Amplifiers all being one box are doing their best to be separate boxes one per channel, splitting apart the signals to ensure when it reaches the speakers, you can tell that the singer is standing slightly to the left of the stage and the violins towards the right. Left is Left, Right is Right and Crosstalk is a measure of how much undesirable left signal is mixed with right output. The measure of this is the signal to noise ratio. The goal is to make this background noise imperceptible, this means you hear more of the music and less of the noise. An amplifier is the same, there is always a very small amount of noise from the electrons whizzing around inside. None of this is apparent when the kids are home with the TV blasting away, but that background noise is still there. The humming of a radiator or cars travelling down a nearby road for example.

If you stand in a quiet room, in the countryside, away from the hustle and bustle, you might notice noises you’ve never noticed before. Of course, speakers will have the biggest effect on sound, so choose some that are well matched to your listening preference. The lower this figure, the closer the output of the amplifier will sound to the original recording. More distortion generally means more colouration to the sound. Total Harmonic Distortion + Noise (THD + N) is a measure of just how much effect the amplifier has on the sound output. Hint: Be sure to look at speaker sensitivity, since this has a big effect. Generally, 10W is pretty loud for average listening and 100W is enough to blow the roof off most parties! The bigger the speakers or room, generally the more power you want (much to your neighbors and housemates dismay!) However, you probably don’t need as much power as you’d expect. Power output is roughly equivalent to how loud you can pump out music. When choosing an amplifier, look out for these specifications: We focus our efforts and budget only on specs that make a real difference to the sound you hear. At Cambridge Audio, we don’t go in for unnecessary complications.

Power amplifier for speakers