Theory Of Operation - Bose 1600VI Service Manual

1. General
The Bose Model 1600VI and 1800VI Professional Stereo Power Amplifiers are two-channel,
®
installed/portable amplifiers made for professional sound applications. The 1600VI is rated at
240 Watts into 8 Ohms and 325 Watts into 4 Ohms. In the bridged-mono setting it can deliver
700 Watts. The 1800VI is rated at 450 Watts into 8 Ohms and 600 Watts into 4 Ohms. In the
bridged-mono setting it can deliver 1400 Watts.
The protection circuits designed into the amplifiers will protect them from unexpected faults,
excessive temperature, continuous current limiting and shorted outputs.
The balanced inputs use high quality, high common-mode rejection differential amplifiers for
exceptional hum and noise rejection.
Through the use of equalization cards the amplifier can provide active equalization for Bose
402™, 502 A, 502B, 802
®
loudspeakers. These cards fit into the J6, Channel 1 and J7, Channel 2 connectors located on
the Input Module motherboard or the Bose ACM-1 Amplifier Control Module.
Additional Features are as follows:
• Two input connectors per channel allow 1/4" TRS, XLR, or quick connect terminal block
connection
• Two input connectors for each channel are wired in parallel
• Accepts balanced or unbalanced lines
• Independent CH 1 and CH 2 Level Controls with 11 detented positions
• Level Control Defeat Switch
• Dual Mono Mode for combining the power of both channels into a single higher powered
channel
• Sequencer connection for sequentially powering-up multiple amplifiers to limit instantaneous
in-rush current
• Bi-Amp/Full Range configurable
• Internally configurable for Parallel Mono mode for single channel low impedance operation
• Internally configurable for 0.775V or 1.5V rms input sensitivity
• Internally configurable input polarity of XLR connectors
• Class H dual-rail power supply
• Additional protection circuitry includes Clipping Eliminator, AC Lines Fuse
• Power Connected/Standby Indicator
• 7 LED display per channel, including power ready and Clip/Protect indicators
• Two-speed fan cooled
2. Circuit Descriptions
This section discusses the theory of operation of the 1600VI and 1800VI Amplifiers.
For a better understanding of the circuitry involved, refer to the schematics included with this
manual. Component pin designation is notated as follows: U1-7 means U1 at pin 7.
Unless otherwise noted, this discussion centers around the CH 1 circuitry.
The CH 2 circuitry is essentially identical.

THEORY OF OPERATION

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