Chapter 6 discusses the effects that different amplifiers and loudspeaker cables can have on the overall performance of loudspeaker systems. The can be seen as highly controversial aspects of the systems, especially in the world of ‘hi-fi’, but in terms of the accurate sounds required for monitoring, the situation tends to be rather more straightforward. The different amplifier ‘classes’ are explained, along with some of the component options, and the basic performance criteria are outlined for ‘transparent’ operation. The properties of loudspeaker cables are investigated in some depth, including extensive research carried out by the authors under controlled conditions. The chapter concludes with discussions about multi-cabling and multi-amplification, which relieve some of the demands on the cables.