There could be a number of reasons for a guitarist to seek parts for their electro-acoustic guitar; damage and general wear and tear are both likely causes, but it is equally possible that the guitarist may want to improve the appearance or upgrade the tonal quality of the instrument. Many replacement parts for electro-acoustic guitars are also suitable for regular acoustic guitars, and vice versa, but it should be noted that only a limited range of parts can be replaced by the amateur. Most components aren't designed to be replaceable, and replacement will usually involve the skills and specialised tools of a guitar technician. This article will consider those that are replaceable and customisable by any owner with reasonable tool skills.
The headstock of a guitar carries the machine heads, sometimes called tuning pegs or tuning pins. These are the geared mechanisms which allow the strings to be tuned to pitch, and they are found in two markedly different styles, for nylon-strung and steel-strung guitars.
Machine heads intended for nylon-strung electro acoustic guitars will probably be in a similar style to those fitted to traditional classical guitars. These are mounted on metal plates, in two sets of three machine heads, with the metal plates affixed to the side of the headstock, and with the string rollers, either formed in plastic or celluloid, running across two long rectangular slots in the body of the headstock.
With this style of machine head, it may be advisable to source a replacement from the original maker of the guitar. The spacing between the tuning rollers should be standardised, as should the roller diameter, but there's always the possibility of variation between makers. If the rollers are too small or unevenly spaced, or if they're too big, this could lead to either problems with loose rollers, or the need to drill out the roller holes to the larger size. It might be good policy to see if the supplier will allow the replacements to be bought on a trial basis in order that the sizes can be double-checked against the old set after removal. If there is a mismatch, the new set could then be returned and exchanged for an alternative set.
On steel-strung electro acoustic guitars, the machine heads are secured to the rear of the headstock, with the metal tuning pin running through to the front, and held in position there by a bushing or ferrule. Again, if replacement machine heads can be purchased from the guitar maker, or can be found in the brand preferred by the maker if the maker doesn't manufacture their own, then these will typically be a like-for-like retrofit. This will allow the guitarist to re-use the same mounting and screw holes, with no need for any further drilling. This will maximise the possibility of a neat and tidy installation, without the original mounting holes being exposed.
The brand of the machine heads, and occasionally the individual model name or number, can often be found stamped or moulded into the head mechanism. If the identical brand and model cannot be obtained, there may be others available from aftermarket makers which are intended for that particular model of guitar. The pin hole sizes should correspond to a standard size format, but some modification may be required for older or vintage models of guitar. It is usually best to compare new sets with the old once removed from the instrument and before attempting to fit the new to ensure there is no discrepancy between the two.
If the guitar has a truss rod fitted within the neck, there are two possible locations for the adjustment nut. This will either be under the neck joint, and accessed from within the body via the sound hole, or under a cover on the front of the headstock, behind the nut. If this is found on the headstock, it is generally concealed with a plastic, or occasionally metal, cover. Replacements are available, but since the original is unlikely to fail, this is most often a cosmetic upgrade. Any replacement truss rod cover should be of the same size, or possibly larger than the original cover, in order to match or cover the original mounting holes.
The Nut, Neck, and Fingerboard
Although some of the components that make up the neck and fingerboard of an electro acoustic guitar, such as the nut, or the fret wire, are readily available as spare parts, it is probably best to leave their replacement and fitment to an experienced guitar technician or repairer. The skills required to fit them tend to be accumulated over many years, and often require the use of various specialised tools. While it is possible to buy nuts or fret wire from a number of sources, it is probably best for the guitarist to discuss requirements with their repairer, and take his/her advice on what should be fitted.
The body of the bridge is generally glued to the top of the guitar, and it is not designed to be either replaceable or adjustable.
An insert on the top of the bridge, the saddle, combines with the nut at the other end of the string to define the string length. In some cases, this can provide string length compensation. In many cases, the saddle is not glued or otherwise secured, and is held in place by string tension. Once the strings have been removed, or even loosened, the old saddle can be lifted out and a replacement put in place. The saddle could require replacement due to wear or damage, but an equally valid reason for replacement is to experiment with the sound of the guitar. Different materials, with different porosity and density, can affect the overall sound of the instrument, and the owner may want to experiment with a variety of saddles to judge their effect on the sound. Plastics and advanced polymers are the most common materials used by many makers and repairers due to cost and environmental considerations.
The electronic components of an electro-acoustic guitar consist broadly of a contact pickup, usually mounted below or within the bridge, a control unit for volume and tone, and an output jack socket, often mounted integrally within the strap button on the lower bout of the guitar. Advances have been made in this area since the introduction of the first electro-acoustics in the 1970s, and there may be benefits to be gained by upgrading the pickup, or by moving from passive to active electronics.
Many electro-acoustics have the pickup fitted under the saddle of the bridge, with the connecting lead running through the bridge to the control unit. Since there are differences in mounting styles between different makers and models of pickup, and in the way that the connecting lead is routed through the bridge, the guitarist should aim to purchase a new pickup that is physically similar to the old, or be prepared for some remedial work to the bridge and/or saddle to get a different design to fit.
Early electro-acoustics were fitted with simple passive volume and tone control setups. More modern guitars feature active preamplification, usually with a small control unit mounted in the upper bout of the guitar. If the pickup has been replaced on an older electro-acoustic, it may need a matching pre-amp, as the newer pickup may be incompatible with the older, passive volume/tone controls. Even if the guitar is a newer model with a pre-amp, the new pickup may still be incompatible with the pre-amp, requiring replacement of the pre-amp. Many preamplifiers are made in standard sizes, and use a standard mounting point, such that installation of the replacement, requires no woodworking or customisation.
The output jack socket, usually mounted in a combination unit with the strap button on the guitar's lower bout, rarely needs replacement, but if it does, there's very little to choose between one make/model and another.
How to Find Parts to Fit an Electro-Acoustic Guitar on eBay
From the eBay home page, select All Categories, and select Musical Instruments and then Guitars. From this point, a range of options emerge. Parts which are suitable for electro-acoustic guitars aren't necessarily specific to electro-acoustics – parts such as machine heads could be equally suitable for an acoustic or electro-acoustic guitar, and aren't specific to one or the other. Select Accessories, and then either to fit Acoustic Guitar or Electro Acoustic Guitar.
Replacement parts or accessories for an electro-acoustic guitar can be applied to repair worn or damaged items, but can equally well be used as enhancements to the appearance or functionality of the instrument. Although a number of upgrades will require specialist skills and tools, others are well within the capabilities of the amateur.