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5 Important Specifications To Consider When Choosing An Amplifier

At Cambridge Audio, we don’t go in for unnecessary complications. We focus our efforts and budget only on specs that make a real difference to the sound you hear. When choosing an amplifier, look out for these specifications:


1. Power output:

Power output is roughly equivalent to how loud you can pump out music. 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. Generally, 10W is pretty loud for average listening and 100W is enough to blow the roof off most parties!

Hint: Be sure to look at speaker sensitivity, since this has a big effect.


2. THD+N:

Total Harmonic Distortion + Noise (THD + N) is a measure of just how much effect the amplifier has on the sound output. More distortion generally means more colouration to the sound. The lower this figure, the closer the output of the amplifier will sound to the original recording. Of course, speakers will have the biggest effect on sound, so choose some that are well matched to your listening preference.

Hint: Lower numbers are better.

5 Important Specifications To Consider When Choosing An Amplifier


3. SNR (Signal to Noise Ratio):

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. The humming of a radiator or cars travelling down a nearby road for example. None of this is apparent when the kids are home with the TV blasting away, but that background noise is still there. An amplifier is the same, there is always a very small amount of noise from the electrons whizzing around inside. The goal is to make this background noise imperceptible, this means you hear more of the music and less of the noise. The measure of this is the signal to noise ratio.

Hint: Bigger numbers are better!

5 Important Specifications To Consider When Choosing An Amplifier


4. Crosstalk:

Left is Left, Right is Right and Crosstalk is a measure of how much undesirable left signal is mixed with right output. 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. The more crosstalk there is, the harder it is to pick out the positions of the instruments as stereo separation is affected.

Hint: With crosstalk, the larger the number following the minus sign (i.e. -60dB is not as good as -100dB) the greater the stereo separation.

5 Important Specifications To Consider When Choosing An Amplifier

5. Inputs/Connections:

Can you connect up everything you want to? You’ll want to make sure you have enough inputs for everything you’re plugging in! Remember the different type of connections, like 3.5mm for iPods, Phono for turntables and USB for laptops and home theatre PC’s. They all have advantages and when there are a few options, choose the one which provides the best sound quality.

Hint: We separate out phono stages in our Azur products, and guarantee best performance as the signals from a turntable are very small and can be easily interfered with.


So there you have 5 important specs to consider when you’re out and about shopping for your brand spanking new amp! Are there other specs we’ve missed? Make sure you let us know in the comments below.