Common sense still suggested that the XLR inputs would be convenience items given the presumably single-ended power stage. Yet there are not only three gain stages and the need for XLR shorting plugs when using the RCA alternates. There's a deeper course correction. The bare specs suggest that we're not dealing with a paralleled single-ended scheme but just one lone output device. That makes the 800-watt 2Ω rating—which isn't in the leaflet but was subsequently given by Kiuchi-—nearly monstrous. So the KAP-777 is a stout low-impedance doubler. Tech talk calls that load invariant though a practical proviso remains. Stay above 1.5Ω. What's more, this is a 5Hz-100kHz wide-bandwidth circuit housed in a 33kg casing of 20x43x46cm HxWxD dimensions. As its muscular specs underscore, this is a properly big amplifier which should drive anything except for that rare design aberration of a speaker which should never have gotten made in the first place. Final specs are an S/N ratio of better than 100dB; 30dB of voltage gain; and input impedance/sensitivity of 40kΩ/0.77V. Kiuchi-San would also want you to know that it uses their own Harmonix hookup wiring, tuning feet and binding posts. The Harmonix brand name in fact accompanies a whole slew of exotic resonance-control tuning devices to remind us.


To use a modern word, Kiuchi-San's special expertise and focus are tweaking. He surrounds himself with experts in various design disciplines for what he calls high-tech fusion. Yet the final tuning of a circuit, a speaker cabinet's loading or accessory—hifi talk might call it voicing—are resolutely his domain. This extends to concert halls, recording studios and remasters using the XRCD24 process of which he is a co-patent holder. He'd thus offered me one of his Hi-Q Records at the show to use as a reviewing reference. I picked the Bach Violin Concertoes with Yehudi Menuhin (and Christian Ferras for the Double Concerto in D Minor).
With the Munich show faded in the rear-view mirror of our compact but quick Volvo C3 T5, I sifted through the amp's small print whilst thinking about what I'd just read. Now I saw a note which seemed way out of tune with the above: a power consumption figure of 95 watts. As we know, single-ended operation means class A bias. That means the most inefficient of power conversion schemes extant. With the KAP-777's claimed power, one expects far higher consumption and even greater dissipation surface. Take my 30wpc Pass Labs X30.8. It weighs a lot more due to its studlier metal work and far larger transformer; and it dissipates 375 watts at idle. That's more than 10 times its power rating. Which is proper class A bias.


Without Reimyo's sparse wording mentioning a sliding bias, the power versus consumption figure was way off. Whilst waiting for Kiuchi's reply, I hit Google for Wojciech Pacuła's review. In it he quoted Reimyo with "in each half of the signal works a single Mosfet", then followed up with his own "probably this is a single-ended circuit which works in a balanced setting, bridged." Impossible!* Kiuchi: "I answered your question about 2-ohm power but want to discourage actual 800w/2Ω drive. Regarding single-ended operation, that is what we do state but to be more critical, we should call it semi-complimentary push/pull with one transistor per phase. Since such a description might confuse the reader, we call the amp single-ended. But the circuit is actually balanced and should be used with the XLR input for best sonics. We provide the shorting pin because our own preamp has no XLR."


With all due respect, calling the KAP-777 single-ended is far more confusing. Many could find it deceptive in fact. But once we adjust the terminology to class A/B push/pull, the otherwise underspec'd dual-mono 400-watt Brando-sourced power toroids fall in line. So do the shallow heat sinks. It simply meant that the Reimyo wasn't as rare a bird as I'd first thought. But when things read too good to be true, they usually are. Using 400-watt Mosfets for just two transistors per channel still wasn't exactly common. Whilst my $1'200 April Music Stello amp also is such a 'single-ended push/pull' affair as Simon Lee refers to it far more accurately, it only produces 50wpc. And in the final analysis, circuit topologies matter squat. It's the results we're after. On that score, my high hopes for the KAP-777 remained undashed.
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* Whilst still contemplating possible scenarios for these specs, I'd asked Nelson Pass for insight without divulging the amp's identity. I figured if anyone knew of clever tricks whereby single-ended inefficiency could be boosted to arrive at such low power consumption, it'd be him. "I don't know what product this is but single-ended can only mean class A. There all the bias tricks don't raise efficiency above 50% in a perfect world; more like 30-40% in my experience. Push-pull circuits have more leeway but still won't be better than 50% in class A amplifiers no matter what trick is employed. This means that an amplifier capable of 800 watts into 2 ohms will dissipate more than 800 watts doing it. Of course there are tricks to lower the idle dissipation with class A push-pull stages. I refer you to my 1976 patent. You can bridge or balance (often the same thing) single-ended Class A output stages but that doesn't raise efficiency. I believe Bel Canto invented the phrase 'balanced single-ended', a descriptive oxymoron I have appreciated but I presume that their product had the usual inefficiency of single-ended class A. Nothing wrong with that otherwise, but it is not what you think of as 'standard push-pull'. I've seen amps claiming single-ended class A to observe that it described a single-ended voltage gain stage only, not the output stage; and a well-known amplifier claiming a single output transistor which nevertheless had two per channel. Part of the problem is that all these terms are trotted out without contextual information.


"The topology that would fit the description of 'one per phase' is the circlotron [basic schematic for floating-bridge push/pull circuit at right]. If that is the case, then it is a topology whose history in solid state goes back to Bongiorno's Sumo 9. It is interesting that circlotrons did not catch on. This is possibly because it is off the beaten path and a little confusing to a would-be designer who has only worked with the 'Lin' topology invented at RCA in the 50's (think HK Citation 12) which is the basis for most of what's out there."


For a bit of Kazuo Kiuchi history, he started Combak Corp. in 1970 as a distribution house for musical instruments with a focus on stringed specimens. By 1973 he'd expanded his assortment with loudspeakers from a then still mostly unknown British firm Bowers & Wilkins. He subsequently took over representation of Nakamichi and developed into Japan's largest dealer for TDK open-reel and cassette tape. But his special interest remained on historical string instruments which by 1990 led to scientific studies that birthed a new product range whose development and global distribution are handled exclusively by the Combak Corporation.


During the 1980s, then new computer analysis and simulation tech in university laboratories began investigating why Stradivari, Amati and Guarneri instruments enjoyed better sound than modern copies. Modal analysis stimulated an instrument in more than 100 different places to show surprisingly uniform resonance behaviour between the vintage instruments but quite different behaviour from the modern clones. Even violas and celli from the same Cremona masters showed uniform spectral resonances regardless of whether they were stimulated on the body, bridge, finger board or scroll. From this research developed Kiuchi's notion to apply the same unified resonant behaviour to hifi systems. This began with specially treated woods and metal alloys which he used as couplers between speakers and electronics and their support surfaces. The exploited principle wasn't damping but the strategic release of kinetic energies into harmonic resonance. That's why the Harmonix logo shows a tuning fork. It signifies professionally tuned products which are still crafted by Japanese musical instrument makers. They include various footers, turntable pucks, speaker stands and equipment racks. The logical next step was attention to the arterial connection system of cabling, leading to a Combak cable range of pure copper with specially tuned resonance behaviour. The next Harmonix focus was on the optimization of the listening room to tune its overtone signature via the company's various tuning dots, quasi precursors to Franck Tchang's acoustic resonators and related Stein Music inventions.


Since 1995, Kazuo Kiuchi has participated in CD mastering and pressing sessions of Yokohama's JVC studios and CD production plant to contribute his specific knowledge to their later XRCD developments. Not surprisingly, Harmonix products can be found throughout these studios. By 1997, Harmonix introduced its first Reimyo components to complete their ideas on the perfect playback system. Kiuchi is quick to stress that their focus isn't on revolutionary circuits. Rather, it's on well-proven solutions which their team's focus on resonant behaviour tweaks with in-house developed capacitors, transformers and hookup wiring. An obvious advantage for their multi-disciplinary collaborators is the ongoing involvement with JVC's studios where they can reference actual microphone feeds. Final members of the Combak catalogue are Enacom products (short for end audio compensator) originally developed by Japanese firm Enokido. Unlike other Harmonix products, these are electrical filters to tune back EMF and AC power. Wrapping up introductions, it's clear that Kiuchi-San's vision is holistic or systemic; and directly educated by his love of vintage Cremona-era stringed instruments and an applied understanding of their resonant fingerprints. We might perhaps also say that thin-walled deliberately active speaker enclosures from Harbeth and Spendor as well as Kiso, Ocellia and soundkaos would be conceptual distributed-resonance kin folk. Finally there is the current involvement of Gibson Guitars in hifi and more specifically, loudspeaker production. They apply standard guitar-building principles to speaker enclosure behaviour. In short, no idea ever remains an island. Soon others link up. What might have started as an isolated perhaps even 'alien' concept becomes an intermeshed network of related views and applications on an openly shared foundation. That's how progress works. It snowballs.