Fixing an acoustic pickup fast—it has to be onstage in an hour!

Issue 57 March 20, 2008

Pickup Repair-Gotta make this quick!

Fixing an acoustic pickup intro

Buddy Miller’s guitar has to be on stage with Emmylou Harris in 75 minutes!

Emmylou Harris’ “Three Girls & Their Buddy” tour performed here in Athens, Ohio. It’s a great show: Emmylou with Shawn Colvin and Patty Griffin backed up by Buddy Miller’s versatile guitar work.

Amplified acoustic guitars are a big part of this show. Among the forest of guitars on the stage, a standout was Buddy’s grand concert baritone built by Julius Borges. It sounded great, so you’d never guess that a few hours earlier it was here in my shop getting emergency surgery!

The Problem

Buddy had an undersaddle pickup installed a few days before, and now the two outside strings had almost no output compared to the middle four. This isn’t unusual; I’ll bet the installer had as little time to do the work as I had to fix it!

I offered to help, and Buddy brought me the guitar at 1:45pm. His sound check was scheduled for 3:00. That’s just an hour and fifteen minutes! No time to chat... gotta get to work!

First, check the slot

I checked the saddle slot for flatness with a Fret Rocker: if it's not flat, the tool will rock from end to end. It turned out to be flat but I found a few tiny, almost imperceptible, ridges in the slot bottom.

Checking the saddle slot with a Fret Rocker

I removed them with a micro chisel.

Cleaning the saddle slot with a micro chisel

Next, check the saddle

The middle of the saddle measured .123" on my digital caliper, but the ends measured .127".

Measuring the bridge saddle
Measuring the bridge saddle

Maybe that means the ends are too snug in the slot, keeping the saddle from moving up and down properly — explaining the weak output.

I marked the ends with a pencil, and stroked them over the coarse 6" fingerboard leveler to thin them. The pencil marks show where the file is working. Any remaining pencil marks indicate a spot that didn't get filed (could be a low spot). I put the saddle back in and strung the guitar to pitch.

It was now 2:15 and Buddy was standing in the shop waiting — nerve-wracking if you let it get to you! At 2:30, the output was better, but not perfect. I took out the saddle and thinned the ends a little more.

Filing the bridge saddle ends

If I had more time:

With a relief gauge, I’d measure the guitar top with and without string tension. The tension deflects the top by .010" (Figure 1). Armed with that info, I’d use a brace repair jack to lift the top by .010" and rout the saddle slot.

Relief Guage

(Figure 2) This simulates string tension, so the slot stays flat after the strings go back on!

Simulated string tension

Notice how Julius Borges numbers each of his bridge pins from 1 through 6 so they always go back in the same holes. Julius used fossil ivory pins for this beauty; he only cuts flutes into the two lowest strings — the others nest in carefully shaped, notched holes in the bridge.

Numbered bridge pins

Each pin is fitted by hand using a 5-degree tapered reamer.

Measuring the bridge saddle

Buddy’s happy!

At 2:45 the guitar was back to pitch. Buddy loves his Waverly tuners (he tunes this baritone to B, E, A, D, G, B from low to high).

Buddy Miller picture

The strings sounded lots better, and he'll play it in the show tonight for the first time. If there were a little more time, I think we could pull even more sound out of that transducer by experimenting with other string gauges. But it’s 3:00 and time for Buddy’s sound check. The show must go on!

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