Holes left from previous controls or preamps can be patched with matching wood, but it’s difficult to make this type of repair invisible. Photo by Brian Michael.

Pickups have become the standard way to amplify acoustic guitars, especially in situations where using an external microphone isn’t a viable option. As a result, many guitars include pickups and onboard electronics as standard equipment. But just like consumer electronics, pickup and preamp design evolves at a rapid pace, while acoustic-guitar innovations are comparatively slower. Some players find that just as their guitar opens up and matures acoustically, their amplification system has fallen behind the times. Does the pickup in your 20-year-old guitar sound like a rubber band stretched across a cardboard box? Or even worse, when plugging in, do you hear crackling noises and distortion? In this article, we will take a look at the options and limitations.

Why Upgrade?

There are two general reasons for upgrading the electronics in your acoustic guitar: to improve the guitar’s plugged-in sound and to replace malfunctioning equipment. The latter reason is usually obvious—the system doesn’t work at all, emits pops and crackles, or only works intermittently. It’s a good idea to have a professional repairperson assess the situation, but if a replacement is necessary, finding original parts for an older guitar’s electronics can be nearly impossible. Trying to diagnose broken electronic components can be time-consuming, and you could end up paying a repairperson as much to troubleshoot the problem as you would to have a new system installed.

But there are also reasons to upgrade a system that still works. Guitar electronics have come a long way since factory-equipped acoustic-electrics became common some 30 years ago. For example, many older systems were passive and had a weak output and thin sound. And some older pickups or preamps don’t sound as good as the latest generation, simply due to improved technology. Or you may want to upgrade or expand a relatively new system if you’ve come across something you like better or if you want to add a second pickup.

Undersaddle Pickup Replacement

Upgrading a Gibson CEC with an L.R. Baggs Element system. The Baggs soundhole control unit was replaced with full-size pots to fit into the Gibson�s stock control setup.

Undersaddle pickups have become the most popular, and it’s often possible to replace one model with another without much trouble. But there are a few factors to consider. One is the way the pickup’s lead wire is fed through the bridge. While all undersaddle transducers require the drilling of a small hole through the saddle slot and top, some (such as the L.R. Baggs LB6, EMG AT, and Fishman Acoustic Matrix) are angled 90 degrees to the top, while others (such as the L.R. Baggs Element and Ribbon Transducer, B-Band, D-Tar, and Highlander) need a hole drilled at about a 45-degree angle. The main concern is to avoid drilling though a top brace, which could structurally compromise your guitar. Most flattop guitars have top braces under the saddle-slot area, so it’s very important to make sure you don’t hit one with the drill bit. Since the saddle slot is usually tilted for compensation, you should try both ends of the slot because one may work better than the other. For example the bass side of the saddle slot may be closer to an X brace than the treble side, so drilling a hole through the treble side would be the best choice. In extreme cases, brace location may dictate whether or not a 90-degree pickup lead can be used at all. With transducers that need an angled hole through the top, the angle can usually be adjusted so the hole comes out on one side of the top brace.

Pickups that have coaxial cables, such as the D-Tar Timberline, Fishman Sonicore (used in several OEM Fishman systems), and Highlander, also require extra attention. These pickups are often installed in a semicircular groove in the saddle slot, and if you wish to replace one with a flat transducer, the saddle slot will have to be rerouted and possibly plugged and recut to provide a proper fit for the new pickup.

If your guitar has a split saddle, like Lowdens and many Takamines, your pickup replacement options are a bit more limited. However, many manufacturers offer special two-piece or Z-shaped versions of their undersaddle pickups, and two coaxial-cable units can often be combined in series and connected to a single preamp.

Tricky Installations

Even though modern undersaddle pickups are relatively simple to install in most guitars, there are instances where the bridge needs to be modified. For example, the adjustable bridges used on many 1960s Gibsons, as well as a host of Japanese guitars made during that era, need to be modified with a standard drop-in saddle before an undersaddle pickup can be installed. This involves removing the adjustable saddle assembly, filling the original bridge cavity with wood of the same type and grain orientation, and routing a standard saddle slot, followed by fitting a new nonadjustable saddle.

Preamp Replacement

Fishman’s Prefix series preamps have used the same size for years, and upgrading is a matter of a simple drop-in.

Besides the minor tweaks needed to make a new pickup fit, other modifications may be necessary. For example, the volume and tone controls, or entire preamp modules, built into the side of your guitar may not be compatible with newer systems. Also, not every pickup is compatible with every preamp, so it may be necessary to replace both. If your guitar has an older side-mounted preamp and its electronics are not repairable, upgrading the entire system is often your only option.

A modern system that uses soundhole-mounted controls can be modified by replacing the miniature potentiometers with full-size units, which can be mounted in the same holes as the old controls. But you may also want to use a new system with no onboard controls, in which case the holes in your guitar will need to be filled. An experienced luthier can plug the holes and touch up the finish to some extent, but it’s unlikely to ever look as if the hole was never there at all. This can be expensive, depending on how good you expect it to look.

Many acoustic-electric guitars built over the past decade use preamps that fit into a rectangular opening in the side of the guitar. In some cases a company’s newer units fit in the same hole as the old one, making it easy to replace or upgrade your preamp. Fishman’s Prefix series of preamps is a good example, and the ubiquity of Fishman’s electronics has caused other manufacturers to use the same dimensions.

If you find a new preamp with a larger footprint than your original, the hole can often be enlarged to accommodate it. To prevent cracking the solid wood sides, however, it’s best to reinforce the area with fiber or veneer with opposing grain orientation before cutting a new hole. If your existing hole is larger than any of the available preamps, you may be able to reduce the size of the hole with a custom-made bezel that fits the new preamp. But these types of modifications can get expensive. A less-expensive option is to leave the old preamp in place and use it as a battery compartment for a new system with an endpin-mounted preamp and controls in the soundhole.

If you decide to get rid of a side-mounted preamp and have the hole patched, the repair will be no different than a severe side-trauma repair, in which similar side wood is used to match grain and finish color. This kind of repair will be expensive, but on certain guitars it is worth it.

Mix, Match, and Add

If you want to alter the sound of your existing system, it’s sometimes possible to swap out individual components or add a second pickup or internal mic. Some onboard preamps are compatible with pickups other than those they shipped with. You might be able to swap a stock undersaddle pickup for a passive magnetic pickup installed in the soundhole, such as using an L.R. Baggs M1 soundhole pickup instead of the stock Element undersaddle pickup in an L.R. Baggs iMix system. Whether this is possible or not will depend on whether the impedance and output of each component is compatible (check with the manufacturers of each component if you have any doubts). If you have a match, you may only have to solder the correct plugs to connect a new pickup to your original preamp. Keep in mind that if you remove an undersaddle pickup and don’t replace it with a similar type, you’ll need to shim or replace your saddle to duplicate the guitar’s action.

Another option for altering your amplified sound is to add a second source, such as an internal mic or different type of pickup. Some of today’s preamps have extra inputs on the circuit board that allow you to easily connect a second source, and this is a sensible way to enhance your sound without starting from scratch. Ask your local pickup guru or contact your pickup’s manufacturer for suggestions. In most cases, there won’t be an easy way to blend the two sources on the guitar, so you’ll need to run a stereo or Y cable into two channels of an amp, mixing board, or blender preamp to control each pickup’s tone.

Preserve a Favorite Guitar

If you love your guitar, but not its amplified tone, a pickup upgrade is often worth considering. To avoid frustration, talk to an experienced guitar tech, as individual situations vary, and he or she can suggest workable options and will have the skills to install your new rig.

Brian Michael graduated from Roberto-Venn School of Luthiery in 2002 and is now on the repair staff at Gryphon Stringed Instruments.