Speaker Protection Board

are you using separately rectified and smoothed secondaries? if so, please check this out - if not wired correctly, the board will not work. Note where the sense connection goes.

1737648365385.png
 
  • I have a +/- power supply using 4 diodes only (I guess this is called split rail according to post 194?). In any case, I connected "AC sense" of the PCB to either VAC1 or VAC4. No sound from the speaker in both cases.

  • V+ and 0V (as labelled on the speaker protection PCB) is connected to V+ and ground of power supply respectively.

  • I believed I have connected/oriented the UPC and VOM chips correctly. I will check again.

  • I can hear music if I connect the power amp output directly to the speakers.

  • For this test, I only connected 1 channel (I believe it was the left one). This should be ok. right?

  • is it possible the DC output of the power amp is so great, it's triggering the protection?