Power Amplifiers – The Basics
There are many different types and configurations of amplifiers available from other manufacturers. In my experience, I have used 4-Channel and 8-Channel Amplifiers, Dual Channel (Stereo), High-Powered Amplifiers (over 4000 – 8000 watts per channel), 70-Volt, Mixer / Amplifier Combo’s, Car Amplifiers, and Single Rack Space Amplifiers. The main thing I have learned over the years is that there are “cheap” models and “high-end” models of amplifiers. Cheaper models may or may not work for what you need, and higher-quality amplifiers will give you the best quality (and are very reliable). Which amplifier do you need? It Depends! Having a basic knowledge of power amplifiers will definitely help with the decision-making process.
Dual Channel Amplifiers
These are the most popular type of amplifiers used in Live Performances and Permanently Installed Theater Sound Systems. This type of Amplifier has 2-Channels with equal output power. The Amplifier can be used as two separate amplifiers (Stereo), or you can Bridge the Amplifier and use it as one “Mono” amplifier. Also referred to as “Stereo” Amplifiers. The QSC Model# PL-380 PowerLight 3 Series Amplifier is shown below.
70-Volt Amplifiers
70-Volt Amplifiers have built-in 70-Volt Transformers that provide power to “Constant Voltage Speaker Systems.” 70-Volt amplifiers can power multiple 70-Volt speakers over very long distances. The QSC Model# CX-602V 70-Volt Amplifier (shown below) has a power rating of 600W per channel at 70-Volts and 550W per channel at 8-ohms. 70-Volt Systems are covered in more detail on our technical eBook.
Multi-Channel Amplifiers
There are also many types of “multi-Channel” amplifiers available. I’ve worked with many 4 and 8-channel amplifiers. These types of amplifiers are great for special applications. For example, we needed 6-8 sound effects played at different intervals in a large hallway. An 8-channel amplifier was designed into the system and did the trick. No need for multiple amplifiers – one multi-channel amplifier worked perfectly. The QSC Model# 404 amplifier (shown below) was my “go-to” workhorse amplifier for many systems over the years.
Networked Amplifiers
As previously stated, the “Digital” world is here, and amplifiers with built-in Networking capabilities are becoming more common than ever. Newer networking technologies allow more control, streaming audio, and faster communication. With these new technologies, there is a demand for audio technicians to understand the IT (Information Technology) and networking parts as well. It would benefit any current audio technician to become proficient in networking.
Amplifiers are getting more efficient and packing more power and features – not to mention the incredible Networking capabilities. The CX-Q Series is an excellent example of this! The CX-Q 2K4 Model (shown below) is designed for the Q-SYS Platform, features four channels, capable of delivering customized power output loading, and has a maximum power of up to 2000 Watts.
What are Routable Mic / Line Inputs?
Once a Microphone or Line Level signal is connected to a “routable” input – it does not have to go directly to the amplifier. The Q-SYS software allows you to “route” any of the signals to other devices on the network or to any of the channels on the amplifier. For simplicity’s sake, all CX-Q network amplifiers now feature Q-SYS network connectivity and “Routable” Mic / Line inputs, providing additional on-ramps into the Q-SYS Ecosystem when you need them.
Eight bi-directional GPIO connections, accessible anywhere on the Q-SYS network, provide further control integration opportunities for third-party peripherals, such as Digital Inputs and Outputs, Analog Inputs, etc. GPIO stands for “General Purpose Input / Output.
Q-SYS CX-Q Series network amplifiers combine a legacy of robust power amplifiers, advancements in high-efficiency output devices, and native network transport, control, and monitoring capabilities. CX-Q Series features four-and eight-channel models capable of delivering customized power output loading and total maximum power of up to 8000 Watts. All channels have low impedance, 70V or 100V direct drive.
There are many types of Amplifiers and Technologies to consider for different applications. Amplifier selection is mainly a “subjective” process but can also be a “budgetary” decision as well. Are you interested in learning more about Q-SYS? There are several different programming/training levels available (check out the link below).
Combo Mixer / Amplifiers
Combination Mixer / Amplifiers are very versatile pieces of equipment when it comes to “Commercial” type installations. They come in many sizes and wattages and are very easy to set up and install. You can wire up a couple of 8-ohm speakers or multiple 70-Volt speakers. Combo Mixer / Amplifiers are used everywhere in the audio world (Malls, Airports, Restaurants, Offices, and Theme Parks, to name a few). Audio Technicians should make time to familiarize themselves with this type of equipment (as well as with 70-Volt Systems).
The rear panel uses Euroblock connectors for both the Inputs and Speaker Outputs. In this example, we have a CD player plugged into Line 2 and using the 70-Volt speaker output. For one of my installations, I installed 20 each / 70-Volt Speakers, tapped at 1 Watt each, connected to this exact Mixer / Amplifier. I got plenty of level, headroom, and it sounded great! Many features include Muting (Automatic / Manual), Music on Hold, Zoning, Auto Paging, Automatic Spiels, Multiple Mic / Line Input Channels, and more.
