Hi all,

I Have been using the audio trigger in an audio power Amplifier. The Amplifier turns on via the Audio trigger's circuit through the volume control of the audio channels through a preamplifier and turns off if it does not get the required volume input. The Audio Trigger Circuit PCB in the amplifier has a potentiometer and some Resistors in the signal path. The Audio trigger sensitivity can be adjusted incrementally via the potentiometer's rotational range, which is limited to about 200-220 degrees, to high at 50 mV max by turning the potentiometer max anticlockwise(8 o'clock) and low at 250 mV min by turning the potentiometer max clockwise (4 0'clock) or at 12 o'clock dented position to achieve 100 mV. The high sensitivity of 50 mV seems appropriate on paper for the situation but in practice at volume levels that are comfortable for me the amplifier turns off after about 4-5 minutes because the Audio trigger circuit is not receiving enough mV even at it's highest sensitivity setting of 50 mV (max anticlockwise; 8 o'clock position).

I want to increase the sensitivity to about 20 mV at max setting of the potentiometer( max anticlockwise; 8 o'clock) to avoid frequent turn off during operation of the amplifier. Will I have to change the Potentiometer? Will I have to change one of the resistors in the Trigger's circuit/signal path and if so which one and by how much?

Thank you.

 

To do this you need a schematic to know what to change and what to change it to.
You must either find the schematic online (for free or to buy) or sketch out the schematic by examining the existing circuit board.

 

Nothing available online or otherwise. If I could get the values of the resistors and the pins of the potentiometer they are connected to would that help? The Audio trigger circuit is connected to the audio RCA/XLR input board in the amplifier and uses that voltage to trigger the amplifier.

 

It might enable a fair guess but it wouldn't be more than that.