Power AmplifiersCrammed with sophisticated features including DSP, multichannel signal routing, and networked control, power amplifiers have become much more complex and challenge their designers to keep operation a 4/15/2014 6:31 AM Eastern
Apr 15, 2014 10:31 AM, By Bennett Liles
Modern TVs aren’t just TVs, phones aren’t just phones, and power amplifiers aren’t just amps anymore. Crammed with sophisticated features including DSP, multi-channel signal routing, and networked control, power amplifiers have become much more complex and challenge their designers to keep operation as simple as possible. Our present roundup includes powerful models for large-venue installation, as well as small devices for tight places, and it spans commercial and residential applications.
The nX3.04 4-channel power amplifier from Ashly Audio provides 3000W per channel at 2Ω, but the speaker outputs can be individually DIP-switch configured for 70V/100V operation, as well. The DIP switches can also be used for high-pass filter, limiter, and input gain. The front panel includes power switch and level controls along with LEDs for temperature, current, signal, clip, mute, bridge mode, protect, sleep, and disable. Inputs are combo XLR-1/4in. TRS jack plus Euroblock input connectors and the outputs are Neutrik speakON. The 28lb. chassis has extensive protection circuitry and continuously variable cooling fans. Each channel also has remote DC level control, and the unit features a <1W defeatable sleep mode, SMPS (switch-mode power supply), and automatic 120V/240V detection.
For a solution to multi-zone scenarios, Audio Authority offers the SF-16M with 16 channels of 50W power, 16 matrixed RCA input channels, and additional two stereo (four mono) Flexport inputs. The optional Flexport modules connect to the SF-16M through Cat-5 cable, allowing input of a variety of audio sources. The Flexport modules can be located up to 500ft. from the amplifier. Up to 10 audio overrides can be programmed and triggered by switch closure, IR, and serial commands. Ten preset sound scenes can be used and 10 groups can be set up for any number of the outputs to share volume ramping, muting, and source selection.
For use in Biamp’s Vocia systems, the modular CobraNet-enabled, 8-channel VA-8600 features channel-to-channel or device-to-device automatic failover. Each amplifier card is individually software configurable from 100 to 600W and for either low impedance or 70/100V output. Onboard DSP includes volume, ducking, EQ, compressor/limiter, speaker crossover, delay, and output gain. Two RJ-45 connectors provide redundant network connections for control of data and audio. Multiple units are identified in the system through the use of a rotary ID switch on each one. Speaker connections are made through heavy-duty removable terminal block connectors and the front panel has LED indicators for amp failure, clipping, stuck fan, heat sink temperature fault, signal peak, and signal presence. Outwardly identical to the VA-8600, the VA-8600c meets EN 54-16 certification for facilities of all sizes.
Primarily for contractor installations, the CKi 2400V 2-channel 70V output amplifier from Crest Audio can combine CobraNET audio and control on a single Cat-5 cable while providing rear-mounted level controls with removable knobs. In addition to the Euro-style input and output connection terminals, the front panel offers a labeling area and indicators on the front and back are for signal presence, active, protect, and ACL (automatic clip limiting). This model also features sequential turn off, fault I/O for connection to external monitoring systems, and PowerSave to reduce current draw and thermal emission while the amp is at idle.
Crown Audio has widened installation options with its DriverCore Install Network Series amplifiers including network monitoring and control using the HiQnet protocol over TCP/IP. This enables Crown’s Audio Architect and the Powered by Crown app to work with the amps. With digital BLU-Link and balanced analog inputs, the input priority router can set the normal input source and automatically switch to the other input if the source signal is lost. DSP includes LevelMAX limiters, input/output EQ, delay, matrix mixer, and speaker line monitoring. About the size a postage stamp, the DriveCore chip combines the amplifier driver stage into the power output stage along with the additional audio-signal functions. It also replaces up to 500 parts, significantly reducing part count and increasing reliability, all while maintaining Crown’s legendary performance.
Apr 15, 2014 10:31 AM, By Bennett Liles
For touring or installation, Electro-Voice markets the TG7 power amp with 3500W per channel in a grounded bridge Class-H design with a switch-mode power supply. The 2-channel unit has an LCD screen for setup and monitoring sharing the front panel with individual LEDs for level indication, bridged/parallel mode, power, standby, IRIS-net, protect, and mute. The amplifier can also be fitted with the optional RCM-28 OMNEO network and DSP module for grouping amps and other devices in remote monitoring and operation. The RCM-28 allows complete overview of system status and control of all system parameters.
At the other end of the size and power scale is the Extron MPA 152 Plus, a tiny quarter-rack space stereo device with 15W per channel at 4Ω. Its primary application is to drive two sets of 8Ω ceiling speakers, each set wired in parallel. In addition to its three inputs (RCA, 3.5mm mini, and captive screw), it features a defeatable automatic power-down timer that places it into a standby mode below 1W after 25 minutes of inactivity. It also has a clip limiter and a connection for an optional Extron VCM 100 or VCM 200 volume and mute controller or the VC 50 analog volume controller for remote operation, an unusual feature for such a small model.
Galaxy Audio offers a solution to both fixed and mobile applications with its G-Series amps, and at the top of the line is the G1200 with 400W into each of its two channels at 8Ω. All of the G-Series models have XLR and 1/4in. input terminals teamed with twist-lock output connectors. The front-panel LED indicators show power and bridge mode along with a signal and clip for each channel. The amp is thermal, short and DC-protected with individual front-panel level controls on a 2RU chassis. The G-Series also includes the G-440 and G-850 models.
The quiet little CSA-2120 2-channel power amplifier from JBL is convection cooled and it puts 120W into each channel, going into automatic standby mode and disabling the amp’s pulse width modulation generator in the absence of an input signal. Protected from overheating and low voltage, the unit has detachable Euroblock input and output connectors. The optional transformer module can be used for connection to higher impedance speaker systems. The level settings are screwdriver adjustable, and each channel has clip and signal presence LEDs. A rear-panel DIP switch can be used to set the auto standby as well as a 70Hz high-pass filter and peak limiter for each channel.
For covering multiple rooms or zones from a hidden source, Knoll Systems has a solution in the Q450, which has four 50W stereo amplifiers in one housing and is operated by remote MR44 keypads. For operation by third-party control systems, the Q450RS model can use serial control. The MR44 wall-mounted keypads feature backlit buttons in addition to volume, bass, and treble control. Balanced input wall plates may be located up to 1,500ft. away and are available with Bluetooth receivers. Four stereo input sources can be selected and controlled. If additional power is needed, the four line level zone outputs can be used to feed larger external amps.
At the top of the IPD series line of amplifiers by Lab.gruppen, the IPD 2400 provides big power in a small, 1RU space. Delivering 1200W into each of its two channels at 4Ω, the IPD 2400 incorporates a DSP engine offering 40 realtime multi-slope parametric EQs, adjustable gain, input and output delay, and high/low-pass filtering. The controls for DSP and limiting are on the front panel in the form of two navigation buttons, a rotary encoder, and backlit display. The IPD LoadLibrary provides a number of Lab.gruppen released preset configurations. The standard AES3 inputs can be set for automatic failover to analog, and there is mix capability for all four inputs. Outputs can be connected on binding posts or Neutrik speakON connectors.
Apr 15, 2014 10:31 AM, By Bennett Liles
A proven design both on the road and in fixed installations, the FRS series amplifiers from Mackie have multi-speed fans that adapt to the operating temperature and minimize noise. The more powerful of the models is the 2-channel FRS-2800 with 1300W into each channel at 2Ω and up to 2800W in bridged mono mode. Six-segment LEDs are used for metering on each channel, and the amp is protected from shorts, under-impedance loads, over current, and overheating. The inputs have space-saving XLR/TRS connectors and looping XLRs while the outputs are on NL4 and binding posts. There is also a third NL4 for bridged mode output. Capable of sending high power into multiple zones, the 2RU Ottocanali series amplifiers also have redundant switch mode power supply for mission critical reliability.
Powersoft Audio has designed the 12K4 model with 1000W into each of eight channels at 2Ω and 1500W into each channel in 70V/100V operation mode. Equipped with multi-function DIP switches on the rear panel for impedance, voltage, and filters, the 12K4 also has individual attenuator settings for each channel located behind a front-panel cover. Every channel also features a switchable power-saving mode in which the amplifier goes into low-power operation when there is no signal for more than four seconds.
The CXD Series power amplifiers from QSC are built to allow greater installation flexibility using Flexible Amplifier Summing Technology (FAST), which allows the total power of the unit to be spread across one or more of its four channels. The CXD4.5 model delivers up to 1600W (burst) into each of its four channels. Onboard DSP provides crossover and parametric EQ filters, limiting, and alignment delay while all setup parameters can be stored in up to 50 presets. Controls and indicators include power, channel selects and mutes, input signal, and clip LEDs along with navigation and selection buttons for the front-panel LCD screen. This detailed screen can be used to show a wide variety of preset values and setup parameters.
Multi-channel performance in tight spaces is the specialty of Rane’s MA 4 4-channel, 1RU amplifier with its remote level controls and individual input sensitivity settings. The optional VR 2 wired remote mounts in a standard electrical wall box and allows level control from within its zone. In addition to level-indicating LEDs, the front panel provides compression and limiting indicators as well as ready, fault, and load lights. On the rear panel are DIP switch settings for master/slave operation, high-pass filtering, and compressor/expander. With 100W into each channel, the unit is well suited for small conference rooms, paging, and background music applications.
Speco Technologies designed the P500A Class D amplifier to drive large numbers of commercial speakers with 500W RMS power into a single output that can be used for low impedance or 70V/100V systems. Equipped with an auxiliary high-level XLR output, the unit can feed more amps to scale up the installed system. The front panel of the 2RU chassis includes LED indicators for protection notification, clipping, and signal presence along with a rotary level control.
Apr 15, 2014 10:31 AM, By Bennett Liles
Where small size and power are needed with high-end features, the DSP 100-2 from Stewart Audio brings three gain stages, filtering, compressors, limiters, and parametric EQ to a half rack space. This model puts 100W into each of two channels in 70V/100V operation, and it is convection cooled for quiet running. Optional Dante or CobraNET cards can be factory installed to accept two channels of audio over the network, pass them through the DSP, and on to the outputs. Along with the remote volume control terminal, there is a USB port for configuration and a screwdriver adjustable gain pot for each channel.
TOA has a wide selection of power amp models in the DA series. The DA-500F-HL delivers 500W into each of the four channels at 70V or various other power/impedance levels up to 1100W into two channels at 16Ω. Protected against overheating, overloads, shorts, and unusual DC current, the 2RU case has its inputs on XLRs and removable terminal blocks. Front-panel input/output signal condition LEDs are augmented with remote connection points for power supply, protection status, and fan operation in addition to on/off control. A signal at the input of channel one can be routed to all channels and individually adjusted with each channel’s gain control.
Yamaha Commercial Audio has configured the Nexo NxAMP 4X4 for scenarios in which both high power and sophisticated DSP are needed. Its ability to send up to 4000W into its four channels at 2Ω meets large-venue requirements while the amp provides advanced condition sensing and control using twin DSPs with increased processing power. Front-panel level controls have surrounding LEDs with centrally positioned mute buttons and the 2x40 character LCD panel shows setup parameters. Each input channel also has signal sense, peak, and protection LED indicators. Options include Ethersound networking and remote control through the Ethersound protocol and ESmonitor software.
The 2-channel, fan-cooled AP4K amplifier from Yorkville Sound can output 1800W per channel to either a 2Ω or 4Ω load using a selector switch on the rear panel. A three-tier Class-H design, the unit has defeatable peak limiters, high-pass filter, soft turn-on circuits, and multiple protection features. Inputs can be connected on XLR and 1/4in. terminals while outputs are on speakON and binding posts. The input connections for each channel are in parallel, allowing multiple AP4K amps to be connected for more power and distribution. The front panel provides level, limit, and clip LEDs.