Reimyo CAT-777 MK II and KAP-777 [pdf] - Harmonix by Combak

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Preamplifier and Power Amplifier Reimyo CAT-777 MK II and KAP-777Double mono: the insides of the CAT-777 MKII are designed symmetricallyright down to the length of the cablessimple a circuitry as possible – similarto the single-ended circuit for a 300Btriode amplifier – yet much morepowerful. Mr. Kiuchi spoke about howextremely tedious and difficult it was tocomplete this project, despite all theengineering and technical assets andcapabilities available to him as the chiefexecutive of the Combak corporategroup. What they finally wound upusing was a single MOSFET transistorin what many would consider as being avastly oversized environment. For all ofthose who look inside the amplifier anddiscover a second transistor: This one operates in opposite phasewith the primary MOSFET and gives it a push, so to speak.Functionally it resembles how a vacuum tube with the associatedoutput transformers operates. Nelson Pass popularized thisprinciple with his Aleph circuits.What surprised me was that this one MOSFET per channel inthe KAP-777 was given cooling fins with such an enormoussurface area. Regardless of the performance demanded of thispower amplifier – it is capable of a steady output of 200 watts at8 ohns and 400 watts at 4 ohms – the device always remainedcold. This behavior, according to Kiuchi-san, reflects anobservation that gradually emerged over time: Changes intemperature always have detrimental effects on sound quality.These he minimized through mechanical cooling and an allegedly64 image-hifi.com 1/2013
permanently switched off MOSFET or one that is not alwaysgetting the full dose of voltage; in other words: a circuitsimilar to a Class A type, but without all the downsides of aclassical Class A. Exclusively designed and manufacturedcapacitors ensure the unimpeded flow of energy. And even theinside wiring was apparently custom engineered for thisReimyo power amplifier. Not to mention the tuning feet – thespecialty of the house of Kazuo Kiuchi so to speak – which healso specifically designed and built for securely connecting tothe KAP-777.Immensely more conventional than the new poweramplifier is the revised version of the CAT-777 vacuum tubecontrol amplifier, now featuring an MK II in its name. Hereagain the name bears the Japanese lucky number 7, this time intriplicate representing the three pillars underlying Kiuchi-san’sequipment development activities: the art of recording andmastering, Harmonix resonance technology, and high-techaudio engineering. His path to the MK II version was not avoluntary one – the fact that sets of NOS tubes for the oldCAT-777 were no longer available in suitable quantities and atreasonable prices made a change in design inevitable. In theend this led to an extension of the upper frequency limit from100 kHz to 200 kHZ, and this within a circuit without globalfeedback. On top of that we now have a volume control thatwas specially made for Reimyo by the Japanese componentsmaker Amtrans. The other assemblies are also of only theutmost quality and include inside wiring – again speciallymanufactured – with extremely low impedance, in a definedsignal direction, and with a minimum number of solderingpoints.Compared to the two alternately used preamplifiers fromKondo, the vastly more economical performance provided bythe CAT-777 MK II was magnificent. Tim Hardin’s “If I WereA Carpenter” from his second album (Verve Forecast FTS-3022) remained virtually unchanged in terms of body andproximity, his voice exhibited a little less softness ofexpression, and the contours of bongos in the middle were agrain less acute. In “Red Balloon” which followed, thepreamplifier displayed its remarkable ability to reproducedynamic contrasts in all their splendor and subtlety: from theexplosive lead by the guitar at the right in the beginning,which comes at you unblemished, to those times when Hardingets really soft on the last syllable of “red balloon…” and hisvoice almost vanishes. And yet it doesn’t vanish, but remainsdefined with the utmost sentience in even the quietest ofmoments. In its rendering of resonance and tonal qualities, thispreamplifier makes you quickly forget that this ability has longThe black Enacom filters are used only toeliminate front LED interferenceHand-wound film capacitor(black jacket, yellow wrapper)Discretely designed level control with goldcontacts from Amtransimage-hifi.com 1/2013 65
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Reimyo CAT-777 MK II and KAP-777 [pdf] - Harmonix by Combak

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