. "I would agree," McCormack continues, "but what I am trying to do with my amp designs is to create something more like what I perceive to be a window into the performance. I'm trying to downplay the personality of the amp so you can define that quality through other means -- such as with the kind of preamp or speakers that balance out the system -- where you're not forced to have the amp impose a personality of its own; at least in so far as I am able to take that out of the equation. I want the amp to be like a chameleon, to disappear into the system and just reproduce whatever it is fed."

"If we talk about watts into a fixed load, that's a product of applied voltage to that load and the current becomes a fixed equivalent value. If there are perceived differences in how an amp plays out with a given set of speakers in the domain of power, that's a more subjective thing. It may have something to do with how the power supplies are designed. Watts are always watts when you are on a test bench driving a resistive load. The real test comes when you start driving speakers. They are a complex reactive load which does not behave like resistors. Now you start getting into inductive and capacitive reactance. The question then becomes how well your amplifier circuit deals with reactive loads. Anything that's purely resistive or approaches pure resistance like Vandersteens or Magnaplanars is relatively easy to drive. Just about any amplifier will do its best into those speakers. But when you start getting into some of the big Thiels, Aerials, B&Ws or Dynaudios that become very strongly reactive, now you're going to observe significant qualitative differences in how amplifiers actually behave and how relaxed and dynamic (or compressed and flat) they sound into such challenging loads."

"I've found that an amplifier featuring a bipolar output stage and a massive high-current power supply seems related to that sense of relaxed authority I like so much. And I guess that accounts for the bridged nature of my system as well. To my ears, the sense of control I can achieve in this way is clearly superior. And while these advantages hold true throughout the frequency spectrum, it seems to be most obvious and demonstrable down in the bass register where the literal degree of amplifier control over the speakers is most profoundly felt.

The term DNA stands for Distributed Node Amplifier, a technique I pioneered with the DNA-1 back in 1989. It involves separating the power supply capacitors into multiple small, high-performance caps and locating them as close as physically possible to the output transistors. This provides energy storage that is directly adjacent to the output devices for the lowest possible power supply impedance when the music demands fast, transient current peaks. This architecture contributes to the sense of clarity and dynamic expression for which the DNA amplifiers have become known. In the DNA-500, I've taken this idea one step further, by staging the power supply capacitors such that each channel has 6 x 12,000uFd for a total 72,000uFd of local high-quality capacitors adjacent to the high-speed, soft-recovery rectifier diode bridge for primary smoothing and main energy storage, while each of the 12 output transistor per channel benefits from its own close-proximity 1000uFd cap chosen for best sonics."

"Another key to the DNA-500's performance is the input phase-splitter," McCormack adds. "I've chosen a Jensen trans-former for this role and feel it provides unmatched performance. The DNA-500 provides both balanced and unbalanced inputs and my input circuit design processes both inputs through the Jensen transformer. This transformer-coupling blocks DC and RFI (radio frequency interference) and provides the best-possible common-mode noise rejection (CMRR approaching -130dB). It also allows for a simplified input stage topology for better sonics. Common-mode noise rejection is normally associated only with balanced inputs but my input circuit provides substantial noise rejection also for unbalanced signals (this is dependent on the type of interconnect cable used but works very well with twisted-pair or equivalent cable designs)."

"In addition, we employ a very sophisticated complement of electronics throughout the DNA-500. This includes Vishay and Caddock resistors, Nichicon electrolytic capacitors, Polystyrene and Polypropylene film capacitors, the Jensen signal transformers, IR and Harris soft-recovery diodes, a massive EI core power transformer and Van den Hul carbon/metal-hybrid output wiring. The DNA-500 also incorporates five of the Soft Shoes damping feet I designed to enhance the performance of my equipment and a 20-amp Hubble plug instead of the more common 15-amp IEC inlet. Why? In my experience, it is not only provides a more stable connection but also sounds a lot better."

Sound And Fury Signifying...
Right out of the box, the DNA-500 sounded every bit as good as my long-time reference, the hybrid Musical Fidelity Nu-Vista 300 (which as the name implies, outputs an honest 300wpc into 8 ohms). After several weeks of extended burn-in, the DNA-500 seemed to become ever more powerful and relaxed, with a yet greater sense of ease, more midrange depth and detailing and an even wider dynamic range.

For someone who often listens at fairly fervent volume levels, I noticed that as the amp settled in, I was turning my preamp levels lower and lower. You see, it's not so much that I am addicted to sheer volume - I'm always trying to achieve the
fullness and presence of a live music experience. I've found that with most amps, there is a point at which I tend to push things until they begin to sound full and exhibit a palpable sense of presence and immediacy. [This is also a function of using low-efficiency, high-reactance speakers which require higher input signal to "lift the veils" - Ed.]

So imagine my surprise when I found myself gradually employing less and less sheer gain. And while I have happily operated both the 8-ohm/88dB Joseph Audio RM25si Signature Mk2s and the 4-ohm/90dB Dynaudio Special 25s with a modestly powered Linn Classik, a Sim Audio i-5 integrated and a tubed Mesa Tigris integrated (running at 28 watts in the 2/3 pentode-1/3 triode mode), both of these loudspeakers readily responded to a healthy dose of current to reach their full dynamic potential. With these superb loudspeaker systems, the DNA-500 delivered the kind vivid dynamic immediacy I crave and did so in such an effortless, graceful manner and with such relaxed authority, that I never felt as though I was pushing the system too hard or was venturing anywhere near the point of clipping.

Let's return to that theme anon. But first, given prevailing attitudes about the audio verity of tubed power amps and my own sundry experiences thereof, I thought it prudent to concentrate on the McCormack's depiction of the critical midrange frequencies. This is an area where tube amps traditionally enjoy a natural superiority in the estimation of audiophiles. I am certainly not here to dispute that, only to point out that with a well engi-neered, carefully thought-out transistor amp, the
depiction of the midrange needn't be cool, detached and uninvolving. Nor must a solid-state amp play into the rest of the deeply held and often misleading clichés in terms of overall sonic character or lack thereof.

Given the astonishing resolution and dimensional veracity of the Linn 1.1 Unidisk, I thought it prudent in the final listening phase to lean a bit more heavily on vinyl sources than I normally might, just so I wasn't attributing more than its fair share of sonic credit to the McCormack. I needn't have been so timid in trusting the evidence of my ears. The McCormack imbued all source materials I tossed at it from my humble analog front end with the same superb degree of weight, scale, speed, detail, clarity, resolution and dimensionality I enjoyed with the Olympian Unidisk player.

Where shall we start? Well, first, let's address the notion that the perspective of solid-state amps tends to be on the bright side. To this end, I tossed on one of my favorite Jazz performances, that of Ginger Baker and the Denver DJQ2O (Denver Jazz Quintet to Octet) on their Atlantic recording Coward Of The County. Given that these sessions were recorded directly to ½" analog tape, Coward Of The County has a palpable dynamic immediacy and visceral presence that accurately conveys the excitement these musicians felt as drummer Baker pushed them to their limits and as they in turn inspired him to reach for levels of collective intensity and joy he's enjoyed all too infrequently since the halcyon days of Cream. However, this recording was made at a tape speed of 30IPS which is traditionally employed to bring out the complex overtones and pristine intimacy of string instruments (much as Windham Hill did with their popular solo acoustic guitar recordings). 15IPS is generally better suited to reproducing the low-end slam of drums and bass. As a result, the recording is rather on the bright size, a tendency that was only exacerbated by too much gain and too little corrective EQ in the mastering process - which basically means you have to back off on the gain during playback. [Chip & Ginger in Verona/Italy to left.]