Machine Heads

There’s no question: sealed enclosures with permanent lubrication are best. They insure simple and precise tuning..

Bridges and Tremolos/Vibratos

Bridges can be fixed (hard tail), like on a Gibson Les Paul or Fender Telecaster, but they can also be part of a tremolo/vibrato setup (a lever attached to the bridge which can temporarily slacken the strings and thereby change the pitch).

Bigsby tremolos, which date from the 40s, change the pitch around 1 to 2 half-steps. They can be found on Gretsch and Gibson hollow bodied guitars, amongst others, and are the vibrato of choice for many Country, Rockabilly, and Rock’n’roll players. If matched with a good bridge that’s correctly calibrated, it will usually stay in tune.

A Fender (synchronized) tremolo is partly built under the bridge and offers a greater pitch change thanks to a bevel carved into the body allowing for more leverage. The problem with this type of vibrato is that the guitar has a tendency to go out of tune.

The Floyd Rose tremolo( or locking tremolo) , popularized by Eddie Van Halen through such works as Eruption, evolved out of the Fender tremolo. The idea was to make a tremolo that would allow guitarists to drastically change the pitch of the strings without having tuning problems. In order to achieve this, it uses two string blocking devices, one at the bridge and the other at the nut. While this setup works very well, it is nonetheless quite awkward for changing strings, so beginners should be advised.

Pickups

There are so many different types of pickups that it is difficult to get a comprehensive overview. We'll focus on the two types most often found on guitars:

• Single coil: Historically, they were the first pickups invented for guitar. Though very sensitive to electrostatic noises, these pickups have nevertheless played a crucial role in the history of rock-n-roll, funk and soul. They have a sound range that goes from a dark and fat midrange found in P-90s to the bright and clear Fender Stratocaster sound. Thus, there is a distinction made between standard single-coil pickups and P-90 type single-coils, which are warmer and more powerful (Typical Examples : Fender Telecaster, Fender Stratocaster, Gibson LP Junior).
  
  
• Humbuckers (Dual coil): Invented in order to reduce noise(hum), they offer more power and roundness. For all types of modern music (jazz, rock, hard-rock, metal…). Humbuckers can be split ( Only one of the two coils is used to give a single-coil sound) on some guitars. Typical Examples: Gibson SG, Gibson LP…

Humbuckers can be split. In this case, only one of the two coils is used, in order to get a sound very similar to a single coil.

Note that pickups can be paired, in series or parallel, in phase or out of phase, depending on the guitar's built in circuitry. Thus one can create additional sound combinations and possibilities.

In recent years, bridges that feature piezo-electric pickups (those found on acoustic-electric guitars) have become more common. These can be combined with the standard pickups on the guitar.

Other Stuff

A final note: the presence of a truss-rod is indispensable for the fine tuning of your instrument, such as when changing the string gauge.