Compact and practice amplifiers are generally made as combination or combo amplifiers where the amplifier and speaker is collectively within the same chassis housing. The design criteria for this range of amplifiers includes the fact that they must have a small footprint, be lightweight and portable, but also have some of the features included on stage amps such as overdrive or reverb.
Their practical purpose is that in a rehearsal situation they are easy to set-up and much more physically manageable than a full blown stage amplifier and will often include the ability to overdrive or distort the input channel. Output ratings are often no more than 10 or 15 watts on practice amplifiers and the speakers are likewise; small and often below 10 inches. In almost all cases the technology within these practice amplifiers is solid state and therefore does not utilise valves.
