Power Amplifiers Technology Showcase
Mar 22, 2011 12:00 PM, By Mark Johnson
Applications for power amplifiers run the gamut from elevator music to brute force in a concert setting.
The cornerstone for any sound-reinforcement system is the power amplifier. Typically they're heavy and can generate a fair amount of heat. Traditionally, amplifiers were necessarily large owing to the fact that some of the required components themselves (transformers, heatsinks, and capacitors) needed to be large to adequately perform their functions. Advancements in technology and design (including switch mode power supplies and Class D output topology) have allowed for reductions in size and weight and have yielded amplifier models with the capability of extremely high output in a relatively lightweight package. This has enabled the development of multichannel designs (four, six, or even eight channels of amplification in one package) to be more practical.
The job of an amp in its most basic form should be "a straight wire with gain," meaning that other than amplifying the input signal nothing else gets changed, with many available models sporting nothing more than an off/on switch and channel attenuation for control. For the most part, that holds true today; however, the addition of digital signal processing (DSP) can greatly increase flexibility and facilitate adding more features to this basic audio building block, including but certainly not limited to loudspeaker processing and system management. Remote control and monitoring of critical functions including temperature and overload are also becoming more desirable, particularly in installations where the amplifier racks are situated farther away from the main control area.
Amps can be used for many types of applications from driving multiple zones in a retail establishment to the brute power behind the main system in a performance venue. We'll be looking at different offerings from the various manufacturers.
Ashly Audio's Class-H output KLR 4000 delivers 2000W per channel at 2§Ù. The 2RU amplifier features a switch-mode power supply; front forced air vents with removable filters; and LED indicators for power, signal, clip, and protection. Rear-panel controls include a gain switch (1V, 32dB, or 26dB sensitivity), a high-pass filter switch, and a limiter switch.
The BGW X5600 provides 1500W per channel at 4§Ù. Front-panel indicators include LEDs for power, signal, true clip, and protect. A continuously variable fan provides cooling, and the net weight is 62lbs.
The CPA650 commercial power amplifier from Biamp Systems provides 325W per channel into 4§Ù. The amplifier weighs 33lbs., it is 3RU high, and it features passive cooling and barrier strip input terminals. The rear panel allows for mounting of optional autoformers for distributed systems.
Bogen's M600 features 600W per channel at 4§Ù and two input bays accept a variety of optional input modules. The amp offers three operation modes: stereo, dual mono, or 70V mono. The amplifier weight is 46lbs. and takes up 2RU.
From the United Kingdom, Camco offers the Vortex 8 Silver Series, which provides 4400W peak power per channel into 2§Ù or 4§Ù. The V8 features a screen user interface with no external knobs or switches and UMAN network control. An optional plug-in DSP card is available for loudspeaker system management.
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