Pickups

The pickup is probably the most important part of your bass, it is responsible for your ability to hear the tone of the instrument as efficiently as possible. Many mass-produced instruments use very cheap pickups that give a poor quality signal to your amplifier and often colour your sound or miss large areas of frequencies making your instrument sounds thin, harsh or boomy and dull. Installing a good set of pickups can transform a bass guitar, and in most cases it makes sense to put higher quality pickups in your bass first rather than a preamp.
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