
Qualified Service Personnel Only
Woofer Crossover
The input signal at U4A pin 1 connects to the 3200Hz 2nd order
Thermal Protection
The thermal protection is activated, and shuts down audio operation, when the amplifier heatsink reaches an exces- sively high temperature. The voltage divider R22 and R23 establishes the reference voltage on pin 5 of U5B. The control voltage on pin 4 is established by the voltage divider TS1 and R25. TS1 is a NTC (Negative Temperature Coefficient) thermistor mounted on the heatsink. As TS1 warms and the resistance falls, the voltage on pin 4 rises. When the voltage on pin 4 exceeds the voltage on pin 5, the output on pin 2 goes low, shutting down the Soft Start switches Q8 and Q24, and lighting the CLIP/THERMAL indicator red.
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