Bosch PRAESENSA PRA-AD604 Amplifier, 600W 4-ch

• Flexible power partitioning across all channels
• Low power consumption and heat loss
• Full supervision with integrated fail‑safe redundancy
• Digital signal processing per channel
• IP‑networked on OMNEO for audio and control

This is a flexible and compact multi‑channel power amplifier for 100 V or 70 V loudspeaker systems in Public Address and Voice Alarm applications. It fits in centralized system topologies, but also supports decentralized system topologies because of its OMNEO IP‑network connection, combined with DC‑power from a multifunction power supply.
The output power of each amplifier channel adapts to the connected loudspeaker load, only limited by the total power budget of the whole amplifier. This flexibility, and the integration of a spare amplifier channel, makes it possible to utilize the available power effectively and use less amplifiers for the same loudspeaker load, compared to using traditional amplifiers.
Digital sound processing and control, adjusted to the acoustics and requirements of each zone, allow for better sound quality and speech intelligibility.

Functions
Efficient 4‑channel power amplifier

• Transformerless, galvanically isolated, 70/100 V outputs, with a total loudspeaker output power of 600 W.
• Flexible partitioning of the available output power across all amplifier channels to use it effectively, significantly reducing the amount of required amplifier power in a system.
• Cost and space saving, integrated, independent spare channel for fail‑safe redundancy.
• Class D amplifier channels with two-level power lines for high‑efficiency in all operating conditions; dissipation and heat loss is minimized to save on energy and battery capacity for backup power.

Flexibility in loudspeaker topologies

• A/B outputs on every amplifier channel to support redundant loudspeaker wiring topologies. Both outputs are individually supervised and disabled in case of a fault.
• Class A loop wiring possible between the A and B loudspeaker outputs. Dedicated connection facility
  for an end‑of‑line device to supervise the complete loop, including the B‑output connection.
• Load independent frequency response; the amplifier channels can be used with any loudspeaker load up to the maximum, without any change in audio quality.

Sound quality

• Audio‑over‑IP, using OMNEO, the Bosch high‑quality digital audio interface, compatible with Dante and
  AES67; audio sample rate is 48 kHz with 24‑bit sample size.
• Large signal to noise ratio, wide audio bandwidth and very low distortion and crosstalk.
• Digital signal processing on all amplifier channels, including equalization, limiting and delay, to optimize and tailor the sound in each loudspeaker zone.

Supervision

• Supervision of amplifier operation and all of its connections; faults are reported to the system controller and logged.
• Loudspeaker line integrity supervision without interruption of audio, using end‑of‑line devices (separately available) for best reliability.
• Network link supervision.

Fault tolerance

• Dual OMNEO network connections, supporting Rapid Spanning Tree Protocol (RSTP), for loop through connections to adjacent devices.
• Dual 48 VDC inputs with polarity reversal protection, each with a full power DC/DC converter, operating in tandem for redundancy.
• Fully independent amplifier channels; the integrated spare channel automatically replaces a failing channel, with due regard of the actual sound processing settings.
• All amplifier channels support two independent loudspeaker groups, A and B, enabling redundant loudspeaker wiring topologies.
• Backup analog audio lifeline input driving the spare amplifier channel to serve all connected loudspeaker zones in case both network connections, or the amplifier network interface, would fail.