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The beast from the East. That appellation's already been taken by KR Audio's emphatically christened Kronzilla. Should the Bonasus become the warrior from Warsaw perhaps? The pugilist from Poland? 90 pounds of tail spin mass condensed into a roughly 16" x16" footprint feel utterly beastly once you're moving this amp into its final location while sweating your grip. There's iron galore on deck of this Polish panzer. Perceived value is through the roof before you've got the first tube plugged in. RCM's Roger even takes pride in the quality of the cardboard he uses for the packing. It's from the same vendor who supplies a major automobile firm to ship its engines. I truly have never seen this type of cardboard before. Oops proof to be sure. When I tell you that the Bonasus is built to a different standard, I'm not making things up. It starts with the felt-covered three-panel wood divider inside the shipping carton. Should you think of Poland as ex iron curtain, think iron curtain and forget about Thai silk in your windows. The Bonasus chassis is super thick to not flex under the weight of its four transformers and two chokes while presenting its circuit with a resonance-free environment.
To get at the high-voltage innards means removing massive Allen bolts, not measly screws. The bottom plate could serve double duty as engine protector for a 4x4 Rubicon challenger. Where others go glitz, RCM straps on a welding mask.
Next you'll think military formation when marveling at just how precisely the insulated thick solid-core flying leads have been set into right angles to be three-dimensionally routed and crisscrossed. This is about law and order, not a moshing snake pit. "Jawohl, Herr General" you mumble to yourself as you fire off an imaginary snappy salute.


It's clear that RCM approaches assembly on a highly skilled artisan level where exacting repeatability is a requirement. Roger claims that you could open 10 amps and compare the wiring. You'd find it identical as though robots had been employed. Not. These are done up by hand and a lot of protocol and procedure has been implemented to enable this level of guaranteed exactitude.


This clearly is a no-nonsense amplifier. There's plenty of evidence just how its designers must despise the oft-accepted kid's glove nature of certain prima donnas among high-end valve amplifiers.


Consider the meters. To confirm bias, there's two. The associated rotary control toggles between the left and right channel. That way there's a dedicated meter per tube. The amp is auto bias so no adjustments are necessary. The meters simply show when a tube's aging causes bias drift beyond what the circuit can stabilize so you know when to replace a valve. Should you fancy observing output levels while music is playing, the meters can be set to show that as well. Or not. Swell.

There's three status LEDs below the right meter. With the power mains on the rear apron off, none of them are lit. When the mains is active but the lower small rotary control still 'off', the LEDs will show red, yellow, yellow. The only thing active at that point are the logic circuits. In stand-by, all three LEDs go yellow. Now the tube heaters are on but the outputs are muted because the high voltage isn't applied yet. After the front panel control has been advanced to 'on', there's a 2-minute soft-start protocol during which the left yellow LED extinguishes and only two show yellow. When those two turn to green, the amplifier is operational and passes signal at its outputs.


Next consider the tube cage. You can simply slip it over the lateral retaining bars and call it a day. Still, RCM includes bolts and an Allen key so you can permanently fix the cover and probably pick the amp up with it had you a death grip, Titanium wrists and your weight shifted in an inhuman angle to overcome the seriously off kilter weight distribution of this beast.


There's absolutely nothing frilly, timid or half-assed about the Bonasus. It's put together like cars used to be that could be handed down from generation to generation. Now inbuilt obsolescence is the new world order and things are designed to give out after a few years to enforce replacements. From that perspective, the Bonasus is way old-fashioned. Ancient history in fact. The kind people still talk about while having forgotten already what happened yesterday.


But put your ear and hand on the transformers and nothing shakes, hums or vibrates even subliminally. All that mass just sits there silently awaiting your signal.


As you'd expect for a firm so obviously committed to sweating those gnarly details, there's a properly spiral-bound 6-page owner's manual and a 3-year warranty (3 months on tubes). The valves are Electro-Harmonix 12BH7 Golds, 6CA7s and Sovtek 5AR4. No NOS, no unobtainium, no insane maintenance bill. The amp was deliberately voiced around ordinary in-production glass. No nonsense to the max indeed is the operative leit motif here. I already knew that the Bonasus had been mated to Avantgarde horns at the last show. If it was quiet enough into 109dB horns, it'd sleep-walk with my 101dB Zus.