You have plenty of audio amplifiers to choose from here at Instruments4Music, with the main decision being whether to go for a traditional analogue power amplifier, or a digital type of autio amplifier. Generally you will pay a little more for the digital audio amplifier, but they are much lighter, so if you are constantly on the move the digital solution may be best. Some consider the low frequency response and dynamics better for analogue power amplifiers, but modern digital designs have overcome many of the original problems and the low frequency response is excellent. 

See More
Page 1 of 1
There are a huge range of powers available, so there should be something to suite any system requirement. You could consider bridging smaller amplifiers to drive bass loudspeakers. This is often a good solution if you have one one bass cabinet, used in mono and combine this with stereo mid tops. This technique eliminates ending up with a  spare channel in the second amplifier, so can save a little money and weight. Another option is to use a three channel power amplifier, these are often configured with a larger third channel, making it suitable for driving sub-bass cabinets. Along a similar line, many of the amplifiers have internal filters or crossovers, so it can often save money to buy one of these, if you are planning an active system. Wiring complexity is also reduced. Power amplifiers are often called slave amplifiers, there is no difference, just the terminology, so don’t let this confuse you.