Spectral DMA180 Series1 versus DMA180 Series 2

I've been using the 180 with a DMC20 and reference MIT cables since buying in mid 90's.
Have found "significant" AC power conditioning enabled -astonishing - performance improvement for the 180.
Does someone have direct experience comparing the Series 1 vs 2?
Could you describe the differences?
Do you know what technical differences were involved?
Have you used AC conditioning with these amps? If so, what types and what results?