MANY A BUILDER OF BOUTIQUE AMPLIFIERS has gotten their start repairing
vintage Fender and Marshall amps. Louis Electric’s Lou Rosano says that
working on those classics gave him lots of insight into how to design
his own line of amplifiers, which range from virtual clones of Fender’s
’50s-era Twins and early-to-mid-’60s Marshalls to hot-rod models with
high-gain preamps. Rosano has made custom amps for Duke Robillard, John
Fogerty, Danny Gatton, and Hubert Sumlin, and he designed the KR M12 for
Keith Richards, who had originally purchased one of Rosano’s 25-watt
M12 combos. The more powerful KR M12 (Richards owns two of those) is a
plexi-Marshall/tweed-Fender-influenced design that features a
two-channel preamp with four inputs, and an EL34-powered output stage
(the amp can also accept 6L6s, 5881s, and KT66s). Pretty standard stuff,
but the KR is a surprisingly capable little amp that delivers the
signature tones you get from early Fenders and Marshalls, while also
offering enhanced clean and overdriven response.
The KR’s circuit is handwired on a high-grade phenolic board, and all of the pots, jacks, switches, and tube sockets are mounted to the aluminum chassis. The solid-pine cabinet is neatly covered in brown Tolex, and is constructed using half-blind dovetail joints for added strength. To help open up the sound, a quasi baffle made from a piece of birch plywood (which grips the rear mounted speaker) is attached to the inside of the cab’s inch-thick front panel.
The KR M12 packs a generous range of sounds, and this is primarily due to the Normal and Gain channels, which let you access a variety of different gain structures. Plugging into Input 1 on the Normal channel provides bright, crisp clean tones at very loud volumes (you can hit at least 7 on the Volume control with the Master cranked), and elicits progressively more saturated tweed-style grind as you sweep the Volume from 8 to 12. Input 2 is voiced slightly darker with a tad less gain, which could be useful if you have an overly bright instrument. If the KR only had the Normal channel it would still be impressive, as it gives you everything from pristine clean to moderately overdriven with a twist of your guitar’s volume control.
Input 1 on the Gain Channel ups the gain considerably, and this is where the old Marshall voicing begins asserting itself, yielding tough, tight-bottomed grind at lower settings (think of Keef on “Can’t You Hear Me Knocking?”), and stout distortion—perfect for wailing blues or rock leads—as you turn the Volume up past the halfway mark. The KR gets very loud at these settings, and this is where the Master Volume makes its case, as it allows you to bring the level way down without affecting the balance or compromising the dynamic feel.
To further boost the gain, keep your guitar plugged into Input 1 on the Gain channel, and then connect the supplied footswitch (using a standard guitar cable) to Input 2 on the Normal channel. This cool setup allows you to switch between grinding rhythms and very toothy solos—all with excellent articulation and dynamic response. Now if you want to go to the Santana zone, just plug the footswitch into Input 1 on the Normal channel. This produces a big increase in sustain from the cascaded gain stages, along with a bump in volume and a fattening of the lows. And even with all this added gain, you don’t lose any of the stringy detail from your guitar. Nice! This configuration is ideal for hard rock or old-school metal, as it allows you to footswitch between crunch and high-gain tones. And regardless of where the Master is set, the jump in level in the high-gain mode is just right for making a solo stand out. The abundance of purring midrange harmonics makes the KR extremely fun to play—especially in its distorted modes—and while the brawny character of the EL34s keeps the overdrive tones pointed in a decidedly Marshall direction, the sounds always clean up well when you turn down your guitar.
Wolf in Sheep’s Clothing
The KR M12 pretty much has it all—killer overdrive, rich old-amp grind, exceptional clean headroom. It’s compact, yet loud enough for stage gigs, and with such abundant tonal range, it has plenty to offer blues players, country pickers, hard rockers, and even metalheads. The fact that it doesn’t have reverb was of little consequence to me—and I dig reverb.
Bottom line: If you like the idea of an antique-looking combo that has you covered for everything from extremely clean to viciously distorted, you’ll love what the KR M12 has to offer.