Ecler PAM1400, Service Manual

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13
CLIP CIRCUIT
The other half of IC307(4001) is used in the clip circuit. Given that we have two gates more and we just need
one for our purposes we will connect them in parallel for a higher output current and a more effective LED lighting up.
The clip threshold or point where we want the LED to light up is determined by the zener D313. In our case it is
between 0.5 and 1dB or, what is the same, when the output signal level over the load reaches a value close to that of
the power supply (+V), exactly Vout = V - 5.6, moment in which Q304 loses the base-emitter voltage stopping
conduction; this makes the zener D312 voltage disappear (0V) and the output from IC307 go to "1" logic (+10V),
making the LED light up.