Choose the best bass amplifier by looking at its wattage, deciding on a combo amp or a stack, and determining the correct the size and number of speakers, as well as the number of channels on the amplifier. Most bass amplifiers have to be much larger than guitar amplifiers, because it is required to get an equivalent volume. Many of the decisions regarding choosing a bass amplifier hinge on whether or not you intend to play live, and whether you are a beginner or an experienced bassist. As with all aspects of music, the choice of bass amplifier is highly subjective, and what is suitable for one person may not be for another.
The wattage of the bass amplifier is essentially a measure of its raw power. Bass amplifiers need a lot more force than guitar amplifiers because the speakers are generally much larger. Players hoping to play in a band should get an amplifier that is between 200 and 400 watts, but stay-at-home beginners can make do with anything as little as 20 to 50 watts. If the player needs to practice with a guitarist or keyboard player, however, anything up to 200 watts may be needed. Essentially, more energy is required to produce low bass frequencies than comparatively high guitar ones, and driving an amplifier to its upper limit doesn’t usually produce a good tone.
A bass amplifier will either come as a combination amplifier — commonly called a “combo” — or a stack. Stacks are made up of a small head, which is used to control the specific tones produced by the amplifier, and a large speaker used to drive the sound, called a cabinet. Although stacks are generally larger and more powerful, combo amps are better for beginners and suited for most uses. Combo amplifiers bring both the pre-amp and speaker from a stack into one unit. This also makes combo amplifiers much more portable.
Many bassists think that a large speaker is always better, but others disagree. The decision is often between one or two large speakers and several smaller speakers stacked into an amplifier. This is a matter of personal preference, and a decision that is unlikely to be important to beginners. Experienced players should remember that a bigger speaker isn’t necessarily better.
Channels are essentially different groups of settings that can be used to get a different sound out of an amplifier. For example, a bassist with two channels on his or her amplifier could set one up to have pronounced low-end tones and a noticeable reverb, and the other could be set to produce a standard bass sound. A bass amplifier with two channels allows players to change their sound at the touch of a button. This is important if players want to alter their sounds mid-performance or with minimal effort.