The Cloud Electronics CV4250, one of our favourite products, is a four-channel digital amplifier for 70v/100v line installations ideal for retail, leisure, commercial and industrial applications. Suitable only for 70 / 100 volt line commercial sound systems, it's rated at 4 x 250 watts, with 500 watts shareable between Channels 1&3 and another 500 watts shareable between Channels 2&4.

The amp can be connected to a network and controlled remotely over a standard Ethernet network. Remote monitoring is also possible with the use of an optional web monitor card.

Dante compatible with the optional Dante card - CDI-CV4.

On-board, user-configurable DSP enables great flexibility of internal architecture, and a wide variety of remote control options including Ethernet, RS-232 and DC: the latter providing compatibility with standard Cloud remote control plates. The amp can be used straight out of the box - it is not necessary to either connect a computer nor remove the lid to access internal jumpers to set primary configuration parameters such as input routing, which may be done using rear panel DIP switches. Where more advanced configuration options are needed, they can be easily accessed through the internal web server and an Ethernet connection to an external device.

The energy-efficient (Energy Star certified) Class D output stage dispenses with line output transformers, and offers great savings in weight and size over traditional designs of equivalent power ratings. Safety features include output DC detection, overcurrent protection, and thermal monitoring. A switch-on delay provides loudspeaker protection at power-up. The 2U steel enclosure uses variable–speed forced-air cooling.

The amplifier is available in 2 channel, 4 channel and 8 channel versions and all models have a total power output capability of 1 kW, shared equally between odd-numbered channels in any combination, and even-numbered channels in any combination. Thus the odd-numbered channels can deliver a total of 500 W and similarly, the even-numbered channels can deliver 500 W. This feature allows – for example – one multi-channel amplifier to drive loudspeaker systems in areas of a building differing in size, while optimising the overall power capability.

To save energy when not in use, an automatic power-down (APD) feature puts the amplifier into an ultra-low-current standby mode if no input signal has been detected for 30 minutes. There is also a remote standby / wake up function which can be activated via a simple external contact closure. Wake-up time is typically 200 ms.

In addition to the “soft” power switch and associated LED, there are four LEDs on the front panel for each channel: these confirm signal presence, peak level, activation of the protection circuitry and amplifier power status.

Many set-up options on the amplifier’s DSP section are configured via the on-board web server. This is accessed via the Ethernet interface from any computer or other device with an HTML5/CSS3-compatible browser application. DSP functions include input routing, level, limiting, 7-band Room EQ, hi-pass filtering, up to 1.5 s of delay and 5-band speaker optimisation EQ. Total flexibility of input routing permits an amplifier to be easily configured for multi-channel or parallel channel operation, bi-amping with full control of crossover parameters, or derivation of a separate channel for sub-bass use (model dependent). Additionally, it is also possible to redefine the sources for the auxiliary output sources, which also include Room and Speaker EQ sections, crossover filtering and level controls. Users can determine which amplifier functions are accessible on the hardware controls and which are only available via the web browser interface.

In addition to the Ethernet remote control, the ‘CV’ amplifiers are also compatible with the Cloud wall mounted RL-1 remote level control plate.

For further information, please see the datasheet.

Key Features

Amplifier:

• Advanced design of 2, 4, and 8-channel Class D power amplifiers
• Standard “out-of-the-box” Cloud amplifier functionality: requires no computer configuration or internal access for basic operation
• Transformerless output stage drives 70 V/100 V line systems directly
• Nominal power ratings: 2 x 500 W (CV2500), 4 x 250 W (CV4250), and 8 x 125 W (CV8125)
• Thermal protection, overcurrent limiting and DC offset protection
• Switch-on delay for speaker protection during power-up
• On 4, and 8 channel models, power sharing allows odd and even channel groups to deliver a maximum of 500 W each
• Per-channel, front panel LEDs for signal presence, peak level, protection activity and power status
• Balanced line level inputs
• Optional Digital Interface Bus
• Per-channel output level controls
• Rear panel input routing switches configure amplifier for manual selection of multichannel, stereo or mono operation
• Rear panel switches select 70 V line or 100 V line output levels
• Per-channel high-pass filter (65 Hz default frequency: adjustable in software) to protect against transformer saturation in 100 V/70 V line systems
• Balanced, line level auxiliary outputs with full channel functionality, configurable and controllable via software
• Independent Automatic Power Down on odd and even channel groups; minimises power consumption in absence of an input signal
• <3 W power consumption with all channels quiescent
• RS-232C serial port for remote control of all amplifier functions, including DSP configuration
• Compatible with standard Cloud RL Series remote level control plates (per-channel)
• Remote Power Down control input
• 3-way GPIO port for master mute function or fault reporting
• Variable speed forced-air cooling
• 2U 19” rackmounting units

DSP functions:

• On-board, per-channel DSP section providing extensive routing, filtering, EQ and limiting for all channels including the auxiliary outputs
• 1.5 s delay pool, freely assignable across all channels and aux outputs
• Simple DSP configuration via on-board web server; any device with a compatible web browser and an Ethernet connection can be used to perform setup
• Built-in DSP crossover configurations allow amplifiers to be easily used with 2-way speakers
• Crossover configurations allow derived LF sub output
• DSP-implemented 5-band parametric speaker EQ section
• Optional EQ presets for OEM speakers (under development)
• Optional web monitor card performs load impedance tests and reports out-of-tolerance results via a web interface or SNMP