<snip> I need to do something to degauss the poles, as the zero offset is a bit poor<snip>
My immediate suggestion would be a transformer with a low voltage secondary (old worlde non electronic halogen transformer) with an appropriate load (say 100w at 12v), maybe 20 turns through the meter clamp, ... equivalent of 160 amps... then turn it off via a dimmer?
Yes good point, I did consider that but figured the spikey nature of the waveform still diminishes toward zero... the idea of a tape head degausser is simpler. If my idea were taken forward, a variac would be better, or even a bl**dy great rheostat if one is available?
