Hi Gerry, Thank you for your answer. If I understand measurement categories correctly, the measurements should fall into CAT I since I'm not going to measure anything connected to mains, i.e. I'm not going to measure primary side of the transformer. Even though it is not a "low voltage" source, the ...

Hi, I'm about to build a guitar valve preamp where supply voltage can be as high as 300Vdc, signals usually in tens of V with offset of ~150V. The supply is of course isolated by a transformer from mains. I wonder whether I can use standard 1:100 probe with PicoScope from 2000 Series or whether I ne...