Power Amplifiers

If you're using passive speakers you'll need a power amplifier to power them. Passive speakers are the best choice if you're planning to wall-mount the speakers in a school hall or village hall for example. As they're powered by the power amplifier they don't need to be plugged into the mains, making installation simpler.

If you want an installed system just for background music and announcements you probably need a 100 volt line system, and you'll find out more about those elsewhere on our website.

Once you've worked out how many watts you need for your venue and audience size you'll need to choose your PA system. Decide whether you want two, four or more speakers and make sure the sum of their power in watts RMS equals or exceeds the power you need.

Check the speaker spec for their impedance - they'll probably be 8 Ohms, but could be 4 Ohms.

Now, if you're using two speakers (e.g. 200 watts RMS @ 8 Ohms) you'll need a power amplifier that's capable of at least 200 watts RMS per channel at 8 Ohms.

If you're using four speakers (200 watts RMS @ 8 Ohms) connected in parallel - amp channel 1 to left 1 to left 2 and amp channel 2 to right 1 to right 2 - you'll need a power amplifier that's capable of at least 400 watts RMS per channel at 4 Ohms. Note that the speaker impedance is halved and the power is doubled when you connect two speakers per side.

Quad amps with four channels are available as an alternative and in that case you'd need each channel to be capable of at least 200 watts @ 8 Ohms.

If you're using six speakers (200 watts RMS @ 8 Ohms) connected in parallel you'll need a power amplifier that will operate safely at 2 Ohms.

If you plan to connect multiple speakers in series the impedance is doubled, not halved so you will need to calculate your power requirements differently to take that into consideration.

To make it easier for you, we've put together some Passive Speaker Packages with the correct power amplifier to power them safely. We always supply pictorial connection diagrams when you buy a system from us so you or your electrician understands how to connect it all together.