I occasionally use an Ampeg SVT-210HE on top of my SVT-410HLF to get speakers up closer to my ear and I have noticed that the horn sometimes goes quiet. Having checked a number of things I still have not found any obvious explanation to the problem... It does not take very high SPL for the cut out to happen, even if it has not yet happened at "living room level". Over 90-ish dB and all bets are off, though. When the horn is functional it sounds just as it is supposed to - no noises or distortion. I did take the horn and driver unit apart and the voice coil and its protective laquer looks fine to the naked eye. (So there should be no shorting aganst the magnet assembly.) The connectors on the crossover are OK and so are the wires. I also opened the Lpad and found no visible damage. No corrosion on the light bulb and holder. The lamp was labelled as 28V + a number that I do not remember. It could be worth mentioning that I run the horn padded down about 8-10 dB. (Basically only 25-30% up on the Lpad's range.) I do not know if the problem persists at higher horn settings. Any suggestions?