Bose 901 Series V Equalizer Manual

The Bose 901 Series V Active Equalizer is a critical component designed specifically for use with the Bose 901 Series V Direct/Reflecting® speaker system. It provides precise electronic equalization to achieve the intended acoustic performance, compensating for the speakers' unique design to deliver flat amplitude response in a typical listening room. This manual covers setup, operation, connection guidelines, specifications, and troubleshooting for the equalizer.

Features at a Glance

Key components: Active electronic equalizer unit, power cord, connection cables. The equalizer is essential for proper operation of the Bose 901 Series V speakers.

Installation & Connection

Unpack the equalizer and inspect for damage. Place near your amplifier/receiver on a stable, level surface.

1. Position: Ensure adequate ventilation; do not place inside an enclosed cabinet.
2. Connect to Amplifier: Use provided RCA cables to connect equalizer between your preamp/main amp or tape monitor loop.
3. Connect Speakers: Ensure 901 Series V speakers are properly connected to your amplifier's speaker outputs.
4. Power Connection: Plug the equalizer's power cord into a standard 120V AC outlet.

WARNING! Always turn off your amplifier/receiver before making any connections to prevent damage or shock.

First-Time Setup

Follow these steps to integrate the equalizer into your audio system.

1. System Power Off: Ensure all components (receiver, amp) are powered OFF.
2. Connect in Tape Monitor Loop: Connect equalizer INPUT to TAPE OUT on receiver; OUTPUT to TAPE IN on receiver.
3. Activate Tape Monitor: Engage the TAPE MONITOR switch on your receiver to route signal through the equalizer.
4. Power On: Turn on equalizer first, then your amplifier/receiver.
5. Verify Operation: The power indicator LED should illuminate. Play audio to confirm signal path.

CAUTION! Do not connect the equalizer to a receiver's "PHONO" input. This will cause distortion and potential damage.

Specifications

• Type: Active electronic equalizer.
• Compatibility: Designed exclusively for Bose 901 Series V speakers.
• Frequency Response: Tailored to complement 901 Series V acoustic characteristics.
• Input Impedance: 10 kΩ.
• Output Impedance: 1 kΩ.
• Total Harmonic Distortion: Less than 0.1%.
• Signal-to-Noise Ratio: Better than 90 dB.
• Power Requirements: 120V AC, 60Hz, 5 Watts.
• Dimensions (approx.): 2.5"H x 8.5"W x 6"D.
• Weight: 3 lbs.

Controls and Indicators

Front Panel: POWER switch, LEVEL control, BYPASS switch, Power Indicator LED.

Rear Panel: AC Power inlet, INPUT (from source/preamp), OUTPUT (to amplifier), Ground terminal.

POWER Switch: Turns the equalizer's electronics ON/OFF. The equalizer must be ON for the speakers to sound correct.

LEVEL Control: Adjusts the output level of the equalizer to balance the 901 speakers with other speakers in the system or to match room acoustics.

BYPASS Switch: Engages or disengages the equalization circuit. Use to compare the equalized (correct) sound with the unequalized sound.

Power Indicator: Illuminates when the unit is powered ON.

Connecting to Your System

Primary connection method is via the tape monitor loop of your receiver or preamplifier.

1. Identify the TAPE OUT (Play) and TAPE IN (Record) jacks on your receiver.
2. Connect a pair of RCA cables from TAPE OUT to the INPUT of the Bose equalizer.
3. Connect a second pair from the OUTPUT of the equalizer to TAPE IN on the receiver.
4. Activate the TAPE MONITOR function on your receiver. The signal will now route through the equalizer for all sources.

Tip: If your receiver lacks a tape monitor loop, connect the equalizer between the preamp output and main amplifier input jacks if available.

Equalization & Sound Adjustment

The equalizer's fixed curve is precisely tailored for the 901 Series V. User adjustment is primarily via the LEVEL control.

1. For Normal Listening: Ensure BYPASS switch is OUT (equalization ON).
2. Balancing Level: Play familiar music. Adjust the LEVEL control so the 901 speakers blend seamlessly with the overall soundstage or match the volume of other speakers in a multi-speaker setup.
3. A/B Comparison: Press the BYPASS switch IN to hear the speakers without equalization. Note the significant loss of bass and treble. Return switch to OUT for proper sound.
4. Fine-Tuning: Small adjustments to the LEVEL control may be needed for different types of music or source material.

WARNING! The BYPASS function is for comparison only. The 901 speakers are not designed to be used without their dedicated equalizer for extended listening.

System Calibration

For optimal performance, calibrate the equalizer level in your specific room.

1. Play pink noise or familiar music with consistent tonal balance.
2. Set receiver volume to a moderate, comfortable listening level.
3. Adjust the equalizer's LEVEL control until the sound from the 901 speakers is balanced and natural, without being overly dominant or recessed.
4. Walk around the listening area to ensure even coverage.

Note: The equalization curve is fixed and cannot be adjusted. The LEVEL control only affects overall gain in the equalized path.

Care & Maintenance

Unplug from AC power before cleaning. Use a soft, dry cloth to wipe the exterior. Do not use liquid or aerosol cleaners.

CAUTION! Do not open the cabinet. There are no user-serviceable parts inside. Refer servicing to qualified Bose personnel.

Regulatory Information

FCC Part 15: Class B digital device. Complies with limits for residential use. This device may not cause harmful interference and must accept any interference received. Copyright © Bose Corporation. Bose and the Bose medallion are trademarks of Bose Corporation. For support in the USA and Canada, contact Bose Customer Service or visit www.bose.com.

Troubleshooting

Service: Do not attempt internal repair. Contact Bose Customer Service for support: 1-800-999-2673 or www.bose.com.