Bose SA2 Service Manual

The Bose SA2 is a professional power amplifier designed for commercial and installed sound applications. It features advanced protection circuitry, efficient Class-D amplification, configurable input/output options, and network control capabilities via Bose ControlSpace® software. Below are key sections for safety, features, installation, configuration, operation, and troubleshooting.

Features at a Glance

Key components: Class-D amplifier module, Network control port, Input/Output connectors, Status indicators, Protection circuitry.

Feature	Description
Amplifier Type	High-efficiency Class-D
Power Output	Configurable per channel (see specifications)
Network Control	Ethernet port for Bose ControlSpace® remote monitoring and control
Input Connectors	Combined XLR/TRS jack, Euroblock terminal
Output Connectors	Speakon® NL4, binding posts
Protection Circuits	Thermal, short-circuit, DC offset, overload, ultrasonic
Status Indicators	Power, Signal, Limit, Fault, Network
Cooling	Variable-speed fan
Power Connector	IEC mains inlet with integrated fuse holder
Mounting	Rack-mountable (2U height)

Installation

Unpack and inspect contents. Ensure proper rack space and ventilation.

1. Rack Mounting: Secure amplifier using provided screws in a standard 19-inch rack. Allow minimum 1U space above for airflow.
2. Power Connection: Connect to appropriate AC mains voltage as indicated on rear label.
3. Signal Input: Connect source using XLR, TRS, or Euroblock connectors.
4. Speaker Output: Connect speakers to Speakon® or binding post outputs, observing correct polarity.
5. Network Connection (Optional): Connect Ethernet cable for remote control.

WARNING! Disconnect power before making connections. Ensure proper grounding. Unit is heavy; use two-person lift for rack mounting.

First-Time Setup

Apply power and verify operation.

1. Power On: Switch rear panel POWER switch to ON. Green POWER LED should illuminate.
2. Signal Verification: Apply a low-level audio signal. Green SIGNAL LED(s) should indicate presence.
3. Output Configuration: Set output mode (Stereo, Parallel, Bridge Mono) via rear panel switches if applicable.
4. Input Sensitivity: Adjust input sensitivity switch (0.775V, 1.0V, 1.4V) to match source.
5. Network Setup (Optional): Assign IP address via DHCP or static method using front panel or software.

CAUTION! Verify speaker impedance matches amplifier's minimum rating before applying full power.

Specifications

• Amplifier Topology: Class-D with advanced power supply.
• Power Output (per channel): Varies by model and impedance (refer to datasheet).
• Frequency Response: 20 Hz - 20 kHz, +0/-1 dB.
• Total Harmonic Distortion (THD): <0.05% at rated power.
• Signal-to-Noise Ratio: >100 dB, A-weighted.
• Input Impedance: 20 kΩ balanced, 10 kΩ unbalanced.
• Input Sensitivity: Selectable (0.775V, 1.0V, 1.4V for full output).
• Cooling: Variable-speed fan, front-to-rear airflow.
• Power Requirements: 100-240V AC, 50/60 Hz, auto-sensing.
• Operating Temperature: 0°C to 40°C (32°F to 104°F).
• Dimensions (W x H x D): Standard 19" rack width, 2U height, depth per model.
• Weight: Varies by model (approximately 7-9 kg / 15-20 lbs).

Controls and Settings

Front Panel: POWER switch, Status LEDs (Power, Signal, Limit, Fault, Network). Rear Panel: Input/Output connectors, Configuration switches, Fuse holder.

Configuration Switches: Input Sensitivity (0.775V/1.0V/1.4V), Output Mode (Stereo/Parallel/Bridge), Network Address (if no DHCP).

LED Indicators: POWER (Green - On), SIGNAL (Green - Audio present), LIMIT (Amber - Clipping/limiting active), FAULT (Red - Protection engaged), NETWORK (Green/Amber - Link/Activity).

Connecting Devices

Inputs: Balanced XLR/TRS combo jack or Euroblock. Outputs: Speakon® NL4 (pins 1+/1- and 2+/2-), Binding posts.

1. Turn off amplifier and source before connecting.
2. Use shielded, balanced cables for inputs to minimize noise.
3. For bridge mono operation, connect speaker between Channel 1+ and Channel 2+ on Speakon, observing maximum impedance.
4. Ensure speaker cables are of adequate gauge for length and power.

Tip: Label all cables for easy identification in multi-amplifier installations.

Network Configuration

Remote monitoring and control via Bose ControlSpace® software.

1. Physical Connection: Connect Ethernet cable from amplifier to network switch/router.
2. IP Address Assignment: By default, amplifier attempts DHCP. If no DHCP server, it uses a link-local address (169.254.x.x).
3. Software Discovery: Open ControlSpace® Designer or Device Manager. The amplifier should appear in the device list.
4. Configuration: Assign static IP, subnet mask, gateway if required by network policy.
5. Control Features: Remote power on/off, mute, gain adjustment, monitoring of status, temperature, and fault conditions.

WARNING! Configure network settings in accordance with local IT policies. Isolate audio network if possible for reliability.

Protection Features

Comprehensive protection circuits safeguard amplifier and speakers.

• Thermal: Reduces output or shuts down if internal temperature exceeds safe limit.
• Short-Circuit/DC Offset: Disables output if speaker short or significant DC is detected.
• Overload/Current Limit: Protects against sustained excessive current demand.
• Ultrasonic/Infrasonic: Filters out potentially damaging frequencies beyond audio band.
• Power Supply: Over-voltage and under-voltage protection.

Fault condition is indicated by red FAULT LED. Amplifier typically auto-resets when condition clears and unit cools.

Care & Maintenance

Disconnect from mains before any maintenance.

1. Cleaning: Use dry, soft cloth to wipe exterior. Do not use liquid or aerosol cleaners.
2. Ventilation: Keep vents clear of dust and obstructions. Periodically vacuum intake grille if in dusty environment.
3. Fuse Replacement: If fuse blows, identify and correct cause before replacing with same type and rating.
4. Firmware Updates: Check Bose Professional website for firmware updates via network connection.

CAUTION! No user-serviceable parts inside. Refer servicing to qualified Bose service personnel.

Regulatory Information

Complies with relevant safety and EMC standards including UL, CE, FCC. This product conforms to the European Union's RoHS directive. The CE mark indicates conformity with applicable EU directives. For FCC: This device complies with Part 15 of the FCC Rules. Operation is subject to the condition that this device does not cause harmful interference.

Copyright and trademarks are property of Bose Corporation. For technical support, visit pro.bose.com or contact your local Bose Professional distributor.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power (POWER LED off)	Mains power, fuse, switch	Check AC outlet, power cord, rear panel switch. Verify fuse.
No output (POWER LED on)	Input signal, muting, protection	Verify source is active and connected. Check for FAULT LED. Ensure amplifier not muted remotely.
Intermittent sound or distortion	Cables, connectors, clipping	Check all connections for tightness and corrosion. Reduce input gain if LIMIT LED activates.
Amplifier shuts down during use	Overheating, low impedance	Ensure adequate ventilation. Verify speaker impedance is not below minimum rating.
FAULT LED illuminated	Short circuit, thermal, DC fault	Disconnect speaker loads and power cycle. If LED remains, internal fault - contact service.
No network connection	Cable, IP address, switch	Check Ethernet cable and link LEDs. Verify IP address assignment (DHCP/static).

Reset: Power cycle to clear temporary faults. For persistent issues, note fault LED blink pattern for service reference.

Service: Do not open chassis. Contact Bose Professional Support or authorized service center. Have model and serial number ready.