Conrad -Johnson CA200 Control Amplifier

Equipment report
Integrated amplifiers
Conrad Johnson CA200
Conrad -Johnson CA200 Control Amplifier

I owe a debt of gratitude to the conradjohnson CA200 control amplifier and a saxophone. In a single moment they crystallized in my mind a conclusion that I arrived at during last year’s Class D amp survey. There I opined (as did some of my colleagues) that the sonic picture created in the treble range by Class D amps seemed less than complete, lacking in harmonic complexity and dynamic energy.

The sax in question is featured in the title song of Jennifer Warnes’ Famous Blue Raincoat: The Songs of Leonard Cohen [Cypress] Rather than reproducing the instrument with its plaintive sound intact, the Class D digital amps made it sound, well…odd. Still a sax, yes, but one that had morphed into something synthesized, one-dimensional, and airless. As luck would have it I decided to bounce these impressions off the then recently delivered CA200 control amplifier. This 185Wpc, zero-feedback design, with a bipolar transistor output stage, reintegrated the sax and all its gritty emotion into the larger spatial environment where it was recorded. Throughout the Class D survey, the CA200 control amplifier stood in as one of the most revealing sounding boards I could have asked for.

Following this experience I chatted up conrad-johnson vice-president Lew Johnson for details about the CA200. He emphasized that the CA200 is not an integrated amplifier per se, because that implies the presence of a linestage preamplifier and there is no linestage in the CA200. The audio circuit comprises a single voltage gainstage, followed by a high-current buffer/output stage. “It’s exactly the same circuit found in the Premier 350, scaled down to roughly one-half scale (185 watts per channel), as dictated by the compact chassis size,” Johnson said. “This circuit uses our autolinear gain circuit that is designed for zero distortion (theoretical) with zero feedback—and in fact, as is the case with the Premier 350 amp, there is no loop feedback in the CA200.” Finally, the bipolar transistor output stage achieves a high damping factor without loop feedback.

In essence, the CA200 is a highgain amplifier harnessed to a steppedattenuator level control and inputselector switches. As Johnson would be the first to point out, less circuitry and the elimination of a set of interconnects give amplifiers of this ilk an advantage, but only if other elements have been equally well-executed. Certainly, parts-quality is first-rate: Vishay metal-foil resistors (including all elements of the discrete stepped-attenuator level control), CJD polystyrene capacitors, and the same input and output connectors found on CJ’s flagship products.

The sonic character of the CA200 is marked by a golden sweetness and a hint of tube-like warmth that are best appreciated with acoustic instruments and voices. A great example is Mark O’Connor’s tasteful fiddle accompaniment of James Taylor’s vocal during “Hard Times Come Again No More” [Appalachian Journey, Sony]. There’s a red richness to the midrange of both of these instruments—a bit of darkness, but also high transparency. I could hear the CA200’s slightly forgiving character on transient cues, but also a closedfisted authority in the lower octaves that is equal parts timbral realism and pitch extension and control—traits that often fail to be realized at the same time in many one-box amplifiers. The CJ’s dynamic reserves are considerable, but it’s at its most expressive with complex harmonic interplay—the kind of challenges that the disparate voices of a symphony orchestra routinely provide. Even on a well-worn recording like Bryn Terfel’s “Il Mio Cuore Va” [Sings Favourites, DG], the brass and wind sections were no longer a blur of activity on a fuzzy soundstage; they expressed varying degrees of dynamics and loudness, smoothly layered into the overall orchestral image. Although it reproduces studio-mounted pop with élan, the CA200 somehow sounds as if it’s slumming a bit—as if these compressed and contrived creations hardly present a meaningful challenge. Like the best amplifiers, the CJ is profoundly quiet, which lets it express gossamer-fine microdynamics, allowing even Evgeny Kissin’s most delicate touch on the Steinway to contrast with a note sounded a hare’s breath less pianissimo [The Lark, RCA].

Don’t think for a minute that the CA200 turns up its nose at rock, however. It might have been to finishing school, but the CA200 will play dirty. Just crank up the volume on Lucinda Williams’ searing “Changed the Locks” and hear the sweat and drive of the churning rhythm section and scorching Telecaster bearing down on Williams’ push-me/pull-me tale of the love obsessed. As with classical material, spatial details prevail and Williams’ vocal is a few feet more distant, back in the rhythm section mix. While an amp like the Plinius 9200 is almost down her throat, presenting her voice with gravelly roughness, the CA200 reproduces the same vocal with finer grit. Which is more correct? Hard to say, except that the 9200 probably captures more of the raw, inyour- face emotion of the performance.