How to Set up Power Amplifier

A power amplifier for a PA system boosts your audio signal through loud speakers so that the public is able to hear. Setting up your power amplifier correctly is essential to getting the best signal to noise ratio, which results in the cleanest and most desirable sound.

Instructions

Difficulty: Challenging

1. Know your space. The most important element to getting your power amplifier to fill your room with amazing sound is to know your room. If it is somewhere you are familiar with, this step should be fairly easy, because you have an idea of how much the room needs and can handle. If it is a space you haven't worked in before, consider room elements like size, shape and surface materials.
2. Check the back of the amplifier for its power and resistance ratings. The wattage rating will tell you how much power the amplifier can put out. This is a determining factor for how loudly your amplifier will be able to fill the room. The resistance rating, in ohms, tells you the minimum resistance your speakers must maintain.
3. Do some math. This is tricky because the math will go against how you would normally think. For instance, when you double the power rating from one amp to another, for example a 100 watt amp to a 200 watt amp, the increased output headroom will be 3 decibels. It takes 10 decibels to double volume, so doubling power rating will not double volume. Also, resistance works differently than you may think. For instance, daisy chaining two speakers with an impedance of 4 each will equal a combined impedance of 2, not 8. So if your amplifier's resistance rating is 4, the previous example could damage your equipment. Spend some time researching how impedance works before you start connecting equipment.
4. Find your outputs. Depending on your amplifier, you may have one or several options for output connection types. Some common connection types are speakon, banana plug or XLR. There are other options so make sure you know what you are working with to avoid not having the right cables.
5. Set your level on your power amplifier. There is not a magic point that you should set your amplifier to. If you have your gain structure set through your preamps and sound mixer, raise the level of the power amplifier until the room sounds good and full. If you have not started getting levels, start with the power amplifier about 75 percent turned up and adjust as necessary.