Millie Goes Under the Knife

or, “Why You Should Always Buy A Guitar With The Pickup Pre-Installed.” To recap from the previous installment:

Our hero had an acoustic guitar with a tiny, tiny soundhole, into which he wanted to install a pickup-microphone-mixer/preamp system. Three local shops that do this kind of work turned him down. (Sam Ash guitar tech: “I can’t get my hand in there!”) Will the pickup make it into the guitar?

The iMix comes with a pretty decent manual, but the installation instructions were pretty hard to figure out; you can learn from my mistakes. If you break your guitar while following these instructions, please let me know so I can point and laugh.

Tools I used:

  • 1/2″ repairman’s taper reamer
  • Inspection mirror
  • Circular file
  • Sandpaper
  • Dremel (or a drill that will let you do delicate work)
  • Screwdrivers: Medium phillips-head and a micro flathead
  • Small pliers with a wide jaw
  • Masking tape
  • Brightly-colored toothpick
  • Metal ruler

Except for the reamer and the mirror, these are all pretty common tools. Please, do not use a standard drill bit if you’re too cheap to buy a reamer bit. It’s far too easy to end up with chipping and cracking around the endpin hole if you use a drill. A hand-cranked drill with very sharp bits might allow you enough control. I learned this the hard way when I was widening the tuning machine holes on a 12-string guitar. (Hell, I might lend you my reamer if you ask me nicely.)

StewMac has several reamers you can get, including one you can put into a drill if your drill has a slow setting. If there’s already a hole in your guitar, you could probably use a circular file to enlarge it if you’re good at precision work.

You can probably get by with any small mirror, but inspection mirrors are insanely useful. I haven’t used my reamer since doing this job, but I used my inspection mirror until it fell apart. They also sell them in auto parts stores.

You’ll need to clear the soundhole, the big ol’ hole that’s behind the strings. To install anything inside any acoustic guitar, you’ll need to be able to get at the inside of the sound chamber, which means going through the soundhole. I repeat that this is a parlor-sized guitar, and has a very small soundhole.

The strings are going to be in your way, and you can either remove or loosen them. I do the latter. A capo on the first fret, loosely adjusted, holds the strings taut so they don’t unravel around the tuning posts, where you’ve so carefully wound them. (Those of you that wind them in an ungodly mess up there can feel free to skip ahead.) Even in my in-a-real-band heyday when I put on a new set of strings on my main guitar every week, I never got this process down to less than ten minutes (and that included using a special adapter that allowed me to wind the strings up with a power drill). If you get the same pickup as I used in this tutorial, you’ll need to reach inside to change the battery. If you like, you can keep the strings off to the sides of the soundhole with some strips of velcro, or even just a little twine.

Secure the strings with a capo.

The next step is to ream a hole for the endpin jack. Depending on your guitar, you’ll need to widen the existing hole or perhaps even drill a new one. Where at all possible, use the existing endpin hole as a starting point. (I don’t know of any guitars without an endpin, but there’s always a first time.) There are guitars that have the jack elsewhere on the guitar, but you’d need to drill a new hole to install one of these.

I know of two common endpin types: Screw-in endpins, in which case you unscrew them and pull them off (carefully!), and the sort that are glued into an existing hole. In either case, remove the endpin carefully, trying not to chip the finish around the hole. (Do as I say, please, not as I did.)

The non-jack endpin.

Removing the endpin.

I replaced an endpin with an endpin jack. If your guitar has one of these that you’re replacing, you’ll need to reach around inside the guitar through the soundhole to loosen the nut that’s holding it into the guitar.

Reaming the endpin hole. (Inset: Reamer tool.)

Evening out the endpin hole with a circular file. (Inset: File tool.)

Endpin jack in the guitar. (Inset: A small chip in the finish.)

Before drilling or reaming, place a piece of not-too-sticky masking tape over the existing endpin hole, in order to minimize any chipping of the finish. A Dremel will drill a pilot hold just fine. (Although it did create some smoke from the wood as I was doing it… Seagull uses some damn hard wood in their endblocks.)

The endpin hole is never big enough for an endpin jack, and you’ll need to widen it. A reamer can still damage the finish if you’re vigorous enough, but there’s less of a chance with the tape holding the finish down. Tip: Keep yourself on your “kinder and gentler” setting for this job.

I used a circular file to do the fine touches, getting the hole just big enough for the jack. Fitting the endpin jack into the guitar… well, it’s a teeny, tiny guitar, and I can sympathize a little with the three folks who declined to work on it. It’s not so much that they couldn’t do the job, but that they didn’t want to risk breaking the guitar. (Or maybe it’s just that this job takes a lot of time; I’d imagine that on a guitar this small, this is true even of a practiced guitar technician.)

Positioning the microphone: The iMix system comes with a rig for positioning the microphone under the saddle, inside the guitar. This is where the inspection mirror starts to be useful.

Rig for positioning the under-soundboard microphone.

Mic placed under the soundboard, seen through an inspection mirror. The wire leading out of the endpin jack can be seen in the background.

Unlike previous pickups I’ve installed that are a piece of rigid metal, the Element pickup is a flexible piece of braided wire. It fits under the saddle, threading through a hole drilled through the soundboard, and it ends in a plug that fits into a jack on the preamp.

L.R. Baggs “Element” pickup before installation.

Scribing a guide line on the saddle. (Inset – Saddle removed to show scribed line.)

Drilling a hole in the saddle for the pickup. (Inset: Cleaning the hole with a file.)

Checking the location of the bridge hole after drilling.

Drilling a slot in the other side of the bridge, for excess pickup length.

Feeding the pickup through the hole in the bridge.

Adjusting the pickup to fit. (Inset: Pickup ready for the saddle.)

Sanding the saddle down. (This is to adjust for the height of the Element pickup and make sure the bottom of the saddle is flat, to contact the pickup properly and transmit a good sound to the system.)

After sanding, you should checked that the bottom of the saddle is flat.

Reinstalling the saddle on top of the pickup.

The preamp installs with a sticky pad that comes in the box. You’ll want it placed so you can adjust the switches by using a screwdriver you poke through the strings into the soundhole. (I put the battery case to the left of the preamp after taking this photo.)

Installing the microphone element: I was worried that, if I measured wrong, I’d end up drilling through the mic I installed under the bridge. There’s a little crack in the bridge, so small that it might even have been there before. I think I should fill it in with some putty or something before proceeding, actually.

I stopped off at Central Jersey Music, the best music tech shop in the area, and they confirmed that the best way to rout out the extension under the bridge was to use a Dremel bit and then file it smooth. I learned to listen o their advice a long time ago. Once I didn’t do as they suggested, and it’s a good thing the tuning machines I was installing (mostly) cover the mess I made of the finish on a 12-string guitar’s headstock. (Again, this is what happens when you use a drill where you should really use a taper reamer.)

Threading the pickup in was easy compared to hooking up all the electronics and, oddly enough, installing the battery for the first time.

The pickup/mic system sounds great! I can play it loudly without feedback (my neighbor knows this well). There’s a crackling sound when I change the volume or the balance between the pickups, though. The manufacturer seems to feel this is probably the control dials, and can be replaced. Overall, the iMix is good for amplification in small rooms. I wouldn’t want to use it at a large concert, or at least not the microphone. The pickup gives feedback at very loud volumes, even when used without the microphone. But for good sound, it’s hard to beat this system.


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