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If you like the looks of a Kronzilla which is so undoubtedly advertising tubes to the nth power, you are definitely a tuber. With a very neutral preamp like the French D-Premier, all sound characteristics derive from the output tubes and their transformers. We also tried the SX-Eco with signal from the Audio Note Meishu's preout. Here a 6SN7 makes or breaks the sound as these tubes are quite microphonic. With a nice NOS Mullard the Kronzilla’s output got even valvier in the sense of rounding off. The sound with the D-Premier supplying the input signal was far more to our liking but some heavy tube rolling in the 6SN7 department could perhaps have hit upon more satisfying results.
As this Kronzilla is an Eco member we also assessed its merits in full transistor mode. With the tiny switch at the back in the right position, it was very soon very obvious how the two bulbous glass towers were out of the picture. The class A SET mode duly dissipates a lot of heat into the room. Cor’s idea for a parallel cool output stage was an absolutely valid extension of the SX's usability. With the Devialet switched to AIR, its proprietary streaming protocol fed from a Mac running iTunes with AIR interface, it was a breeze to find an Internet radio station of our fancy. Don’t look for high-end sound quality—that’s very hard to find—but talk radio is a different thing altogether. There are many interesting stations that broadcast something useful while one does some manual chores But don’t think the all solid-state SX-Eco mode is of poor quality.
This isn't KR’s first foray into transistors after all. In recent years there was the A150 HD, a weird-looking Harley V twin inspired contraption. Still current is the more regular shaped 50wpc A50 model power amp. It is that which was incorporated into the SX-Eco. Radio listening is fine for it but the quality of the transistor outputs deserves more. Whilst still in streaming mode a CD-quality download proved that eco mode works very well. It had nice tonality, decent soundstaging and plenty of speed. It was ideal for casual listening while reading or such But one has to remember that the real monetary payback is triode mode.
How about that value aspect then? Are €16.750 worth spending on a KR Kronzilla SX-Eco? That's a lot of money. For that sum you get a very heavy large industrial amplifier with child/pet-unfriendly monster tubes. The amp accepts only unbalanced inputs and is a bit picky on its power line input. That same pickiness applies to musical input sources. Not all preamps marry well and the very high input sensitivity rules out almost all sources with digital attenuation like a DAC as resolution will be compromised. The combination we tried and found favorable was with the Devialet as a combo source for vinyl, digital streaming and as fully configurable preamp. That machine itself will set you back around €13.000. Loudspeakers require another prenup. We found that only high-sensitivity speakers did extremely well. Here the 50wpc rating simply means steep headroom where the first handful of watts are the real deal and strong points of this gentle giant.
Other strong points are the solid-state driver stage which is what it is and remains stable over the years. The T-1610 tubes also have proven their reliability over two decades of being in production to be just as long-lived. That life expectancy is now even further prolonged with the addition of the solid-state output stage turning the SX-Eco into a worthy heirloom. Even later generations will still be able to enjoy its workings. Alternatives for the big Czech—pun intended—are classy 300B designs like Audio Note, Tron and Yamamoto which operate in that same sweet SET area but are exclusively tubed and not convertible.
The question we asked in the beginning—is the Eco addition just another fashionable selling point or wink at the craze— must be answered with the latter. With the eco option the Kronzilla SX has simply become more versatile.
Condition of component received: Excellent. Quality of owner's manual: Simple and straight forward. Website comments: Refer to distributor Musical Reality’s site for the most useful information. Human interactions: Great. Remark: The Kronzilla family is a statement amplifier series and one either falls straight for their strong points—audible and visible—or not.
