1960s Colombian Tiple/Octave Mandolin Conversion

Update January 2015: Just a note that I've updated this entire blog post with new pics and soundclip!

This came in to me via a trade and I was pretty excited by it, despite numerous old crack repairs and looming work needing to be done. Colombian tiples (rather than the smaller American tiples) are rare up here and fit in that 3/4 or tenor guitar size (22" scale, roughly small 00 body size) while traditionally being strung with 12 strings in 4 courses. They're also traditionally strung using a classical-style "tie block" bridge.

After doing structural work (cleating up and filling any cracks that hadn't already been taken care of, regluing braces, adding an extra brace under the fretboard extension), I leveled and dressed the frets, made a new nut, installed a tailpiece, and converted the bridge to a mandolin-style adjustable unit. I then modified the tuners down to 8 units and strung this up as a wide-nut octave mandolin. It sounds tops and is loud and proud, to boot. This thing really cuts.

I have no idea what the instrument is made of but it's all-solid and the build is featherweight. I love the classical-style rosette and the 12-fret style curvaceous body. The deep sides give it a strong bass response, too, with plenty of natural "reverb."

Removing all the extra tuners took a bit of time but the semi-stock look was worth it and recycled the tuners. They're cheapy Japanese units but work just fine.

My new nut is rosewood and I'm pretty sure the nut width is 1 5/8" across.

The neck is dead straight up until the 10th fret... after it the board slopes slightly down (like a reverse skijump). This means that "virtual" action is 1/16" at the 12th fret when dialed down as close as I'd like it but in reality the height measures a hair over 1/16" at the 12th fret. You don't really feel an effect when playing it except at the end of the fretboard... and it's a mandolin-family instrument, anyhow, so how often are you going to really get up there?

I added side dots, too.

The body shows many old, longer repaired hairline cracks. They were either fixed by me or a competent (though sloppy) older repairman. The top and back edges of the body are bound in a rosewood-y looking wood.

I modded the glued-on bridge to accept the new rosewood saddle and adjuster units. Intonation is good and the height adjustability is nice to have.

I used a "new old stock" Japanese guitar tail of the same age tand added some extra holes for mounting the proper number of strings. Gauges are 46w , 36w, 20w, and 13.5 plain for "octave mandolin" or GDAE low to high tuning. If you grab 2 sets of GHS extra light strings (10s), you can assemble the set needed for this with ease.

I also added strap buttons. This is so lightweight it begs to be slung around and taken everywhere.


Mat O'B said…
Man that's a beauty! If you find anything else for an octave mando conversion or a mandocello, I would definitely be interested.
Oscar Stern said…
I guess converting it from 12 to 8 Strings allows more room to play Chords w/o being too cramped. The Tailpiece helps relieve tension from the top. You can actually use 2 Sets of John Pearse #450 Strings (or as a 12 String version you'd need 3) as they're good gauges of 13, 20w, 30w, 42w.