I tested the amp with a Nash S-63 Strat-style with Lollar pickups, a Fender Road Worn Tele and a Hamer Talledega Pro. The KR-12 excels at big, clean tones: they’re warm and clear, with loads of headroom and full of nuance—they’re good enough to make the amp worthy of a recommendation almost on that alone. With just a guitar plugged straight into Normal 1 and the rig set up for a slightly-pushed clean, you can easily hear the tweed-era inspiration—and you could be forgiven for guessing it was running 6L6s. The mids are warm and forward, and they pick up a thick, sweet saturation when you push it harder; the highs ring out, and there’s plenty of oomph in the low end. The tone is balanced and very sensitive to pickup selection and touch. The Hamer’s humbuckers were lush and smooth, going from mellow, woody jazz tones to fat, full and bluesy. The notched tones from the Nash were nice and quacky without being thin.
Plugging into the first Gain input and cranking up both volume knobs about two-thirds of the way, I hit a sweet spot that made me stop thinking about how good the clean tones were. When it’s really working, the tweedy sound of the amp begins to give way to the more recognizably British flavor, with a distinct midrange grind, a smooth, even breakup, great dynamics that cleaned up with the guitars’ volume knobs. The Hamer produced a growl and bite, and the single-coil guitars went from lean, raw tones with lots of harmonic saturation at the top to howling and thick, depending on the pickups used. The most exceptional trait of both the KR-12’s clean and overdriven tones, though, is the decisively punchy attack, which it maintained with every guitar. The Tele’s bridge pickup, in particular, came through with a sting and sizzle I hadn’t heard from it yet, while the string definition and clarity remained.
This amp is also capable of delivering the big, blooming bass that makes for genuine old-school blues tones. I tend to prefer the low end a little tighter sounding, and I had no problem reining in low end simply by tightening the Damping control. While it may not be the best choice for bone-crunching, high-gain metal, there is enough gain on tap to pull off all but the hardest rock. I experimented with several of the recommendations Louis offers for achieving different gain structures by using the included footswitch or ‘jumping’ channel inputs with a few types of overdrive and boost pedals—a Hermida ZenDrive and Mosferatu, an Xotic BB+ booster and several BSM treble boosters. Cascading gain stages lent the amp a great crunch, sustain and harmonically rich distortion, and the particular voices of the different pedals came through without muddiness. Truth be told, though, I actually ended up spending most of my time playing the KR-12 with nothing between the guitar and amp but a 20’ Elixir cable. There are lots of possibilities to try out, so you’re likely to find more than one setup that suits you.
The Final Mojo
There’s no mystery why Louis Rosano’s amps are among the favorites of so many tone purists. The latest version of the KR-12 delivers on its promise of simplicity and true versatility, with tone to spare. These are great things to have in an amp that can establish an identity of its own in a musical environment so heavy with tradition. It stakes out a tonal territory that’s not based on any single style of vintage amp, it does a lot, and it’s very good at everything it does.
you're looking for an ace stage amp that will deliver any of the classic tones you want from it.
you need lots of modern features, or you're looking for a carry around combo.