The Snake Oil Machine

[Patrick Dixon]

I'm with Barry - should we have a poll ;-)

[Joe]

We must avoid 'absolutism' here. (As a mere mug punter, with the science/engineering knowledge of a particularly dim goldfish, I've no idea whether such devices are safe or unsafe when used with Class II appliances, whatever they may be).

[Macca]

We must avoid 'absolutism' here. (As a mere mug punter, with the science/engineering knowledge of a particularly dim goldfish, I've no idea whether such devices are safe or unsafe when used with Class II appliances, whatever they may be).

It's all been explained already. Stop dozing off at the back of the class and pay attention!

[Joe]

It's all been explained already. Stop dozing off at the back of the class and pay attention!

Ha! I remember in Economics A level classes, possibly the single most boring experience of my life, the teacher, Ted Rudd, used to think he could catch me out by barking a random question at me when he thought I'd dozed off. To his annoyance, I always knew what he'd been saying, even if, to all appearances, I was fast asleep. (Cunningly, I wore tinted glasses, so nobody could tell whether my eyes were open or closed).

Scott Adams, who does the 'Dilbert' cartoons, once described the only two things he could remember about economics, having done a Master's degree in the subject:

a) Something about supply and demand, and
b) It's not actually possible to die of boredom, though you might wish it was.

[mikmas]

We must avoid 'absolutism' here. (As a mere mug punter, with the science/engineering knowledge of a particularly dim goldfish, I've no idea whether such devices are safe or unsafe when used with Class II appliances, whatever they may be).

I'm still struggling with the concept that a 'Class II' appliance is not the same thing as a 'Class 2' appliance - let alone what's safe or unsafe when used with either

[Macca]

Scott Adams, who does the 'Dilbert' cartoons, once described the only two things he could remember about economics, having done a Master's degree in the subject:

a) Something about supply and demand, and
b) It's not actually possible to die of boredom, though you might wish it was.

LOL. can't be any worse than Latin; the only I things I learned were that nouns decline, verbs conjugate and that if you are bored enough 40 minutes can drag on so long it can seem like an entire lifetime.

[Barry]

If you connect a Class II appliance to mains earth, then it is no longer a Class II appliance and is required to pass a different set of safety tests to guarantee its CE compliance.

This marvellous lead therefore strikes me as not only a pointless exercise (IMHO of course) but a slightly dodgy one.

That would imply you should never connect a Class II appliance to a Class I appliance, as the latter having its signal ground connected to mains earth will then earth the signal ground of the Class II device.

[walpurgis]

Hmm. It gets more complicated as it goes along.

[Beobloke]

^^ what he said! ^^

[Barry]

Class I appliances have their chassis connected to earth, but that doesn't necessarily mean their audio signal 0V is connected to earth.

True, it doesn't necessarily mean the audio signal 0V is connected to ground, but neither does it necessarily imply it is floating with respect to the mains earth. It might be connected to mains earth via a resistor having a low value, say 10 Ohm, as is effected by a "ground lift" option.