I've had problems with every hopper that uses a sound sensor period. Turn them up high enough to work, you get insane stack tension and break paint. Turn them down you get no paint. I gave up on all of them.
I think the problem is that some sensors are just more sensitive than others. I also heard back in the day that the hopper boards will detect the normal noise level in the area and look for something higher than that to set it off. So if you turn it on in a noisy place, the hopper will be less sensitive. I don't know if that's true or not so take it for what it's worth lol.
Axe PDD LE F/S
PM for pics.