5 four-channel power amplifiers around 250 euros tested

A small four-channel is still the cheapest way to control a complete car hi-fi system with just one power amplifier. The "standard model" has an output of 4 x 60 watts and can both relieve the load on a compact system using a high-pass filter and limit the top end of a subwoofer using a low-pass filter. In terms of power, the 60 watts into 4 ohms is sufficient for a compo, but there are more and more 3-ohm or even 2-ohm compos that tickle more power out of the amplifier, as the latter, as a DC voltage source, is able to loosen up more at the lower load. For the subwoofer, this means in practice that a 4-ohm subwoofer bridged to two channels can expect around 200 watts. This is just about enough if you want to operate a small sub with a high level of efficiency; on the other hand, there are power amplifiers that offer more than the standard output. Otherwise, the market today is not divided according to power, but according to size. Those who do not prioritise maximum power will find very compact amplifiers that are easy to install. Digital amplifiers, with their higher efficiency, are also better suited to being concealed and installed without great ventilation. After all, the factory radio is often still used these days. Here it is important to ensure that the amplifier is equipped accordingly. High-level inputs that can cope with the speaker strips of the original radios are a must, and the smartest possible automatic switch-on function is very practical if the vehicle does not provide a remote signal from the radio or an engine aerial. All of our test candidates are available from specialist dealers, where the car hi-fi professional will be happy to help you choose the right one.