Technology Showcase: Remote-controlled and Networked Power Amplifiers
Jul 6, 2009 12:00 PM, By Bennett Liles
New options for controlling your network from any location.
Using a three-stage, grounded bridge Class H topology with a floating-switch power supply, the PowerH Series from Dynacord offers high efficiency with minimum weight. The units, including the PowerH 5000, contain an integrated microcontroller for internal control, and they can be fitted with an optional remote-control module, the RCM-26, that is compatible with Electro-Voice IRIS-Net (Intelligent Remote & Integrated Supervision Network) for integration into a power amp network of up to 250 units. This is run from a PC using the IRIS software application. In this network, all operational states including power status, limiting, temperature, modulation, protective measure activation, and deviation of load impedance can be immediately detected and displayed on the PC, from any amplifier in the network. Programming may also be done to automatically react to certain operational anomalies. With the RCM-26 installed, the PowerH 5000 can also remotely adjust parameters such as power on/off, level, muting, filters, parametric equalizers, frequency crossovers, delays, compressors, and limiters. These and more settings can be stored as recallable presets. The series also features advanced protection circuitry in the form of the multistage Advanced Thermal Protection (ATP) systemwhich, in most cases, prevents the amplifier from switching off when the thermal load exceeds a critical level. The Mains Current System (MCS) prevents power amp breakdown from the activation of the automatic circuit breaker.
The P1200RL Precision series DSP remote amplifier from Electro-Voice is a 2-channel amp providing 600W in each channel at 4V and 850W per channel at 2V with the loudspeaker terminals on a rear-panel barrier strip. Network control of the Precision series amps is accomplished on a serial CAN bus with a capacity of up to 100 amplifiers controlled from one or more PCs. Each unit’s network address is set as a hex number on a pair of screwdriver-adjustable rotary switches on the rear panel. There is also a handy ground switch that can be used to lift the ground in some installations to break ground loops. The controlling PC is connected to a UCC1 USB-CAN bus converter, from which the network connection loops through RJ-45 connectors on the back of each amplifier. The wiring is terminated on both ends with a 120V termination plug. This wiring is accomplished quite easily when the amplifiers are rackmounted together for a large, centrally controlled installation. The front panel features LED indicators for power state, standby mode (auxiliary power unit on only), protect, out (audio signal present), maximum signal, and limiter. Up to eight user DSP presents can be stored in the individual amplifiers for recall in the case of network failure.
Billed as the flagship of the C Series amplifiers from Lab.gruppen, the C 88:4 uses Class TD technology for the transparent sound of Class B amps with the power efficiency of Class D for a total output of 8800W through 2V from a 2RU chassis. All four channels are bridgeable for 2-channel or 3-channel configurations, and each channel’s output is selectable between low impedance and 70V/100V operation. The voltage peak limiter on each channel is also configurable to match the load characteristics of the selected output configuration. All C Series amplifiers come ready for connection to a NomadLink network. On this network, in conjunction with the NLB 60E NomadLink bridge and network controller, DeviceControl software is used to display key amplifier parameters and to control power state and individual channel muting. The unit is designed primarily for permanent installations, and the input signals are attached on Phoenix connectors while the outputs are on screw terminals. Front-panel LED indicators notify the user of excessive output current, DC, high temperature, very high frequency (VHF), short circuit, open load, mains fuse protection, and soft start. These conditions are automatically checked every 6 seconds, and the amplifier returns to normal operation as soon as the abnormal condition has ended.
Introduced in 1996 by MC2 Audio and still going strong, the venerable MC1250 uses complementary Class AB bipolar outputs with a floating drive stage to deliver 1250W through 4V or 1800W through 2V into each of its two output channels. The 4V/2V switching is done on the rear panel, which also features a stereo/bridge mono switch and XLR input connectors of male and female type on each channel input for linking inputs. The remote-control feature is a fully functional bidirectional control via RS-485 on a rear-panel-mounted 9-pin D-sub connector. Two handy features save wear and tear on the loudspeakers: The mute switches fade up on release, and the power-on sequence, with inrush protection, begins in mute and fades the signal up to the previous level setting after checking the system. The level controls can be operated separately or linked, and there is a user-selectable clip limiter with Tight and Easy settings that tracks the supply voltage. Front-panel LEDs show levels on each channel along with limiting, fault and high temp conditions, 2V output load, channel mute, and bridged mode. If overheating occurs, the power is reduced to a safe level, protecting the unit without shutdown.
The Italian manufacturer Powersoft introduced the Digam K10 model a few years back to offer a high-power performance package in a very small, 1RU chassis. Using pulse width modulation (PWM) in the output, the K10 packs 6000W per channel at 2V into that small case with a variable-speed fan for low-noise operation. The PowerControl module is a standard feature on the K Series amps; using Powersoft’s PowerControl software, which can be downloaded from the website, up to 16 amplifiers can be remotely controlled through their connection to a PowerControl Hub, which can be cascaded with other hubs. Each amplifier’s network ID, from 1 to 99, can be set with two rotary switches on the rear panel. This defines the maximum number of amplifiers in the network. The control PC is connected to a hub through an adapter, and it sends control data through the RS-485 link to the PowerControl module on the rear panel of each amplifier. The rear panel features combination 1/4in. XLR connectors, while the outputs use Speakon terminals. The front panel features displays for load impedance, output power, mains voltage and current, defeatable gate selection, and clip limiters for each channel.
Designed for installations where there is little rack space available, the CX168 from QSC Audio provides 8-channel output in a 2RU enclosure. The unit can provide 100W per channel at 70V and 90W per channel at 8V with output bridging capability to configure it for 4-, 5-, 6- or 7-channel operation. Active inrush limiting eliminates the need for power sequencers by controlling inrush current. Rear-panel DIP switches are used to control clip limiters, high-pass filters, bridge mono, and parallel operation. Selectable high-pass filters help protect loudspeakers along with automatic safety features including DC, infrasonic and ultrasonic protection, thermal overload, and short-circuit safeguard. The front panel includes indicators for power state, signal presence, clipping, bridging, and parallel operation modes. For remote control and monitoring, a separate data port is assigned to each pair of channels in the form of a 15-pin D-sub connector. The data port on channels 1 and 2 is the master data port offering both control and monitoring for power supply status of the amplifier. The data ports can also be used to supply input audio. The two channels in any pair can be bridged independently for operation of devices requiring higher power such as subwoofers.
The TX6n from Yamaha is a 2-channel amplifier providing 3000W per channel into 2V, and it can be customized in hardware by the addition of optional mini-YGDAI input modules to suit the specific application including the ability to directly interface with CobraNet or Ethersound digital audio networks. An Ethernet port on the rear panel can be connected to a computer with Yamaha’s NetworkAmp Manager II software for remote control and monitoring of individual units or groups of amplifiers. Using Yamaha’s EEEngine technology, the CPU regulates fan speed according to the amp’s internal temperature. All TXn models offer 96kHz signal processing, and onboard DSP functions can be set up, saved, and recalled with front-panel controls that include a large LCD display. The front panel also provides LED indicators for alert, clip, signal presence, and channel muting, along with a power-status LED, standby indicator, link-activity light, and operation-mode indicators.
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