Listening #131

Whenever I'm moved by an artist whose work I've never before heard or seen, my first impulse is to wonder: What else has this person done while I slumbered in ignorance?

The same applies to those audio designers whose craft has approached the level of art. The products of Ken Shindo, Tim de Paravicini, Jean Constant Verdier, J.C. Morrison, Junji Kimura, Don Garber, Denis Morecroft, and a handful of others have all elicited that response—yet none more than the late Hiroyasu Kondo. His Audio Note Ongaku amplifier of 1989 woke the world to a number of possibilities: that a successful commercial amplifier could be designed to operate in single-ended mode; that it could be designed around new-old-stock (NOS) power tubes (footnote 1); that it could provide less than 30Wpc of output power; that it could forgo printed-circuit boards in favor of point-to-point wiring; that it could contain not a single solid-state component; that it could be shockingly expensive.

I didn't hear an original Ongaku until around 1996, by which time the burgeoning single-ended-triode movement had adopted its designer as an unofficial firebrand: understandable, I suppose, but to restrict the Kondo legacy to just one output-circuit variation is to miss the point. For one thing, as revealed in a 1996 interview with former Stereophile contributor Jonathan Scull, Kondo-san also designed and built amplifiers using push-pull architecture, the merits of which, "when properly executed," he endorsed. For another, it seems that, more than any matter of circuit architecture, Kondo's greater concern was to design and manufacture every component part used in his products, down to making his own capacitors by hand, and creating a custom die for the extrusion of his silver wiring.

Those things were brought to mind by two relatively new products in the Kondo line: the Overture integrated amplifier ($33,900) and the GE-1 phono preamplifier ($12,900). Both were designed by Katsura Hirokawa and tuned by Ashizawa Masaki, the latter of whom joined the company in 1990, as Kondo-san's apprentice. Masaki-san is now the CEO of Kondo Audio Note Co., Ltd. in Japan (footnote 2), which remains in the hands of the founder's family. Owing to a change in US distribution, from the former distributor to New York City–based Rhapsody Music & Cinema, the Overture and GE-1 recently spent two months in my system: the first new Kondo products I've experienced at home in a number of years (footnote 3).

Made of stone-ah
Although it appears modestly sized in the photos on Kondo's website—as would virtually anything when viewed alongside the 75-lb Ongaku—the Overture integrated amplifier is something of a beast in person, measuring nearly 17" deep and weighing over 45 lbs: almost too much for even the top shelf of my Box Furniture equipment rack. The sturdy, meticulously crafted chassis, made from a combination of steel, brass, and aluminum pieces, is described by Ashizawa Masaki as "expensive and complicated, but very useful for sound tuning." Also contributing to the Overture's heft are its custom-wound Tango power transformer and output transformers—among the amplifier's relatively few parts that aren't made in-house.

1113listen.overture.jpg

After removing the Overture's top plate—and admiring the all-too-rare beauty of a five-figure audio product whose casework is so well engineered that all of the construction bolts and their threaded holes line up perfectly, and whose chassis does not flex with the weight of the parts within—I couldn't help being impressed with the appearance of the handmade silver-foil capacitors used in the signal path. Each is marked with its precise value, along with the name of the technician who made it and the date of its manufacture. The choke coils and the smaller transformers are also the company's own, as are all of the internal hookup wires. The tantalum resistors, although made at another facility (using Kondo's solid silver wire as leads), are a proprietary Kondo design, and are individually measured and sorted in-house for consistency. The silver input and output connectors, too, are Kondo's own design, made to their specifications.

Adjacent to the audio-signal circuitry, extending beyond the range of the tubes themselves, is another Kondo signature: a ground plane made from pure, solid copper. The present-day manufacturer of Kondo products extols the use of solid copper for its RFI resistance and good mechanical grounding properties; Hiroyasu Kondo, in his writings and conversations, suggested that the electrical current meant to mimic music sounds best when comprising electrons drawn from copper and silver. (Again I'm reminded of the dictum that audio devices tend to sound like the materials from which they're made—something I learned from writer Herb Reichert, and that Herb learned while working for Audio Note.)

1113listen.overins.jpg

The Overture's volume potentiometer could be regarded as an off-the-shelf part, assuming the shelf in question is sturdier than average. The Alps HQPro, which is completely encased in a precision-machined brass housing, would be too large to fit inside some of the high-end preamps I've owned. (Although the Japanese Alps company appears to aim the HQPro series at their home market only, I found the website of a Polish electronics distributor that offers the Overture's 100k ohm version for the equivalent of $550.) But the Overture's Russian-made tubes—two EL34 output pentodes, one 6072, and one 12BH7 per channel—really are off the shelf, having been supplied by Electro-Harmonix, the company that began life making such guitar pedals as the Big Muff „ and Small Stone. These tubes may seem less tony than the rare, NOS tubes supplied by other amplifier makers, but I can vouch for at least the Electro-Harmonix 6072 dual-triodes used as the Overture's input tubes, which sound uniquely clear and noise-free in the input sections of my Shindo Corton-Charlemagne monoblocks (footnote 4).

Speaking of the Corton-Charlemagne, the Kondo Overture shares with that amp its use of a class-A, Ultralinear, push-pull output circuit with minimal (3dB) global feedback, executed by Kondo with split-primary output transformers custom-wound by Tango. According to Ashizawa Masaki, an Ultralinear circuit was chosen in order to ensure "reasonable output power, [while] at the same time we have to reproduce smooth tonal character, like a triode." A fixed-bias circuit was chosen to avoid the need for high-power-handling cathode resistors: "Good-sounding ones are rare," according to Masaki-san, who also points to Kondo's proprietary Constant-Current Bias (CCB) circuit, wherein the music signal is spared from passing through the circuitry used for setting bias voltage. Maintaining an appropriate relationship between the music signal and the circuitry for the amplifier's operating voltages is also stressed throughout the Overture's power supply, where Masaki-san says that circuit-layout techniques are critical.

The 32Wpc Overture isn't big on creature comforts, lacking a balance control, a mono switch, and, as one might guess from its pairing with the Kondo GE-1, a phono stage. But it does offer four pairs of line-level inputs—selectable by means of a rotary switch with an unusually solid feel—and a choice of 4 or 8 ohm output sockets. Notably, the Overture also offers freedom from that most needless of all extra-cost accessories, the remote control. The Overture comes standard with the company's ACz Avocado silver AC cord, which sells separately for $2450.

With regard to the Kondo Overture's build quality, I can say only that I've never seen a more meticulously constructed amplifier, be it tubed or solid-state, from any manufacturer. The attention to detail and the sheer level of craftsmanship displayed in the Overture are nothing less than staggering.

The same construction quality, as well as the same silver wiring, handmade capacitors, bespoke resistors, copper ground plane, and tuned, multi-metal chassis, are seen in the Kondo GE-1, a moving-magnet (34dB of gain) phono preamplifier with separate, switchable input pairs for two phono pickups. The GE-1 uses three of the aforementioned Electro-Harmonix 6072 dual-triode tubes, which provide a two-stage, zero-feedback gain circuit and a cathode-follower final stage for low output impedance. At the other end of the GE-1, an input-impedance selector switch—with choices of 20, 50, and 100k ohms—offers the user a non–signal-degrading means of tailoring response in the face of turntable rumble or other system anomalies. The power supply of the GE-1 is built around an original Kondo cut-core transformer and a 6X4 rectifier tube, with a solid-state (TO3 transistor–based) supply for the heater circuits. The stock AC cord is Kondo's ACc copper, which sells separately for $1150/1.75m.



Footnote 1: Today, new samples of the VT4C/211 output triode are available from China.

Footnote 2: There is inevitable confusion between two companies sharing the same name. Audio Note in Japan, whose Kondo Overture and GE-1 are reviewed in this issue's "Listening," is referred to as Kondo Audio Note; Audio Note in the UK, which is no longer connected with the Japanese company, is run by Peter Qvortrup.—Ed.

Footnote 3: Kondo Audio Note Co. Ltd., 242 Shimohirama Saiwai Kawasaki, Kanagawa 212-0053, Japan. Tel: (81) 44-520-3150. Fax: (81) 44-555-8350. Web: www.audionote.co.jp. US distributor: Rhapsody Music & Cinema, 27 W. 24th Street, Suite 506, New York, NY 10010. Tel: (212) 229-1842. Web: www.rhapsodycinema.com.

Footnote 4: The E-H 6072 is available in matched pairs from a number of sources; I bought mine from McShane Design, of Orland Park, Illinois.

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COMMENTS
ken mac's picture

. . .of an excellent product. Just as I always enjoy the level of detail and musical wordflow in Art's reviews, when I heard the Kondo system at the last NY Audio show it was one of a handful of musical listening ephanies I've ever experienced. You're spot on re Kondo's different tonal approach when placed next to Shindo, both manufacturer's wares equally beautiful in their release of the notes.      

popluhv's picture

Love the list this month!

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