Combination Amplifiers, or "Combos" as they are commonly referred, are popular with both guitarists and bass players; they also provide compact on-stage amplification for keyboard players.
Bass & Guitar Combo Amplifiers
Combos have been around since the early 1960s when manufacturers such as Fender, Vox and Selmer all produced 30 to 50 watt models for live use. Today there are many brands of combo for both guitar and bass along with a smaller selection for keyboard players with power ratings of up to 400 watts.
Compact & Transportable Device
Combo amps are generally easier to transport as all the necessary components are held within a single box, they also tend to be a little more compact and in most cases can be transported in an average family car.
Another benefit for some musicians is that there is little or no set-up time with a combo, there are no connecting or patch leads to wire-in so the amplifier can be ready to use almost instantly.