Well I know that subject line may look funny, but it's true. I was plugging my serial cable into the empeg tonight to load hijack 289 and was using my fingers to guide it in place. As soon as I touched the empeg's case I felt that familiar old tickle running through my fingers.

The current was flowing from the empeg case to my PC's case (via the shield on the serial cable). I snapped my voltmeter up and measured 94 volts AC between the two!! Naturally I thought this to be strange and immediately suspected the empeg power supply. Indeed, I unplugged the power supply and measured the voltage between each contact and my PC case and they both gave 94 volts AC.

I haven't confirmed that the live AC source is originating from the power supply yet, but I'm fairly certain considering I don't get the same behaviour between my PC and another PC which are both earthed.

This could explain the soft humming noise I've always had when I've got my empeg hooked up to my hifi amp and powered by the stock IEC supply. In fact, I never use the stock supply for hifi purposes anymore because of that.

Is this potentially A Bad Thing?


Thanks,
Aragon

It certainly could be a faulty power supply or some kind of a ground loop problem.

You could try a different power supply and see if the problem goes away.

This is strange for the IEC supply, as it has an earth terminal. Are you sure the outlet it's plugged into has a good earth?

The 2-prong (unearthed) adaptors will cause the empeg to float at roughly half mains voltage - but with very low current flow (almost anything will earth it, but if you touch both a grounded object and the empeg you'll feel a tingle).

Actually, my Vaio (also being metal) suffers from this exact problem as it only has a 2-pin PSU. I used to get tingles from my (earthed) empeg when holding a (floating at ~100v) serial cable connected to the laptop...

Hugo

That IEC supply caused a nasty ground loop when I plugged the player into a friend's home stereo, but the 2-prong adapter did not...

Yes I have the same problem, when I touch the usb plug and the empeg at the same time I get shocked. I also have the little power supply, but Im shure that the problem is that the outlet the both are plugged into, its not grounded. I live in a historic house built in 1892 so I dont think they knew what grounds were check you outlet with one of those little tester thingies with the three neon lights to see if the outlet is properly wired, the reverseing of the hot and neutral could also cause this. Most power back ups and surge protector power strips tell you right on the front if the outlet is properly wired too.

Check that the PC is *really* earthed. I've been shocked (literally) by how bad some power supplies are now.

Cheers,

Rex.

It could be this cheap power strip I'm using that isn't properly earthed. Will have to experiment on some of the other wall sockets when I have a chance.

Thanks,
Aragon