oh, the lesson was learnt. i was with a tech at the time, he checked it over and luckily it was just some adhesive that had smoked when it got hot. it was a good warning before it actually failed! we were trying out the amp with a Divo OV4 in it, self biasing unit, so we were winding it up to see how it fared. i wouldn't normally have it cranked as high as that. there is no master volume on this baby, hence the attenuator, which is rated at 100 watts, while the amp at full tilt is putting out more like 130. it was careless of us, and we're lucky we just got a bit of smoke to scare us. we won't make that mistake again!