1930s Gibson-made Kalamazoo KM-11 Flatback Mandolin

June 06, 2020

1930s Gibson-made Kalamazoo KM-11 Flatback Mandolin

A customer sent-in this old KM-11 for restoration and with this one he'll have a nearly-complete little Kalamazoo-instrument gang over at his place. I've always liked these pancake-style (instruments for their tone, feel, and volume... and as a bonus they have the familiar "Gibson A" body shape, too.

Intended as down-market instruments (though still built by Gibson right alongside Gibson-branded gear), the KM-11 has both a flat back and a flat top like the company's earlier Army-Navy and Alrite instruments. Unlike those, the bracing is a little heavier and the neck joint much more reinforced -- with a big old neck block supporting most of the fretboard extension over the top. That's part of the reason these hold-up better, too.

A lot of these need a little bit of love to bring the best out of them, but once that's been done they have a sound that fits somewhere between an oval-hole Gibson A and an f-hole Gibson A-50 in voice. It's punchier, chirpier, and louder than the average A but lacks the sweetness of them and it's not quite as zippy and snappy as a better A-50.

The neck has the same shape and feel as Gibson models, though, which makes it feel very "home base" to my hands.

Repairs included: a neck reset, fret level/dress, side dots install, new rosewood bridge, cleaning, and setup.

Setup notes: it plays perfectly with hair-under 1/16" action at the 12th fret, strung with gauges 36w, 24w, 15, 10. The neck is straight but the fretboard extension drops-off a little bit after the 12th fret.

Scale length: 13 7/8"

Nut width: 1 3/16"

String spacing at nut: 1"

String spacing at bridge: 1 5/8"

Body length: 12 7/8"

Lower bout width: 10"

Side depth at endpin: 2 1/8"

Top wood: solid spruce

Back/sides wood: solid mahogany

Bracing type: ladder

Fretboard: rosewood

Bridge: rosewood, comp'd